了解 Auto Scaling 的基礎知識 AWS SDK

global using Amazon.AutoScaling;
global using Amazon.AutoScaling.Model;
global using Amazon.CloudWatch;
global using AutoScalingActions;
global using Microsoft.Extensions.DependencyInjection;
global using Microsoft.Extensions.Hosting;
global using Microsoft.Extensions.Logging;
global using Microsoft.Extensions.Logging.Console;
global using Microsoft.Extensions.Logging.Debug;



using Amazon.EC2;
using Microsoft.Extensions.Configuration;
using Host = Microsoft.Extensions.Hosting.Host;

namespace AutoScalingBasics;

public class AutoScalingBasics
{

    static async Task Main(string[] args)
    {
        // Set up dependency injection for Amazon EC2 Auto Scaling, Amazon
        // CloudWatch, and Amazon EC2.
        using var host = Host.CreateDefaultBuilder(args)
            .ConfigureLogging(logging =>
                logging.AddFilter("System", LogLevel.Debug)
                    .AddFilter<DebugLoggerProvider>("Microsoft", LogLevel.Information)
                    .AddFilter<ConsoleLoggerProvider>("Microsoft", LogLevel.Trace))
            .ConfigureServices((_, services) =>
            services.AddAWSService<IAmazonAutoScaling>()
                .AddAWSService<IAmazonCloudWatch>()
                .AddAWSService<IAmazonEC2>()
                .AddTransient<AutoScalingWrapper>()
                .AddTransient<CloudWatchWrapper>()
                .AddTransient<EC2Wrapper>()
                .AddTransient<UIWrapper>()
            )
            .Build();


        var autoScalingWrapper = host.Services.GetRequiredService<AutoScalingWrapper>();
        var cloudWatchWrapper = host.Services.GetRequiredService<CloudWatchWrapper>();
        var ec2Wrapper = host.Services.GetRequiredService<EC2Wrapper>();
        var uiWrapper = host.Services.GetRequiredService<UIWrapper>();

        var configuration = new ConfigurationBuilder()
            .SetBasePath(Directory.GetCurrentDirectory())
            .AddJsonFile("settings.json") // Load test settings from .json file.
            .AddJsonFile("settings.local.json",
                true) // Optionally load local settings.
            .Build();

        var imageId = configuration["ImageId"];
        var instanceType = configuration["InstanceType"];
        var launchTemplateName = configuration["LaunchTemplateName"];

        launchTemplateName += Guid.NewGuid().ToString();

        // The name of the Auto Scaling group.
        var groupName = configuration["GroupName"];

        uiWrapper.DisplayTitle("Auto Scaling Basics");
        uiWrapper.DisplayAutoScalingBasicsDescription();

        // Create the launch template and save the template Id to use when deleting the
        // launch template at the end of the application.
        var launchTemplateId = await ec2Wrapper.CreateLaunchTemplateAsync(imageId!, instanceType!, launchTemplateName);

        // Confirm that the template was created by asking for a description of it.
        await ec2Wrapper.DescribeLaunchTemplateAsync(launchTemplateName);

        uiWrapper.PressEnter();

        var availabilityZones = await ec2Wrapper.ListAvailabilityZonesAsync();

        Console.WriteLine($"Creating an Auto Scaling group named {groupName}.");
        await autoScalingWrapper.CreateAutoScalingGroupAsync(
            groupName!,
            launchTemplateName,
            availabilityZones.First().ZoneName);

        // Keep checking the details of the new group until its lifecycle state
        // is "InService".
        Console.WriteLine($"Waiting for the Auto Scaling group to be active.");

        List<AutoScalingInstanceDetails> instanceDetails;

        do
        {
            instanceDetails = await autoScalingWrapper.DescribeAutoScalingInstancesAsync(groupName!);
        }
        while (instanceDetails.Count <= 0);

        Console.WriteLine($"Auto scaling group {groupName} successfully created.");
        Console.WriteLine($"{instanceDetails.Count} instances were created for the group.");

        // Display the details of the Auto Scaling group.
        instanceDetails.ForEach(detail =>
        {
            Console.WriteLine($"Group name: {detail.AutoScalingGroupName}");
        });

        uiWrapper.PressEnter();

        uiWrapper.DisplayTitle("Metrics collection");
        Console.WriteLine($"Enable metrics collection for {groupName}");
        await autoScalingWrapper.EnableMetricsCollectionAsync(groupName!);

        // Show the metrics that are collected for the group.

        // Update the maximum size of the group to three instances.
        Console.WriteLine("--- Update the Auto Scaling group to increase max size to 3 ---");
        int maxSize = 3;
        await autoScalingWrapper.UpdateAutoScalingGroupAsync(groupName!, launchTemplateName, maxSize);

        Console.WriteLine("--- Describe all Auto Scaling groups to show the current state of the group ---");
        var groups = await autoScalingWrapper.DescribeAutoScalingGroupsAsync(groupName!);

        uiWrapper.DisplayGroupDetails(groups!);

        uiWrapper.PressEnter();

        uiWrapper.DisplayTitle("Describe account limits");
        await autoScalingWrapper.DescribeAccountLimitsAsync();

        uiWrapper.WaitABit(60, "Waiting for the resources to be ready.");

        uiWrapper.DisplayTitle("Set desired capacity");
        int desiredCapacity = 2;
        await autoScalingWrapper.SetDesiredCapacityAsync(groupName!, desiredCapacity);

        Console.WriteLine("Get the two instance Id values");

        // Empty the group before getting the details again.
        groups!.Clear();
        groups = await autoScalingWrapper.DescribeAutoScalingGroupsAsync(groupName!);
        if (groups is not null)
        {
            foreach (AutoScalingGroup group in groups)
            {
                Console.WriteLine($"The group name is {group.AutoScalingGroupName}");
                Console.WriteLine($"The group ARN is {group.AutoScalingGroupARN}");
                var instances = group.Instances;
                foreach (Amazon.AutoScaling.Model.Instance instance in instances)
                {
                    Console.WriteLine($"The instance id is {instance.InstanceId}");
                    Console.WriteLine($"The lifecycle state is {instance.LifecycleState}");
                }
            }
        }

        uiWrapper.DisplayTitle("Scaling Activities");
        Console.WriteLine("Let's list the scaling activities that have occurred for the group.");
        var activities = await autoScalingWrapper.DescribeScalingActivitiesAsync(groupName!);
        if (activities is not null)
        {
            activities.ForEach(activity =>
            {
                Console.WriteLine($"The activity Id is {activity.ActivityId}");
                Console.WriteLine($"The activity details are {activity.Details}");
            });
        }

        // Display the Amazon CloudWatch metrics that have been collected.
        var metrics = await cloudWatchWrapper.GetCloudWatchMetricsAsync(groupName!);
        Console.WriteLine($"Metrics collected for {groupName}:");
        metrics.ForEach(metric =>
        {
            Console.Write($"Metric name: {metric.MetricName}\t");
            Console.WriteLine($"Namespace: {metric.Namespace}");
        });

        var dataPoints = await cloudWatchWrapper.GetMetricStatisticsAsync(groupName!);
        Console.WriteLine("Details for the metrics collected:");
        dataPoints.ForEach(detail =>
        {
            Console.WriteLine(detail);
        });

        // Disable metrics collection.
        Console.WriteLine("Disabling the collection of metrics for {groupName}.");
        var success = await autoScalingWrapper.DisableMetricsCollectionAsync(groupName!);

        if (success)
        {
            Console.WriteLine($"Successfully stopped metrics collection for {groupName}.");
        }
        else
        {
            Console.WriteLine($"Could not stop metrics collection for {groupName}.");
        }

        // Terminate all instances in the group.
        uiWrapper.DisplayTitle("Terminating Auto Scaling instances");
        Console.WriteLine("Now terminating all instances in the Auto Scaling group.");

        if (groups is not null)
        {
            groups.ForEach(group =>
            {
                // Only delete instances in the AutoScaling group we created.
                if (group.AutoScalingGroupName == groupName)
                {
                    group.Instances.ForEach(async instance =>
                    {
                        await autoScalingWrapper.TerminateInstanceInAutoScalingGroupAsync(instance.InstanceId);
                    });
                }
            });
        }

        // After all instances are terminated, delete the group.
        uiWrapper.DisplayTitle("Clean up resources");
        Console.WriteLine("Deleting the Auto Scaling group.");
        await autoScalingWrapper.DeleteAutoScalingGroupAsync(groupName!);

        // Delete the launch template.
        var deletedLaunchTemplateName = await ec2Wrapper.DeleteLaunchTemplateAsync(launchTemplateId);

        if (deletedLaunchTemplateName == launchTemplateName)
        {
            Console.WriteLine("Successfully deleted the launch template.");
        }

        Console.WriteLine("The demo is now concluded.");
    }
}


namespace AutoScalingBasics;

/// <summary>
/// A class to provide user interface methods for the EC2 AutoScaling Basics
/// scenario.
/// </summary>
public class UIWrapper
{
    public readonly string SepBar = new('-', Console.WindowWidth);

    /// <summary>
    /// Describe the steps in the EC2 AutoScaling Basics scenario.
    /// </summary>
    public void DisplayAutoScalingBasicsDescription()
    {
        Console.WriteLine("This code example performs the following operations:");
        Console.WriteLine(" 1. Creates an Amazon EC2 launch template.");
        Console.WriteLine(" 2. Creates an Auto Scaling group.");
        Console.WriteLine(" 3. Shows the details of the new Auto Scaling group");
        Console.WriteLine("    to show that only one instance was created.");
        Console.WriteLine(" 4. Enables metrics collection.");
        Console.WriteLine(" 5. Updates the Auto Scaling group to increase the");
        Console.WriteLine("    capacity to three.");
        Console.WriteLine(" 6. Describes Auto Scaling groups again to show the");
        Console.WriteLine("    current state of the group.");
        Console.WriteLine(" 7. Changes the desired capacity of the Auto Scaling");
        Console.WriteLine("    group to use an additional instance.");
        Console.WriteLine(" 8. Shows that there are now instances in the group.");
        Console.WriteLine(" 9. Lists the scaling activities that have occurred for the group.");
        Console.WriteLine("10. Displays the Amazon CloudWatch metrics that have");
        Console.WriteLine("    been collected.");
        Console.WriteLine("11. Disables metrics collection.");
        Console.WriteLine("12. Terminates all instances in the Auto Scaling group.");
        Console.WriteLine("13. Deletes the Auto Scaling group.");
        Console.WriteLine("14. Deletes the Amazon EC2 launch template.");
        PressEnter();
    }

    /// <summary>
    /// Display information about the Amazon Ec2 AutoScaling groups passed
    /// in the list of AutoScalingGroup objects.
    /// </summary>
    /// <param name="groups">A list of AutoScalingGroup objects.</param>
    public void DisplayGroupDetails(List<AutoScalingGroup> groups)
    {
        if (groups is null)
            return;

        groups.ForEach(group =>
        {
            Console.WriteLine($"Group name:\t{group.AutoScalingGroupName}");
            Console.WriteLine($"Group created:\t{group.CreatedTime}");
            Console.WriteLine($"Maximum number of instances:\t{group.MaxSize}");
            Console.WriteLine($"Desired number of instances:\t{group.DesiredCapacity}");
        });
    }

    /// <summary>
    /// Display a message and wait until the user presses enter.
    /// </summary>
    public void PressEnter()
    {
        Console.Write("\nPress <Enter> to continue. ");
        _ = Console.ReadLine();
        Console.WriteLine();
    }

    /// <summary>
    /// Pad a string with spaces to center it on the console display.
    /// </summary>
    /// <param name="strToCenter">The string to be centered.</param>
    /// <returns>The padded string.</returns>
    public string CenterString(string strToCenter)
    {
        var padAmount = (Console.WindowWidth - strToCenter.Length) / 2;
        var leftPad = new string(' ', padAmount);
        return $"{leftPad}{strToCenter}";
    }

    /// <summary>
    /// Display a line of hyphens, the centered text of the title and another
    /// line of hyphens.
    /// </summary>
    /// <param name="strTitle">The string to be displayed.</param>
    public void DisplayTitle(string strTitle)
    {
        Console.WriteLine(SepBar);
        Console.WriteLine(CenterString(strTitle));
        Console.WriteLine(SepBar);
    }

    /// <summary>
    /// Display a countdown and wait for a number of seconds.
    /// </summary>
    /// <param name="numSeconds">The number of seconds to wait.</param>
    public void WaitABit(int numSeconds, string msg)
    {
        Console.WriteLine(msg);

        // Wait for the requested number of seconds.
        for (int i = numSeconds; i > 0; i--)
        {
            System.Threading.Thread.Sleep(1000);
            Console.Write($"{i}...");
        }

        PressEnter();
    }
}

定義案例呼叫的函數，以管理啟動範本和指標。這些功能包含了 Auto ScalingEC2，Amazon 和 CloudWatch 操作。

namespace AutoScalingActions;

using Amazon.AutoScaling;
using Amazon.AutoScaling.Model;

/// <summary>
/// A class that includes methods to perform Amazon EC2 Auto Scaling
/// actions.
/// </summary>
public class AutoScalingWrapper
{
    private readonly IAmazonAutoScaling _amazonAutoScaling;

    /// <summary>
    /// Constructor for the AutoScalingWrapper class.
    /// </summary>
    /// <param name="amazonAutoScaling">The injected Amazon EC2 Auto Scaling client.</param>
    public AutoScalingWrapper(IAmazonAutoScaling amazonAutoScaling)
    {
        _amazonAutoScaling = amazonAutoScaling;
    }


    /// <summary>
    /// Create a new Amazon EC2 Auto Scaling group.
    /// </summary>
    /// <param name="groupName">The name to use for the new Auto Scaling
    /// group.</param>
    /// <param name="launchTemplateName">The name of the Amazon EC2 Auto Scaling
    /// launch template to use to create instances in the group.</param>
    /// <returns>A Boolean value indicating the success of the action.</returns>
    public async Task<bool> CreateAutoScalingGroupAsync(
        string groupName,
        string launchTemplateName,
        string availabilityZone)
    {
        var templateSpecification = new LaunchTemplateSpecification
        {
            LaunchTemplateName = launchTemplateName,
        };

        var zoneList = new List<string>
            {
                availabilityZone,
            };

        var request = new CreateAutoScalingGroupRequest
        {
            AutoScalingGroupName = groupName,
            AvailabilityZones = zoneList,
            LaunchTemplate = templateSpecification,
            MaxSize = 6,
            MinSize = 1
        };

        var response = await _amazonAutoScaling.CreateAutoScalingGroupAsync(request);
        Console.WriteLine($"{groupName} Auto Scaling Group created");
        return response.HttpStatusCode == System.Net.HttpStatusCode.OK;
    }



    /// <summary>
    /// Retrieve information about Amazon EC2 Auto Scaling quotas to the
    /// active AWS account.
    /// </summary>
    /// <returns>A Boolean value indicating the success of the action.</returns>
    public async Task<bool> DescribeAccountLimitsAsync()
    {
        var response = await _amazonAutoScaling.DescribeAccountLimitsAsync();
        Console.WriteLine("The maximum number of Auto Scaling groups is " + response.MaxNumberOfAutoScalingGroups);
        Console.WriteLine("The current number of Auto Scaling groups is " + response.NumberOfAutoScalingGroups);
        return response.HttpStatusCode == System.Net.HttpStatusCode.OK;
    }



    /// <summary>
    /// Retrieve a list of the Amazon EC2 Auto Scaling activities for an
    /// Amazon EC2 Auto Scaling group.
    /// </summary>
    /// <param name="groupName">The name of the Amazon EC2 Auto Scaling group.</param>
    /// <returns>A list of Amazon EC2 Auto Scaling activities.</returns>
    public async Task<List<Amazon.AutoScaling.Model.Activity>> DescribeScalingActivitiesAsync(
        string groupName)
    {
        var scalingActivitiesRequest = new DescribeScalingActivitiesRequest
        {
            AutoScalingGroupName = groupName,
            MaxRecords = 10,
        };

        var response = await _amazonAutoScaling.DescribeScalingActivitiesAsync(scalingActivitiesRequest);
        return response.Activities;
    }



    /// <summary>
    /// Get data about the instances in an Amazon EC2 Auto Scaling group.
    /// </summary>
    /// <param name="groupName">The name of the Amazon EC2 Auto Scaling group.</param>
    /// <returns>A list of Amazon EC2 Auto Scaling details.</returns>
    public async Task<List<AutoScalingInstanceDetails>> DescribeAutoScalingInstancesAsync(
        string groupName)
    {
        var groups = await DescribeAutoScalingGroupsAsync(groupName);
        var instanceIds = new List<string>();
        groups!.ForEach(group =>
        {
            if (group.AutoScalingGroupName == groupName)
            {
                group.Instances.ForEach(instance =>
                {
                    instanceIds.Add(instance.InstanceId);
                });
            }
        });

        var scalingGroupsRequest = new DescribeAutoScalingInstancesRequest
        {
            MaxRecords = 10,
            InstanceIds = instanceIds,
        };

        var response = await _amazonAutoScaling.DescribeAutoScalingInstancesAsync(scalingGroupsRequest);
        var instanceDetails = response.AutoScalingInstances;

        return instanceDetails;
    }



    /// <summary>
    /// Retrieve a list of information about Amazon EC2 Auto Scaling groups.
    /// </summary>
    /// <param name="groupName">The name of the Amazon EC2 Auto Scaling group.</param>
    /// <returns>A list of Amazon EC2 Auto Scaling groups.</returns>
    public async Task<List<AutoScalingGroup>?> DescribeAutoScalingGroupsAsync(
        string groupName)
    {
        var groupList = new List<string>
            {
                groupName,
            };

        var request = new DescribeAutoScalingGroupsRequest
        {
            AutoScalingGroupNames = groupList,
        };

        var response = await _amazonAutoScaling.DescribeAutoScalingGroupsAsync(request);
        var groups = response.AutoScalingGroups;

        return groups;
    }


    /// <summary>
    /// Delete an Auto Scaling group.
    /// </summary>
    /// <param name="groupName">The name of the Amazon EC2 Auto Scaling group.</param>
    /// <returns>A Boolean value indicating the success of the action.</returns>
    public async Task<bool> DeleteAutoScalingGroupAsync(
        string groupName)
    {
        var deleteAutoScalingGroupRequest = new DeleteAutoScalingGroupRequest
        {
            AutoScalingGroupName = groupName,
            ForceDelete = true,
        };

        var response = await _amazonAutoScaling.DeleteAutoScalingGroupAsync(deleteAutoScalingGroupRequest);
        if (response.HttpStatusCode == System.Net.HttpStatusCode.OK)
        {
            Console.WriteLine($"You successfully deleted {groupName}");
            return true;
        }

        Console.WriteLine($"Couldn't delete {groupName}.");
        return false;
    }


    /// <summary>
    /// Disable the collection of metric data for an Amazon EC2 Auto Scaling
    /// group.
    /// </summary>
    /// <param name="groupName">The name of the Auto Scaling group.</param>
    /// <returns>A Boolean value that indicates the success or failure of
    /// the operation.</returns>
    public async Task<bool> DisableMetricsCollectionAsync(string groupName)
    {
        var request = new DisableMetricsCollectionRequest
        {
            AutoScalingGroupName = groupName,
        };

        var response = await _amazonAutoScaling.DisableMetricsCollectionAsync(request);
        return response.HttpStatusCode == System.Net.HttpStatusCode.OK;
    }


    /// <summary>
    /// Enable the collection of metric data for an Auto Scaling group.
    /// </summary>
    /// <param name="groupName">The name of the Auto Scaling group.</param>
    /// <returns>A Boolean value indicating the success of the action.</returns>
    public async Task<bool> EnableMetricsCollectionAsync(string groupName)
    {
        var listMetrics = new List<string>
            {
                "GroupMaxSize",
            };

        var collectionRequest = new EnableMetricsCollectionRequest
        {
            AutoScalingGroupName = groupName,
            Metrics = listMetrics,
            Granularity = "1Minute",
        };

        var response = await _amazonAutoScaling.EnableMetricsCollectionAsync(collectionRequest);
        return response.HttpStatusCode == System.Net.HttpStatusCode.OK;
    }


    /// <summary>
    /// Set the desired capacity of an Auto Scaling group.
    /// </summary>
    /// <param name="groupName">The name of the Auto Scaling group.</param>
    /// <param name="desiredCapacity">The desired capacity for the Auto
    /// Scaling group.</param>
    /// <returns>A Boolean value indicating the success of the action.</returns>
    public async Task<bool> SetDesiredCapacityAsync(
        string groupName,
        int desiredCapacity)
    {
        var capacityRequest = new SetDesiredCapacityRequest
        {
            AutoScalingGroupName = groupName,
            DesiredCapacity = desiredCapacity,
        };

        var response = await _amazonAutoScaling.SetDesiredCapacityAsync(capacityRequest);
        Console.WriteLine($"You have set the DesiredCapacity to {desiredCapacity}.");

        return response.HttpStatusCode == System.Net.HttpStatusCode.OK;
    }


    /// <summary>
    /// Terminate all instances in the Auto Scaling group in preparation for
    /// deleting the group.
    /// </summary>
    /// <param name="instanceId">The instance Id of the instance to terminate.</param>
    /// <returns>A Boolean value that indicates the success or failure of
    /// the operation.</returns>
    public async Task<bool> TerminateInstanceInAutoScalingGroupAsync(
        string instanceId)
    {
        var request = new TerminateInstanceInAutoScalingGroupRequest
        {
            InstanceId = instanceId,
            ShouldDecrementDesiredCapacity = false,
        };

        var response = await _amazonAutoScaling.TerminateInstanceInAutoScalingGroupAsync(request);

        if (response.HttpStatusCode == System.Net.HttpStatusCode.OK)
        {
            Console.WriteLine($"You have terminated the instance: {instanceId}");
            return true;
        }

        Console.WriteLine($"Could not terminate {instanceId}");
        return false;
    }


    /// <summary>
    /// Update the capacity of an Auto Scaling group.
    /// </summary>
    /// <param name="groupName">The name of the Auto Scaling group.</param>
    /// <param name="launchTemplateName">The name of the EC2 launch template.</param>
    /// <param name="maxSize">The maximum number of instances that can be
    /// created for the Auto Scaling group.</param>
    /// <returns>A Boolean value indicating the success of the action.</returns>
    public async Task<bool> UpdateAutoScalingGroupAsync(
        string groupName,
        string launchTemplateName,
        int maxSize)
    {
        var templateSpecification = new LaunchTemplateSpecification
        {
            LaunchTemplateName = launchTemplateName,
        };

        var groupRequest = new UpdateAutoScalingGroupRequest
        {
            MaxSize = maxSize,
            AutoScalingGroupName = groupName,
            LaunchTemplate = templateSpecification,
        };

        var response = await _amazonAutoScaling.UpdateAutoScalingGroupAsync(groupRequest);
        if (response.HttpStatusCode == System.Net.HttpStatusCode.OK)
        {
            Console.WriteLine($"You successfully updated the Auto Scaling group {groupName}.");
            return true;
        }
        else
        {
            return false;
        }
    }

}


namespace AutoScalingActions;

using Amazon.EC2;
using Amazon.EC2.Model;

public class EC2Wrapper
{
    private readonly IAmazonEC2 _amazonEc2;

    /// <summary>
    /// Constructor for the EC2Wrapper class.
    /// </summary>
    /// <param name="amazonEc2">The injected Amazon EC2 client.</param>
    public EC2Wrapper(IAmazonEC2 amazonEc2)
    {
        _amazonEc2 = amazonEc2;
    }

    /// <summary>
    /// Create a new Amazon EC2 launch template.
    /// </summary>
    /// <param name="imageId">The image Id to use for instances launched
    /// using the Amazon EC2 launch template.</param>
    /// <param name="instanceType">The type of EC2 instances to create.</param>
    /// <param name="launchTemplateName">The name of the launch template.</param>
    /// <returns>Returns the TemplateID of the new launch template.</returns>
    public async Task<string> CreateLaunchTemplateAsync(
        string imageId,
        string instanceType,
        string launchTemplateName)
    {
        var request = new CreateLaunchTemplateRequest
        {
            LaunchTemplateData = new RequestLaunchTemplateData
            {
                ImageId = imageId,
                InstanceType = instanceType,
            },
            LaunchTemplateName = launchTemplateName,
        };

        var response = await _amazonEc2.CreateLaunchTemplateAsync(request);

        return response.LaunchTemplate.LaunchTemplateId;
    }

    /// <summary>
    /// Delete an Amazon EC2 launch template.
    /// </summary>
    /// <param name="launchTemplateId">The TemplateId of the launch template to
    /// delete.</param>
    /// <returns>The name of the EC2 launch template that was deleted.</returns>
    public async Task<string> DeleteLaunchTemplateAsync(string launchTemplateId)
    {
        var request = new DeleteLaunchTemplateRequest
        {
            LaunchTemplateId = launchTemplateId,
        };

        var response = await _amazonEc2.DeleteLaunchTemplateAsync(request);
        return response.LaunchTemplate.LaunchTemplateName;
    }

    /// <summary>
    /// Retrieve information about an EC2 launch template.
    /// </summary>
    /// <param name="launchTemplateName">The name of the EC2 launch template.</param>
    /// <returns>A Boolean value that indicates the success or failure of
    /// the operation.</returns>
    public async Task<bool> DescribeLaunchTemplateAsync(string launchTemplateName)
    {
        var request = new DescribeLaunchTemplatesRequest
        {
            LaunchTemplateNames = new List<string> { launchTemplateName, },
        };

        var response = await _amazonEc2.DescribeLaunchTemplatesAsync(request);

        if (response.LaunchTemplates is not null)
        {
            response.LaunchTemplates.ForEach(template =>
            {
                Console.Write($"{template.LaunchTemplateName}\t");
                Console.WriteLine(template.LaunchTemplateId);
            });

            return true;
        }

        return false;
    }

    /// <summary>
    /// Retrieve the availability zones for the current region.
    /// </summary>
    /// <returns>A collection of availability zones.</returns>
    public async Task<List<AvailabilityZone>> ListAvailabilityZonesAsync()
    {
        var response = await _amazonEc2.DescribeAvailabilityZonesAsync(
            new DescribeAvailabilityZonesRequest());

        return response.AvailabilityZones;
    }
}


namespace AutoScalingActions;

using Amazon.CloudWatch;
using Amazon.CloudWatch.Model;

/// <summary>
/// Contains methods to access Amazon CloudWatch metrics for the
/// Amazon EC2 Auto Scaling basics scenario.
/// </summary>
public class CloudWatchWrapper
{
    private readonly IAmazonCloudWatch _amazonCloudWatch;

    /// <summary>
    /// Constructor for the CloudWatchWrapper.
    /// </summary>
    /// <param name="amazonCloudWatch">The injected CloudWatch client.</param>
    public CloudWatchWrapper(IAmazonCloudWatch amazonCloudWatch)
    {
        _amazonCloudWatch = amazonCloudWatch;
    }

    /// <summary>
    /// Retrieve the metrics information collection for the Auto Scaling group.
    /// </summary>
    /// <param name="groupName">The name of the Auto Scaling group.</param>
    /// <returns>A list of Metrics collected for the Auto Scaling group.</returns>
    public async Task<List<Amazon.CloudWatch.Model.Metric>> GetCloudWatchMetricsAsync(string groupName)
    {
        var filter = new DimensionFilter
        {
            Name = "AutoScalingGroupName",
            Value = $"{groupName}",
        };

        var request = new ListMetricsRequest
        {
            MetricName = "AutoScalingGroupName",
            Dimensions = new List<DimensionFilter> { filter },
            Namespace = "AWS/AutoScaling",
        };

        var response = await _amazonCloudWatch.ListMetricsAsync(request);

        return response.Metrics;
    }

    /// <summary>
    /// Retrieve the metric data collected for an Amazon EC2 Auto Scaling group.
    /// </summary>
    /// <param name="groupName">The name of the Amazon EC2 Auto Scaling group.</param>
    /// <returns>A list of data points.</returns>
    public async Task<List<Datapoint>> GetMetricStatisticsAsync(string groupName)
    {
        var metricDimensions = new List<Dimension>
            {
                new Dimension
                {
                    Name = "AutoScalingGroupName",
                    Value = $"{groupName}",
                },
            };

        // The start time will be yesterday.
        var startTime = DateTime.UtcNow.AddDays(-1);

        var request = new GetMetricStatisticsRequest
        {
            MetricName = "AutoScalingGroupName",
            Dimensions = metricDimensions,
            Namespace = "AWS/AutoScaling",
            Period = 60, // 60 seconds.
            Statistics = new List<string>() { "Minimum" },
            StartTimeUtc = startTime,
            EndTimeUtc = DateTime.UtcNow,
        };

        var response = await _amazonCloudWatch.GetMetricStatisticsAsync(request);

        return response.Datapoints;
    }

}

//! Routine which demonstrates using an Auto Scaling group
//! to manage Amazon EC2 instances.
/*!
  \sa groupsAndInstancesScenario()
  \param clientConfig: AWS client configuration.
  \return bool: Successful completion.
 */
bool AwsDoc::AutoScaling::groupsAndInstancesScenario(
        const Aws::Client::ClientConfiguration &clientConfig) {
    Aws::String templateName;
    Aws::EC2::EC2Client ec2Client(clientConfig);

    std::cout << std::setfill('*') << std::setw(ASTERISK_FILL_WIDTH) << " "
              << std::endl;
    std::cout
            << "Welcome to the Amazon Elastic Compute Cloud (Amazon EC2) Auto Scaling "
            << "demo for managing groups and instances." << std::endl;
    std::cout << std::setfill('*') << std::setw(ASTERISK_FILL_WIDTH) << " \n"
              << std::endl;

    std::cout << "This example requires an EC2 launch template." << std::endl;
    if (askYesNoQuestion(
            "Would you like to use an existing EC2 launch template (y/n)?  ")) {

        // 1. Specify the name of an existing EC2 launch template.
        templateName = askQuestion(
                "Enter the name of the existing EC2 launch template.  ");

        Aws::EC2::Model::DescribeLaunchTemplatesRequest request;
        request.AddLaunchTemplateNames(templateName);
        Aws::EC2::Model::DescribeLaunchTemplatesOutcome outcome =
                ec2Client.DescribeLaunchTemplates(request);

        if (outcome.IsSuccess()) {
            std::cout << "Validated the EC2 launch template '" << templateName
                      << "' exists by calling DescribeLaunchTemplate." << std::endl;
        }
        else {
            std::cerr << "Error validating the existence of the launch template. "
                      << outcome.GetError().GetMessage()
                      << std::endl;
        }
    }
    else { // 2.  Or create a new EC2 launch template.
        templateName = askQuestion("Enter the name for a new EC2 launch template: ");

        Aws::EC2::Model::CreateLaunchTemplateRequest request;
        request.SetLaunchTemplateName(templateName);

        Aws::EC2::Model::RequestLaunchTemplateData requestLaunchTemplateData;
        requestLaunchTemplateData.SetInstanceType(EC2_LAUNCH_TEMPLATE_INSTANCE_TYPE);
        requestLaunchTemplateData.SetImageId(EC2_LAUNCH_TEMPLATE_IMAGE_ID);

        request.SetLaunchTemplateData(requestLaunchTemplateData);

        Aws::EC2::Model::CreateLaunchTemplateOutcome outcome =
                ec2Client.CreateLaunchTemplate(request);

        if (outcome.IsSuccess()) {
            std::cout << "The EC2 launch template '" << templateName << " was created."
                      << std::endl;
        }
        else if (outcome.GetError().GetExceptionName() ==
                 "InvalidLaunchTemplateName.AlreadyExistsException") {
            std::cout << "The EC2 template '" << templateName << "' already exists"
                      << std::endl;
        }
        else {
            std::cerr << "Error with EC2::CreateLaunchTemplate. "
                      << outcome.GetError().GetMessage()
                      << std::endl;
        }
    }
    Aws::AutoScaling::AutoScalingClient autoScalingClient(clientConfig);
    std::cout << "Let's create an Auto Scaling group." << std::endl;
    Aws::String groupName = askQuestion(
            "Enter a name for the Auto Scaling group:  ");
    // 3. Retrieve a list of EC2 Availability Zones.
    Aws::Vector<Aws::EC2::Model::AvailabilityZone> availabilityZones;
    {
        Aws::EC2::Model::DescribeAvailabilityZonesRequest request;

        Aws::EC2::Model::DescribeAvailabilityZonesOutcome outcome =
                ec2Client.DescribeAvailabilityZones(request);

        if (outcome.IsSuccess()) {
            std::cout
                    << "EC2 instances can be created in the following Availability Zones:"
                    << std::endl;

            availabilityZones = outcome.GetResult().GetAvailabilityZones();
            for (size_t i = 0; i < availabilityZones.size(); ++i) {
                std::cout << "   " << i + 1 << ".  "
                          << availabilityZones[i].GetZoneName() << std::endl;
            }
        }
        else {
            std::cerr << "Error with EC2::DescribeAvailabilityZones. "
                      << outcome.GetError().GetMessage()
                      << std::endl;
            cleanupResources("", templateName, autoScalingClient, ec2Client);
            return false;
        }
    }

    int availabilityZoneChoice = askQuestionForIntRange(
            "Choose an Availability Zone:  ", 1,
            static_cast<int>(availabilityZones.size()));
    // 4. Create an Auto Scaling group with the specified Availability Zone.
    {
        Aws::AutoScaling::Model::CreateAutoScalingGroupRequest request;
        request.SetAutoScalingGroupName(groupName);
        Aws::Vector<Aws::String> availabilityGroupZones;
        availabilityGroupZones.push_back(
                availabilityZones[availabilityZoneChoice - 1].GetZoneName());
        request.SetAvailabilityZones(availabilityGroupZones);
        request.SetMaxSize(1);
        request.SetMinSize(1);

        Aws::AutoScaling::Model::LaunchTemplateSpecification launchTemplateSpecification;
        launchTemplateSpecification.SetLaunchTemplateName(templateName);
        request.SetLaunchTemplate(launchTemplateSpecification);

        Aws::AutoScaling::Model::CreateAutoScalingGroupOutcome outcome =
                autoScalingClient.CreateAutoScalingGroup(request);

        if (outcome.IsSuccess()) {
            std::cout << "Created Auto Scaling group '" << groupName << "'..."
                      << std::endl;
        }
        else if (outcome.GetError().GetErrorType() ==
                 Aws::AutoScaling::AutoScalingErrors::ALREADY_EXISTS_FAULT) {
            std::cout << "Auto Scaling group '" << groupName << "' already exists."
                      << std::endl;
        }
        else {
            std::cerr << "Error with AutoScaling::CreateAutoScalingGroup. "
                      << outcome.GetError().GetMessage()
                      << std::endl;
            cleanupResources("", templateName, autoScalingClient, ec2Client);
            return false;
        }
    }

    Aws::Vector<Aws::AutoScaling::Model::AutoScalingGroup> autoScalingGroups;
    if (AwsDoc::AutoScaling::describeGroup(groupName, autoScalingGroups,
                                           autoScalingClient)) {
        std::cout << "Here is the Auto Scaling group description." << std::endl;
        if (!autoScalingGroups.empty()) {
            logAutoScalingGroupInfo(autoScalingGroups);
        }
    }
    else {
        cleanupResources(groupName, templateName, autoScalingClient, ec2Client);
        return false;
    }

    std::cout
            << "Waiting for the EC2 instance in the Auto Scaling group to become active..."
            << std::endl;
    if (!waitForInstances(groupName, autoScalingGroups, autoScalingClient)) {
        cleanupResources(groupName, templateName, autoScalingClient, ec2Client);
        return false;
    }

    bool enableMetrics = askYesNoQuestion(
            "Do you want to collect metrics about the A"
            "Auto Scaling group during this demo (y/n)?  ");
    // 7. Optionally enable metrics collection for the Auto Scaling group.
    if (enableMetrics) {
        Aws::AutoScaling::Model::EnableMetricsCollectionRequest request;
        request.SetAutoScalingGroupName(groupName);

        request.AddMetrics("GroupMinSize");
        request.AddMetrics("GroupMaxSize");
        request.AddMetrics("GroupDesiredCapacity");
        request.AddMetrics("GroupInServiceInstances");
        request.AddMetrics("GroupTotalInstances");
        request.SetGranularity("1Minute");

        Aws::AutoScaling::Model::EnableMetricsCollectionOutcome outcome =
                autoScalingClient.EnableMetricsCollection(request);
        if (outcome.IsSuccess()) {
            std::cout << "Auto Scaling metrics have been enabled."
                      << std::endl;
        }
        else {
            std::cerr << "Error with AutoScaling::EnableMetricsCollection. "
                      << outcome.GetError().GetMessage()
                      << std::endl;
            cleanupResources(groupName, templateName, autoScalingClient, ec2Client);
            return false;
        }
    }

    std::cout << "Let's update the maximum number of EC2 instances in '" << groupName <<
              "' from 1 to 3." << std::endl;
    askQuestion("Press enter to continue:  ", alwaysTrueTest);
    // 8. Update the Auto Scaling group, setting a new maximum size.
    {
        Aws::AutoScaling::Model::UpdateAutoScalingGroupRequest request;
        request.SetAutoScalingGroupName(groupName);
        request.SetMaxSize(3);

        Aws::AutoScaling::Model::UpdateAutoScalingGroupOutcome outcome =
                autoScalingClient.UpdateAutoScalingGroup(request);

        if (!outcome.IsSuccess()) {
            std::cerr << "Error with AutoScaling::UpdateAutoScalingGroup. "
                      << outcome.GetError().GetMessage()
                      << std::endl;
            cleanupResources(groupName, templateName, autoScalingClient, ec2Client);
            return false;
        }
    }

    if (AwsDoc::AutoScaling::describeGroup(groupName, autoScalingGroups,
                                           autoScalingClient)) {
        if (!autoScalingGroups.empty()) {
            const auto &instances = autoScalingGroups[0].GetInstances();
            std::cout
                    << "The group still has one running EC2 instance, but it can have up to 3.\n"
                    << std::endl;
            logAutoScalingGroupInfo(autoScalingGroups);
        }
        else {
            std::cerr
                    << "No EC2 launch groups were retrieved from DescribeGroup request."
                    << std::endl;
            cleanupResources(groupName, templateName, autoScalingClient, ec2Client);
            return false;
        }
    }

    std::cout << "\n" << std::setfill('*') << std::setw(ASTERISK_FILL_WIDTH) << "\n"
              << std::endl;
    std::cout << "Let's update the desired capacity in '" << groupName <<
              "' from 1 to 2." << std::endl;
    askQuestion("Press enter to continue:  ", alwaysTrueTest);
    //  9. Update the Auto Scaling group, setting a new desired capacity.
    {
        Aws::AutoScaling::Model::SetDesiredCapacityRequest request;
        request.SetAutoScalingGroupName(groupName);
        request.SetDesiredCapacity(2);

        Aws::AutoScaling::Model::SetDesiredCapacityOutcome outcome =
                autoScalingClient.SetDesiredCapacity(request);

        if (!outcome.IsSuccess()) {
            std::cerr << "Error with AutoScaling::SetDesiredCapacityRequest. "
                      << outcome.GetError().GetMessage()
                      << std::endl;
            cleanupResources(groupName, templateName, autoScalingClient, ec2Client);
            return false;
        }
    }

    if (AwsDoc::AutoScaling::describeGroup(groupName, autoScalingGroups,
                                           autoScalingClient)) {
        if (!autoScalingGroups.empty()) {
            std::cout
                    << "Here is the current state of the group." << std::endl;
            logAutoScalingGroupInfo(autoScalingGroups);
        }
        else {
            std::cerr
                    << "No EC2 launch groups were retrieved from DescribeGroup request."
                    << std::endl;
            cleanupResources(groupName, templateName, autoScalingClient, ec2Client);
            return false;
        }
    }

    std::cout << "Waiting for the new EC2 instance to start..." << std::endl;
    waitForInstances(groupName, autoScalingGroups, autoScalingClient);

    std::cout << "\n" << std::setfill('*') << std::setw(ASTERISK_FILL_WIDTH) << "\n"
              << std::endl;

    std::cout << "Let's terminate one of the EC2 instances in " << groupName << "."
              << std::endl;
    std::cout << "Because the desired capacity is 2, another EC2 instance will start "
              << "to replace the terminated EC2 instance."
              << std::endl;
    std::cout << "The currently running EC2 instances are:" << std::endl;

    if (autoScalingGroups.empty()) {
        std::cerr << "Error describing groups. No groups returned." << std::endl;
        cleanupResources(groupName, templateName, autoScalingClient, ec2Client);
        return false;
    }

    int instanceNumber = 1;
    Aws::Vector<Aws::String> instanceIDs = instancesToInstanceIDs(
            autoScalingGroups[0].GetInstances());
    for (const Aws::String &instanceID: instanceIDs) {
        std::cout << "   " << instanceNumber << ". " << instanceID << std::endl;
        ++instanceNumber;
    }

    instanceNumber = askQuestionForIntRange("Which EC2 instance do you want to stop? ",
                                            1,
                                            static_cast<int>(instanceIDs.size()));

    // 10. Terminate an EC2 instance in the Auto Scaling group.
    {
        Aws::AutoScaling::Model::TerminateInstanceInAutoScalingGroupRequest request;
        request.SetInstanceId(instanceIDs[instanceNumber - 1]);
        request.SetShouldDecrementDesiredCapacity(false);

        Aws::AutoScaling::Model::TerminateInstanceInAutoScalingGroupOutcome outcome =
                autoScalingClient.TerminateInstanceInAutoScalingGroup(request);

        if (outcome.IsSuccess()) {
            std::cout << "Waiting for EC2 instance with ID '"
                      << instanceIDs[instanceNumber - 1] << "' to terminate..."
                      << std::endl;
        }
        else {
            std::cerr << "Error with AutoScaling::TerminateInstanceInAutoScalingGroup. "
                      << outcome.GetError().GetMessage()
                      << std::endl;
            cleanupResources(groupName, templateName, autoScalingClient, ec2Client);
            return false;
        }
    }

    waitForInstances(groupName, autoScalingGroups, autoScalingClient);

    std::cout << "\n" << std::setfill('*') << std::setw(ASTERISK_FILL_WIDTH) << "\n"
              << std::endl;
    std::cout << "Let's get a report of scaling activities for EC2 launch group '"
              << groupName << "'."
              << std::endl;
    askQuestion("Press enter to continue:  ", alwaysTrueTest);
    // 11. Get a description of activities for the Auto Scaling group.
    {
        Aws::AutoScaling::Model::DescribeScalingActivitiesRequest request;
        request.SetAutoScalingGroupName(groupName);

        Aws::Vector<Aws::AutoScaling::Model::Activity> allActivities;
        Aws::String nextToken; // Used for pagination;
        do {
            if (!nextToken.empty()) {
                request.SetNextToken(nextToken);
            }
            Aws::AutoScaling::Model::DescribeScalingActivitiesOutcome outcome =
                    autoScalingClient.DescribeScalingActivities(request);

            if (outcome.IsSuccess()) {
                const Aws::Vector<Aws::AutoScaling::Model::Activity> &activities =
                        outcome.GetResult().GetActivities();
                allActivities.insert(allActivities.end(), activities.begin(), activities.end());
                nextToken  = outcome.GetResult().GetNextToken();
            }
            else {
                std::cerr << "Error with AutoScaling::DescribeScalingActivities. "
                          << outcome.GetError().GetMessage()
                          << std::endl;
                cleanupResources(groupName, templateName, autoScalingClient, ec2Client);
                return false;
            }
        } while (!nextToken.empty());

        std::cout << "Found " << allActivities.size() << " activities."
                  << std::endl;
        std::cout << "Activities are ordered with the most recent first."
                  << std::endl;
        for (const Aws::AutoScaling::Model::Activity &activity: allActivities) {
            std::cout << activity.GetDescription() << std::endl;
            std::cout << activity.GetDetails() << std::endl;
        }
    }

    if (enableMetrics) {
        if (!logAutoScalingMetrics(groupName, clientConfig)) {
            cleanupResources(groupName, templateName, autoScalingClient, ec2Client);
            return false;
        }
    }

    std::cout << "Let's  clean up." << std::endl;
    askQuestion("Press enter to continue:  ", alwaysTrueTest);

    // 13. Disable metrics collection if enabled.
    if (enableMetrics) {
        Aws::AutoScaling::Model::DisableMetricsCollectionRequest request;
        request.SetAutoScalingGroupName(groupName);

        Aws::AutoScaling::Model::DisableMetricsCollectionOutcome outcome =
                autoScalingClient.DisableMetricsCollection(request);

        if (outcome.IsSuccess()) {
            std::cout << "Metrics collection has been disabled." << std::endl;
        }
        else {
            std::cerr << "Error with AutoScaling::DisableMetricsCollection. "
                      << outcome.GetError().GetMessage()
                      << std::endl;
            cleanupResources(groupName, templateName, autoScalingClient, ec2Client);
            return false;
        }
    }

    return cleanupResources(groupName, templateName, autoScalingClient, ec2Client);
}

//! Routine which waits for EC2 instances in an Auto Scaling group to
//! complete startup or shutdown.
/*!
 \sa waitForInstances()
 \param groupName: An Auto Scaling group name.
 \param autoScalingGroups: Vector to receive 'AutoScalingGroup' records.
 \param client: 'AutoScalingClient' instance.
 \return bool: Successful completion.
 */
bool AwsDoc::AutoScaling::waitForInstances(const Aws::String &groupName,
                                           Aws::Vector<Aws::AutoScaling::Model::AutoScalingGroup> &autoScalingGroups,
                                           const Aws::AutoScaling::AutoScalingClient &client) {
    bool ready = false;
    const std::vector<Aws::String> READY_STATES = {"InService", "Terminated"};

    int count = 0;
    int desiredCapacity = 0;
    std::this_thread::sleep_for(std::chrono::seconds(4));
    while (!ready) {
        if (WAIT_FOR_INSTANCES_TIMEOUT < count) {
            std::cerr << "Wait for instance timed out." << std::endl;
            return false;
        }

        std::this_thread::sleep_for(std::chrono::seconds(1));
        ++count;
        if (!describeGroup(groupName, autoScalingGroups, client)) {
            return false;
        }
        Aws::Vector<Aws::String> instanceIDs;
        if (!autoScalingGroups.empty()) {
            instanceIDs = instancesToInstanceIDs(autoScalingGroups[0].GetInstances());
            desiredCapacity = autoScalingGroups[0].GetDesiredCapacity();
        }

        if (instanceIDs.empty()) {
            if (desiredCapacity == 0) {
                break;
            }
            else {
                if ((count % 5) == 0) {
                    std::cout << "No instance IDs returned for group." << std::endl;
                }

                continue;
            }
        }

        // 6.  Check lifecycle state of the instances using DescribeAutoScalingInstances.
        Aws::AutoScaling::Model::DescribeAutoScalingInstancesRequest request;
        request.SetInstanceIds(instanceIDs);

        Aws::AutoScaling::Model::DescribeAutoScalingInstancesOutcome outcome =
                client.DescribeAutoScalingInstances(request);

        if (outcome.IsSuccess()) {
            const Aws::Vector<Aws::AutoScaling::Model::AutoScalingInstanceDetails> &instancesDetails =
                    outcome.GetResult().GetAutoScalingInstances();
            ready = instancesDetails.size() >= desiredCapacity;
            for (const Aws::AutoScaling::Model::AutoScalingInstanceDetails &details: instancesDetails) {
                if (!stringInVector(details.GetLifecycleState(), READY_STATES)) {
                    ready = false;
                    break;
                }
            }
            // Log the status while waiting.
            if (((count % 5) == 1) || ready) {
                logInstancesLifecycleState(instancesDetails);
            }
        }
        else {
            std::cerr << "Error with AutoScaling::DescribeAutoScalingInstances. "
                      << outcome.GetError().GetMessage()
                      << std::endl;
            return false;
        }
    }

    if (!describeGroup(groupName, autoScalingGroups, client)) {
        return false;
    }

    return true;
}

//! Routine to cleanup resources created in 'groupsAndInstancesScenario'.
/*!
 \sa cleanupResources()
 \param groupName: Optional Auto Scaling group name.
 \param templateName: Optional EC2 launch template name.
 \param autoScalingClient: 'AutoScalingClient' instance.
 \param ec2Client: 'EC2Client' instance.
\return bool: Successful completion.
 */
bool AwsDoc::AutoScaling::cleanupResources(const Aws::String &groupName,
                                           const Aws::String &templateName,
                                           const Aws::AutoScaling::AutoScalingClient &autoScalingClient,
                                           const Aws::EC2::EC2Client &ec2Client) {
    bool result = true;

    // 14. Delete the Auto Scaling group.
    if (!groupName.empty() &&
        (askYesNoQuestion(
                Aws::String("Delete the Auto Scaling group '") + groupName +
                "'  (y/n)?"))) {
        {
            Aws::AutoScaling::Model::UpdateAutoScalingGroupRequest request;
            request.SetAutoScalingGroupName(groupName);
            request.SetMinSize(0);
            request.SetDesiredCapacity(0);

            Aws::AutoScaling::Model::UpdateAutoScalingGroupOutcome outcome =
                    autoScalingClient.UpdateAutoScalingGroup(request);

            if (outcome.IsSuccess()) {
                std::cout
                        << "The minimum size and desired capacity of the Auto Scaling group "
                        << "was set to zero before terminating the instances."
                        << std::endl;
            }
            else {
                std::cerr << "Error with AutoScaling::UpdateAutoScalingGroup. "
                          << outcome.GetError().GetMessage() << std::endl;
                result = false;
            }
        }

        Aws::Vector<Aws::AutoScaling::Model::AutoScalingGroup> autoScalingGroups;
        if (AwsDoc::AutoScaling::describeGroup(groupName, autoScalingGroups,
                                               autoScalingClient)) {
            if (!autoScalingGroups.empty()) {
                Aws::Vector<Aws::String> instanceIDs = instancesToInstanceIDs(
                        autoScalingGroups[0].GetInstances());
                for (const Aws::String &instanceID: instanceIDs) {
                    Aws::AutoScaling::Model::TerminateInstanceInAutoScalingGroupRequest request;
                    request.SetInstanceId(instanceID);
                    request.SetShouldDecrementDesiredCapacity(true);

                    Aws::AutoScaling::Model::TerminateInstanceInAutoScalingGroupOutcome outcome =
                            autoScalingClient.TerminateInstanceInAutoScalingGroup(
                                    request);

                    if (outcome.IsSuccess()) {
                        std::cout << "Initiating termination of EC2 instance '"
                                  << instanceID << "'." << std::endl;
                    }
                    else {
                        std::cerr
                                << "Error with AutoScaling::TerminateInstanceInAutoScalingGroup. "
                                << outcome.GetError().GetMessage() << std::endl;
                        result = false;
                    }
                }
            }

            std::cout
                    << "Waiting for the EC2 instances to terminate before deleting the "
                    << "Auto Scaling group..." << std::endl;
            waitForInstances(groupName, autoScalingGroups, autoScalingClient);
        }

        {
            Aws::AutoScaling::Model::DeleteAutoScalingGroupRequest request;
            request.SetAutoScalingGroupName(groupName);

            Aws::AutoScaling::Model::DeleteAutoScalingGroupOutcome outcome =
                    autoScalingClient.DeleteAutoScalingGroup(request);

            if (outcome.IsSuccess()) {
                std::cout << "Auto Scaling group '" << groupName << "' was deleted."
                          << std::endl;
            }
            else {
                std::cerr << "Error with AutoScaling::DeleteAutoScalingGroup. "
                          << outcome.GetError().GetMessage()
                          << std::endl;
                result = false;
            }
        }
    }

    // 15. Delete the EC2 launch template.
    if (!templateName.empty() && (askYesNoQuestion(
            Aws::String("Delete the EC2 launch template '") + templateName +
            "' (y/n)?"))) {
        Aws::EC2::Model::DeleteLaunchTemplateRequest request;
        request.SetLaunchTemplateName(templateName);

        Aws::EC2::Model::DeleteLaunchTemplateOutcome outcome =
                ec2Client.DeleteLaunchTemplate(request);

        if (outcome.IsSuccess()) {
            std::cout << "EC2 launch template '" << templateName << "' was deleted."
                      << std::endl;
        }
        else {
            std::cerr << "Error with EC2::DeleteLaunchTemplate. "
                      << outcome.GetError().GetMessage()
                      << std::endl;
            result = false;
        }
    }

    return result;
}

//! Routine which retrieves Auto Scaling group descriptions.
/*!
 \sa describeGroup()
 \param groupName: An Auto Scaling group name.
 \param autoScalingGroups: Vector to receive 'AutoScalingGroup' records.
 \param client: 'AutoScalingClient' instance.
 \return bool: Successful completion.
 */
bool AwsDoc::AutoScaling::describeGroup(const Aws::String &groupName,
                                        Aws::Vector<Aws::AutoScaling::Model::AutoScalingGroup> &autoScalingGroup,
                                        const Aws::AutoScaling::AutoScalingClient &client) {
    // 5. Retrieve a description of the Auto Scaling group.
    Aws::AutoScaling::Model::DescribeAutoScalingGroupsRequest request;
    Aws::Vector<Aws::String> groupNames;
    groupNames.push_back(groupName);
    request.SetAutoScalingGroupNames(groupNames);

    Aws::AutoScaling::Model::DescribeAutoScalingGroupsOutcome outcome =
            client.DescribeAutoScalingGroups(request);

    if (outcome.IsSuccess()) {
        autoScalingGroup = outcome.GetResult().GetAutoScalingGroups();
    }
    else {
        std::cerr << "Error with AutoScaling::DescribeAutoScalingGroups. "
                  << outcome.GetError().GetMessage()
                  << std::endl;
    }

    return outcome.IsSuccess();
}

/**
 * Before running this SDK for Java (v2) code example, set up your development
 * environment, including your credentials.
 *
 * For more information, see the following documentation:
 *
 * https://docs.aws.amazon.com/sdk-for-java/latest/developer-guide/get-started.html
 *
 * In addition, create a launch template. For more information, see the
 * following topic:
 *
 * https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/ec2-launch-templates.html#create-launch-template
 *
 * This code example performs the following operations:
 * 1. Creates an Auto Scaling group using an AutoScalingWaiter.
 * 2. Gets a specific Auto Scaling group and returns an instance Id value.
 * 3. Describes Auto Scaling with the Id value.
 * 4. Enables metrics collection.
 * 5. Update an Auto Scaling group.
 * 6. Describes Account details.
 * 7. Describe account details"
 * 8. Updates an Auto Scaling group to use an additional instance.
 * 9. Gets the specific Auto Scaling group and gets the number of instances.
 * 10. List the scaling activities that have occurred for the group.
 * 11. Terminates an instance in the Auto Scaling group.
 * 12. Stops the metrics collection.
 * 13. Deletes the Auto Scaling group.
 */

public class AutoScalingScenario {
    public static final String DASHES = new String(new char[80]).replace("\0", "-");

    public static void main(String[] args) throws InterruptedException {
        final String usage = """

                Usage:
                    <groupName> <launchTemplateName> <vpcZoneId>

                Where:
                    groupName - The name of the Auto Scaling group.
                    launchTemplateName - The name of the launch template.\s
                    vpcZoneId - A subnet Id for a virtual private cloud (VPC) where instances in the Auto Scaling group can be created.
                """;

        if (args.length != 3) {
            System.out.println(usage);
            System.exit(1);
        }

        String groupName = args[0];
        String launchTemplateName = args[1];
        String vpcZoneId = args[2];
        AutoScalingClient autoScalingClient = AutoScalingClient.builder()
                .region(Region.US_EAST_1)
                .build();

        System.out.println(DASHES);
        System.out.println("Welcome to the Amazon EC2 Auto Scaling example scenario.");
        System.out.println(DASHES);

        System.out.println(DASHES);
        System.out.println("1. Create an Auto Scaling group named " + groupName);
        createAutoScalingGroup(autoScalingClient, groupName, launchTemplateName, vpcZoneId);
        System.out.println(
                "Wait 1 min for the resources, including the instance. Otherwise, an empty instance Id is returned");
        Thread.sleep(60000);
        System.out.println(DASHES);

        System.out.println(DASHES);
        System.out.println("2. Get Auto Scale group Id value");
        String instanceId = getSpecificAutoScalingGroups(autoScalingClient, groupName);
        if (instanceId.compareTo("") == 0) {
            System.out.println("Error - no instance Id value");
            System.exit(1);
        } else {
            System.out.println("The instance Id value is " + instanceId);
        }
        System.out.println(DASHES);

        System.out.println(DASHES);
        System.out.println("3. Describe Auto Scaling with the Id value " + instanceId);
        describeAutoScalingInstance(autoScalingClient, instanceId);
        System.out.println(DASHES);

        System.out.println(DASHES);
        System.out.println("4. Enable metrics collection " + instanceId);
        enableMetricsCollection(autoScalingClient, groupName);
        System.out.println(DASHES);

        System.out.println(DASHES);
        System.out.println("5. Update an Auto Scaling group to update max size to 3");
        updateAutoScalingGroup(autoScalingClient, groupName, launchTemplateName);
        System.out.println(DASHES);

        System.out.println(DASHES);
        System.out.println("6. Describe Auto Scaling groups");
        describeAutoScalingGroups(autoScalingClient, groupName);
        System.out.println(DASHES);

        System.out.println(DASHES);
        System.out.println("7. Describe account details");
        describeAccountLimits(autoScalingClient);
        System.out.println(
                "Wait 1 min for the resources, including the instance. Otherwise, an empty instance Id is returned");
        Thread.sleep(60000);
        System.out.println(DASHES);

        System.out.println(DASHES);
        System.out.println("8. Set desired capacity to 2");
        setDesiredCapacity(autoScalingClient, groupName);
        System.out.println(DASHES);

        System.out.println(DASHES);
        System.out.println("9. Get the two instance Id values and state");
        getSpecificAutoScalingGroups(autoScalingClient, groupName);
        System.out.println(DASHES);

        System.out.println(DASHES);
        System.out.println("10. List the scaling activities that have occurred for the group");
        describeScalingActivities(autoScalingClient, groupName);
        System.out.println(DASHES);

        System.out.println(DASHES);
        System.out.println("11. Terminate an instance in the Auto Scaling group");
        terminateInstanceInAutoScalingGroup(autoScalingClient, instanceId);
        System.out.println(DASHES);

        System.out.println(DASHES);
        System.out.println("12. Stop the metrics collection");
        disableMetricsCollection(autoScalingClient, groupName);
        System.out.println(DASHES);

        System.out.println(DASHES);
        System.out.println("13. Delete the Auto Scaling group");
        deleteAutoScalingGroup(autoScalingClient, groupName);
        System.out.println(DASHES);

        System.out.println(DASHES);
        System.out.println("The Scenario has successfully completed.");
        System.out.println(DASHES);

        autoScalingClient.close();
    }

    public static void describeScalingActivities(AutoScalingClient autoScalingClient, String groupName) {
        try {
            DescribeScalingActivitiesRequest scalingActivitiesRequest = DescribeScalingActivitiesRequest.builder()
                    .autoScalingGroupName(groupName)
                    .maxRecords(10)
                    .build();

            DescribeScalingActivitiesResponse response = autoScalingClient
                    .describeScalingActivities(scalingActivitiesRequest);
            List<Activity> activities = response.activities();
            for (Activity activity : activities) {
                System.out.println("The activity Id is " + activity.activityId());
                System.out.println("The activity details are " + activity.details());
            }

        } catch (AutoScalingException e) {
            System.err.println(e.awsErrorDetails().errorMessage());
            System.exit(1);
        }
    }

    public static void setDesiredCapacity(AutoScalingClient autoScalingClient, String groupName) {
        try {
            SetDesiredCapacityRequest capacityRequest = SetDesiredCapacityRequest.builder()
                    .autoScalingGroupName(groupName)
                    .desiredCapacity(2)
                    .build();

            autoScalingClient.setDesiredCapacity(capacityRequest);
            System.out.println("You have set the DesiredCapacity to 2");

        } catch (AutoScalingException e) {
            System.err.println(e.awsErrorDetails().errorMessage());
            System.exit(1);
        }
    }

    public static void createAutoScalingGroup(AutoScalingClient autoScalingClient,
            String groupName,
            String launchTemplateName,
            String vpcZoneId) {
        try {
            AutoScalingWaiter waiter = autoScalingClient.waiter();
            LaunchTemplateSpecification templateSpecification = LaunchTemplateSpecification.builder()
                    .launchTemplateName(launchTemplateName)
                    .build();

            CreateAutoScalingGroupRequest request = CreateAutoScalingGroupRequest.builder()
                    .autoScalingGroupName(groupName)
                    .availabilityZones("us-east-1a")
                    .launchTemplate(templateSpecification)
                    .maxSize(1)
                    .minSize(1)
                    .vpcZoneIdentifier(vpcZoneId)
                    .build();

            autoScalingClient.createAutoScalingGroup(request);
            DescribeAutoScalingGroupsRequest groupsRequest = DescribeAutoScalingGroupsRequest.builder()
                    .autoScalingGroupNames(groupName)
                    .build();

            WaiterResponse<DescribeAutoScalingGroupsResponse> waiterResponse = waiter
                    .waitUntilGroupExists(groupsRequest);
            waiterResponse.matched().response().ifPresent(System.out::println);
            System.out.println("Auto Scaling Group created");

        } catch (AutoScalingException e) {
            System.err.println(e.awsErrorDetails().errorMessage());
            System.exit(1);
        }
    }

    public static void describeAutoScalingInstance(AutoScalingClient autoScalingClient, String id) {
        try {
            DescribeAutoScalingInstancesRequest describeAutoScalingInstancesRequest = DescribeAutoScalingInstancesRequest
                    .builder()
                    .instanceIds(id)
                    .build();

            DescribeAutoScalingInstancesResponse response = autoScalingClient
                    .describeAutoScalingInstances(describeAutoScalingInstancesRequest);
            List<AutoScalingInstanceDetails> instances = response.autoScalingInstances();
            for (AutoScalingInstanceDetails instance : instances) {
                System.out.println("The instance lifecycle state is: " + instance.lifecycleState());
            }

        } catch (AutoScalingException e) {
            System.err.println(e.awsErrorDetails().errorMessage());
            System.exit(1);
        }
    }

    public static void describeAutoScalingGroups(AutoScalingClient autoScalingClient, String groupName) {
        try {
            DescribeAutoScalingGroupsRequest groupsRequest = DescribeAutoScalingGroupsRequest.builder()
                    .autoScalingGroupNames(groupName)
                    .maxRecords(10)
                    .build();

            DescribeAutoScalingGroupsResponse response = autoScalingClient.describeAutoScalingGroups(groupsRequest);
            List<AutoScalingGroup> groups = response.autoScalingGroups();
            for (AutoScalingGroup group : groups) {
                System.out.println("*** The service to use for the health checks: " + group.healthCheckType());
            }

        } catch (AutoScalingException e) {
            System.err.println(e.awsErrorDetails().errorMessage());
            System.exit(1);
        }
    }

    public static String getSpecificAutoScalingGroups(AutoScalingClient autoScalingClient, String groupName) {
        try {
            String instanceId = "";
            DescribeAutoScalingGroupsRequest scalingGroupsRequest = DescribeAutoScalingGroupsRequest.builder()
                    .autoScalingGroupNames(groupName)
                    .build();

            DescribeAutoScalingGroupsResponse response = autoScalingClient
                    .describeAutoScalingGroups(scalingGroupsRequest);
            List<AutoScalingGroup> groups = response.autoScalingGroups();
            for (AutoScalingGroup group : groups) {
                System.out.println("The group name is " + group.autoScalingGroupName());
                System.out.println("The group ARN is " + group.autoScalingGroupARN());
                List<Instance> instances = group.instances();

                for (Instance instance : instances) {
                    instanceId = instance.instanceId();
                    System.out.println("The instance id is " + instanceId);
                    System.out.println("The lifecycle state is " + instance.lifecycleState());
                }
            }

            return instanceId;
        } catch (AutoScalingException e) {
            System.err.println(e.awsErrorDetails().errorMessage());
            System.exit(1);
        }
        return "";
    }

    public static void enableMetricsCollection(AutoScalingClient autoScalingClient, String groupName) {
        try {
            EnableMetricsCollectionRequest collectionRequest = EnableMetricsCollectionRequest.builder()
                    .autoScalingGroupName(groupName)
                    .metrics("GroupMaxSize")
                    .granularity("1Minute")
                    .build();

            autoScalingClient.enableMetricsCollection(collectionRequest);
            System.out.println("The enable metrics collection operation was successful");

        } catch (AutoScalingException e) {
            System.err.println(e.awsErrorDetails().errorMessage());
            System.exit(1);
        }
    }

    public static void disableMetricsCollection(AutoScalingClient autoScalingClient, String groupName) {
        try {
            DisableMetricsCollectionRequest disableMetricsCollectionRequest = DisableMetricsCollectionRequest.builder()
                    .autoScalingGroupName(groupName)
                    .metrics("GroupMaxSize")
                    .build();

            autoScalingClient.disableMetricsCollection(disableMetricsCollectionRequest);
            System.out.println("The disable metrics collection operation was successful");

        } catch (AutoScalingException e) {
            System.err.println(e.awsErrorDetails().errorMessage());
            System.exit(1);
        }
    }

    public static void describeAccountLimits(AutoScalingClient autoScalingClient) {
        try {
            DescribeAccountLimitsResponse response = autoScalingClient.describeAccountLimits();
            System.out.println("The max number of auto scaling groups is " + response.maxNumberOfAutoScalingGroups());
            System.out.println("The current number of auto scaling groups is " + response.numberOfAutoScalingGroups());

        } catch (AutoScalingException e) {
            System.err.println(e.awsErrorDetails().errorMessage());
            System.exit(1);
        }
    }

    public static void updateAutoScalingGroup(AutoScalingClient autoScalingClient, String groupName,
            String launchTemplateName) {
        try {
            AutoScalingWaiter waiter = autoScalingClient.waiter();
            LaunchTemplateSpecification templateSpecification = LaunchTemplateSpecification.builder()
                    .launchTemplateName(launchTemplateName)
                    .build();

            UpdateAutoScalingGroupRequest groupRequest = UpdateAutoScalingGroupRequest.builder()
                    .maxSize(3)
                    .autoScalingGroupName(groupName)
                    .launchTemplate(templateSpecification)
                    .build();

            autoScalingClient.updateAutoScalingGroup(groupRequest);
            DescribeAutoScalingGroupsRequest groupsRequest = DescribeAutoScalingGroupsRequest.builder()
                    .autoScalingGroupNames(groupName)
                    .build();

            WaiterResponse<DescribeAutoScalingGroupsResponse> waiterResponse = waiter
                    .waitUntilGroupInService(groupsRequest);
            waiterResponse.matched().response().ifPresent(System.out::println);
            System.out.println("You successfully updated the auto scaling group  " + groupName);

        } catch (AutoScalingException e) {
            System.err.println(e.awsErrorDetails().errorMessage());
            System.exit(1);
        }
    }

    public static void terminateInstanceInAutoScalingGroup(AutoScalingClient autoScalingClient, String instanceId) {
        try {
            TerminateInstanceInAutoScalingGroupRequest request = TerminateInstanceInAutoScalingGroupRequest.builder()
                    .instanceId(instanceId)
                    .shouldDecrementDesiredCapacity(false)
                    .build();

            autoScalingClient.terminateInstanceInAutoScalingGroup(request);
            System.out.println("You have terminated instance " + instanceId);

        } catch (AutoScalingException e) {
            System.err.println(e.awsErrorDetails().errorMessage());
            System.exit(1);
        }
    }

    public static void deleteAutoScalingGroup(AutoScalingClient autoScalingClient, String groupName) {
        try {
            DeleteAutoScalingGroupRequest deleteAutoScalingGroupRequest = DeleteAutoScalingGroupRequest.builder()
                    .autoScalingGroupName(groupName)
                    .forceDelete(true)
                    .build();

            autoScalingClient.deleteAutoScalingGroup(deleteAutoScalingGroupRequest);
            System.out.println("You successfully deleted " + groupName);

        } catch (AutoScalingException e) {
            System.err.println(e.awsErrorDetails().errorMessage());
            System.exit(1);
        }
    }
}

suspend fun main(args: Array<String>) {
    val usage = """
    Usage:
        <groupName> <launchTemplateName> <serviceLinkedRoleARN> <vpcZoneId>

    Where:
        groupName - The name of the Auto Scaling group.
        launchTemplateName - The name of the launch template. 
        serviceLinkedRoleARN - The Amazon Resource Name (ARN) of the service-linked role that the Auto Scaling group uses.
        vpcZoneId - A subnet Id for a virtual private cloud (VPC) where instances in the Auto Scaling group can be created.
    """

    if (args.size != 4) {
        println(usage)
        exitProcess(1)
    }

    val groupName = args[0]
    val launchTemplateName = args[1]
    val serviceLinkedRoleARN = args[2]
    val vpcZoneId = args[3]

    println("**** Create an Auto Scaling group named $groupName")
    createAutoScalingGroup(groupName, launchTemplateName, serviceLinkedRoleARN, vpcZoneId)

    println("Wait 1 min for the resources, including the instance. Otherwise, an empty instance Id is returned")
    delay(60000)

    val instanceId = getSpecificAutoScaling(groupName)
    if (instanceId.compareTo("") == 0) {
        println("Error - no instance Id value")
        exitProcess(1)
    } else {
        println("The instance Id value is $instanceId")
    }

    println("**** Describe Auto Scaling with the Id value $instanceId")
    describeAutoScalingInstance(instanceId)

    println("**** Enable metrics collection $instanceId")
    enableMetricsCollection(groupName)

    println("**** Update an Auto Scaling group to maximum size of 3")
    updateAutoScalingGroup(groupName, launchTemplateName, serviceLinkedRoleARN)

    println("**** Describe all Auto Scaling groups to show the current state of the groups")
    describeAutoScalingGroups(groupName)

    println("**** Describe account details")
    describeAccountLimits()

    println("Wait 1 min for the resources, including the instance. Otherwise, an empty instance Id is returned")
    delay(60000)

    println("**** Set desired capacity to 2")
    setDesiredCapacity(groupName)

    println("**** Get the two instance Id values and state")
    getAutoScalingGroups(groupName)

    println("**** List the scaling activities that have occurred for the group")
    describeScalingActivities(groupName)

    println("**** Terminate an instance in the Auto Scaling group")
    terminateInstanceInAutoScalingGroup(instanceId)

    println("**** Stop the metrics collection")
    disableMetricsCollection(groupName)

    println("**** Delete the Auto Scaling group")
    deleteSpecificAutoScalingGroup(groupName)
}

suspend fun describeAutoScalingGroups(groupName: String) {
    val groupsReques =
        DescribeAutoScalingGroupsRequest {
            autoScalingGroupNames = listOf(groupName)
            maxRecords = 10
        }

    AutoScalingClient { region = "us-east-1" }.use { autoScalingClient ->
        val response = autoScalingClient.describeAutoScalingGroups(groupsReques)
        response.autoScalingGroups?.forEach { group ->
            println("The service to use for the health checks: ${group.healthCheckType}")
        }
    }
}

suspend fun disableMetricsCollection(groupName: String) {
    val disableMetricsCollectionRequest =
        DisableMetricsCollectionRequest {
            autoScalingGroupName = groupName
            metrics = listOf("GroupMaxSize")
        }

    AutoScalingClient { region = "us-east-1" }.use { autoScalingClient ->
        autoScalingClient.disableMetricsCollection(disableMetricsCollectionRequest)
        println("The disable metrics collection operation was successful")
    }
}

suspend fun describeScalingActivities(groupName: String?) {
    val scalingActivitiesRequest =
        DescribeScalingActivitiesRequest {
            autoScalingGroupName = groupName
            maxRecords = 10
        }

    AutoScalingClient { region = "us-east-1" }.use { autoScalingClient ->
        val response = autoScalingClient.describeScalingActivities(scalingActivitiesRequest)
        response.activities?.forEach { activity ->
            println("The activity Id is ${activity.activityId}")
            println("The activity details are ${activity.details}")
        }
    }
}

suspend fun getAutoScalingGroups(groupName: String) {
    val scalingGroupsRequest =
        DescribeAutoScalingGroupsRequest {
            autoScalingGroupNames = listOf(groupName)
        }

    AutoScalingClient { region = "us-east-1" }.use { autoScalingClient ->
        val response = autoScalingClient.describeAutoScalingGroups(scalingGroupsRequest)
        response.autoScalingGroups?.forEach { group ->
            println("The group name is ${group.autoScalingGroupName}")
            println("The group ARN is ${group.autoScalingGroupArn}")
            group.instances?.forEach { instance ->
                println("The instance id is ${instance.instanceId}")
                println("The lifecycle state is " + instance.lifecycleState)
            }
        }
    }
}

suspend fun setDesiredCapacity(groupName: String) {
    val capacityRequest =
        SetDesiredCapacityRequest {
            autoScalingGroupName = groupName
            desiredCapacity = 2
        }

    AutoScalingClient { region = "us-east-1" }.use { autoScalingClient ->
        autoScalingClient.setDesiredCapacity(capacityRequest)
        println("You set the DesiredCapacity to 2")
    }
}

suspend fun updateAutoScalingGroup(
    groupName: String,
    launchTemplateNameVal: String,
    serviceLinkedRoleARNVal: String,
) {
    val templateSpecification =
        LaunchTemplateSpecification {
            launchTemplateName = launchTemplateNameVal
        }

    val groupRequest =
        UpdateAutoScalingGroupRequest {
            maxSize = 3
            serviceLinkedRoleArn = serviceLinkedRoleARNVal
            autoScalingGroupName = groupName
            launchTemplate = templateSpecification
        }

    val groupsRequestWaiter =
        DescribeAutoScalingGroupsRequest {
            autoScalingGroupNames = listOf(groupName)
        }

    AutoScalingClient { region = "us-east-1" }.use { autoScalingClient ->
        autoScalingClient.updateAutoScalingGroup(groupRequest)
        autoScalingClient.waitUntilGroupExists(groupsRequestWaiter)
        println("You successfully updated the Auto Scaling group  $groupName")
    }
}

suspend fun createAutoScalingGroup(
    groupName: String,
    launchTemplateNameVal: String,
    serviceLinkedRoleARNVal: String,
    vpcZoneIdVal: String,
) {
    val templateSpecification =
        LaunchTemplateSpecification {
            launchTemplateName = launchTemplateNameVal
        }

    val request =
        CreateAutoScalingGroupRequest {
            autoScalingGroupName = groupName
            availabilityZones = listOf("us-east-1a")
            launchTemplate = templateSpecification
            maxSize = 1
            minSize = 1
            vpcZoneIdentifier = vpcZoneIdVal
            serviceLinkedRoleArn = serviceLinkedRoleARNVal
        }

    // This object is required for the waiter call.
    val groupsRequestWaiter =
        DescribeAutoScalingGroupsRequest {
            autoScalingGroupNames = listOf(groupName)
        }

    AutoScalingClient { region = "us-east-1" }.use { autoScalingClient ->
        autoScalingClient.createAutoScalingGroup(request)
        autoScalingClient.waitUntilGroupExists(groupsRequestWaiter)
        println("$groupName was created!")
    }
}

suspend fun describeAutoScalingInstance(id: String) {
    val describeAutoScalingInstancesRequest =
        DescribeAutoScalingInstancesRequest {
            instanceIds = listOf(id)
        }

    AutoScalingClient { region = "us-east-1" }.use { autoScalingClient ->
        val response = autoScalingClient.describeAutoScalingInstances(describeAutoScalingInstancesRequest)
        response.autoScalingInstances?.forEach { group ->
            println("The instance lifecycle state is: ${group.lifecycleState}")
        }
    }
}

suspend fun enableMetricsCollection(groupName: String?) {
    val collectionRequest =
        EnableMetricsCollectionRequest {
            autoScalingGroupName = groupName
            metrics = listOf("GroupMaxSize")
            granularity = "1Minute"
        }

    AutoScalingClient { region = "us-east-1" }.use { autoScalingClient ->
        autoScalingClient.enableMetricsCollection(collectionRequest)
        println("The enable metrics collection operation was successful")
    }
}

suspend fun getSpecificAutoScaling(groupName: String): String {
    var instanceId = ""
    val scalingGroupsRequest =
        DescribeAutoScalingGroupsRequest {
            autoScalingGroupNames = listOf(groupName)
        }

    AutoScalingClient { region = "us-east-1" }.use { autoScalingClient ->
        val response = autoScalingClient.describeAutoScalingGroups(scalingGroupsRequest)
        response.autoScalingGroups?.forEach { group ->
            println("The group name is ${group.autoScalingGroupName}")
            println("The group ARN is ${group.autoScalingGroupArn}")

            group.instances?.forEach { instance ->
                instanceId = instance.instanceId.toString()
            }
        }
    }
    return instanceId
}

suspend fun describeAccountLimits() {
    AutoScalingClient { region = "us-east-1" }.use { autoScalingClient ->
        val response = autoScalingClient.describeAccountLimits(DescribeAccountLimitsRequest {})
        println("The max number of Auto Scaling groups is ${response.maxNumberOfAutoScalingGroups}")
        println("The current number of Auto Scaling groups is ${response.numberOfAutoScalingGroups}")
    }
}

suspend fun terminateInstanceInAutoScalingGroup(instanceIdVal: String) {
    val request =
        TerminateInstanceInAutoScalingGroupRequest {
            instanceId = instanceIdVal
            shouldDecrementDesiredCapacity = false
        }

    AutoScalingClient { region = "us-east-1" }.use { autoScalingClient ->
        autoScalingClient.terminateInstanceInAutoScalingGroup(request)
        println("You have terminated instance $instanceIdVal")
    }
}

suspend fun deleteSpecificAutoScalingGroup(groupName: String) {
    val deleteAutoScalingGroupRequest =
        DeleteAutoScalingGroupRequest {
            autoScalingGroupName = groupName
            forceDelete = true
        }

    AutoScalingClient { region = "us-east-1" }.use { autoScalingClient ->
        autoScalingClient.deleteAutoScalingGroup(deleteAutoScalingGroupRequest)
        println("You successfully deleted $groupName")
    }
}

namespace AutoScaling;

use Aws\AutoScaling\AutoScalingClient;
use Aws\CloudWatch\CloudWatchClient;
use Aws\Ec2\Ec2Client;
use AwsUtilities\AWSServiceClass;
use AwsUtilities\RunnableExample;

class GettingStartedWithAutoScaling implements RunnableExample
{
    protected Ec2Client $ec2Client;
    protected AutoScalingClient $autoScalingClient;
    protected AutoScalingService $autoScalingService;
    protected CloudWatchClient $cloudWatchClient;
    protected string $templateName;
    protected string $autoScalingGroupName;
    protected array $role;

    public function runExample()
    {
        echo("\n");
        echo("--------------------------------------\n");
        print("Welcome to the Amazon EC2 Auto Scaling getting started demo using PHP!\n");
        echo("--------------------------------------\n");

        $clientArgs = [
            'region' => 'us-west-2',
            'version' => 'latest',
            'profile' => 'default',
        ];
        $uniqid = uniqid();

        $this->autoScalingClient = new AutoScalingClient($clientArgs);
        $this->autoScalingService = new AutoScalingService($this->autoScalingClient);
        $this->cloudWatchClient = new CloudWatchClient($clientArgs);

        AWSServiceClass::$waitTime = 5;
        AWSServiceClass::$maxWaitAttempts = 20;

        /**
         * Step 0: Create an EC2 launch template that you'll use to create an Auto Scaling group.
         */
        $this->ec2Client = new EC2Client($clientArgs);
        $this->templateName = "example_launch_template_$uniqid";
        $instanceType = "t1.micro";
        $amiId = "ami-0ca285d4c2cda3300";
        $launchTemplate = $this->ec2Client->createLaunchTemplate(
            [
            'LaunchTemplateName' => $this->templateName,
            'LaunchTemplateData' => [
                'InstanceType' => $instanceType,
                'ImageId' => $amiId,
            ]
            ]
        );

        /**
         * Step 1: CreateAutoScalingGroup: pass it the launch template you created in step 0.
         */
        $availabilityZones[] = $this->ec2Client->describeAvailabilityZones([])['AvailabilityZones'][1]['ZoneName'];

        $this->autoScalingGroupName = "demoAutoScalingGroupName_$uniqid";
        $minSize = 1;
        $maxSize = 1;
        $launchTemplateId = $launchTemplate['LaunchTemplate']['LaunchTemplateId'];
        $this->autoScalingService->createAutoScalingGroup(
            $this->autoScalingGroupName,
            $availabilityZones,
            $minSize,
            $maxSize,
            $launchTemplateId
        );

        $this->autoScalingService->waitUntilGroupInService([$this->autoScalingGroupName]);
        $autoScalingGroup = $this->autoScalingService->describeAutoScalingGroups([$this->autoScalingGroupName]);

        /**
         * Step 2: DescribeAutoScalingInstances: show that one instance has launched.
         */
        $instanceIds = [$autoScalingGroup['AutoScalingGroups'][0]['Instances'][0]['InstanceId']];
        $instances = $this->autoScalingService->describeAutoScalingInstances($instanceIds);
        echo "The Auto Scaling group {$this->autoScalingGroupName} was created successfully.\n";
        echo count($instances['AutoScalingInstances']) . " instances were created for the group.\n";
        echo $autoScalingGroup['AutoScalingGroups'][0]['MaxSize'] . " is the max number of instances for the group.\n";

        /**
         * Step 3: EnableMetricsCollection: enable all metrics or a subset.
         */
        $this->autoScalingService->enableMetricsCollection($this->autoScalingGroupName, "1Minute");

        /**
         * Step 4: UpdateAutoScalingGroup: update max size to 3.
         */
        echo "Updating the max number of instances to 3.\n";
        $this->autoScalingService->updateAutoScalingGroup($this->autoScalingGroupName, ['MaxSize' => 3]);

        /**
         * Step 5: DescribeAutoScalingGroups: show the current state of the group.
         */
        $autoScalingGroup = $this->autoScalingService->describeAutoScalingGroups([$this->autoScalingGroupName]);
        echo $autoScalingGroup['AutoScalingGroups'][0]['MaxSize'];
        echo " is the updated max number of instances for the group.\n";

        $limits = $this->autoScalingService->describeAccountLimits();
        echo "Here are your account limits:\n";
        echo "MaxNumberOfAutoScalingGroups: {$limits['MaxNumberOfAutoScalingGroups']}\n";
        echo "MaxNumberOfLaunchConfigurations: {$limits['MaxNumberOfLaunchConfigurations']}\n";
        echo "NumberOfAutoScalingGroups: {$limits['NumberOfAutoScalingGroups']}\n";
        echo "NumberOfLaunchConfigurations: {$limits['NumberOfLaunchConfigurations']}\n";

        /**
         * Step 6: SetDesiredCapacity: set desired capacity to 2.
         */
        $this->autoScalingService->setDesiredCapacity($this->autoScalingGroupName, 2);
        sleep(10); // Wait for the group to start processing the request.
        $this->autoScalingService->waitUntilGroupInService([$this->autoScalingGroupName]);

        /**
         * Step 7: DescribeAutoScalingInstances: show that two instances are launched.
         */
        $autoScalingGroups = $this->autoScalingService->describeAutoScalingGroups([$this->autoScalingGroupName]);
        foreach ($autoScalingGroups['AutoScalingGroups'] as $autoScalingGroup) {
            echo "There is a group named: {$autoScalingGroup['AutoScalingGroupName']}";
            echo "with an ARN of {$autoScalingGroup['AutoScalingGroupARN']}.\n";
            foreach ($autoScalingGroup['Instances'] as $instance) {
                echo "{$autoScalingGroup['AutoScalingGroupName']} has an instance with id of: ";
                echo "{$instance['InstanceId']} and a lifecycle state of: {$instance['LifecycleState']}.\n";
            }
        }

        /**
         * Step 8: TerminateInstanceInAutoScalingGroup: terminate one of the instances in the group.
         */
        $this->autoScalingService->terminateInstanceInAutoScalingGroup($instance['InstanceId'], false);
        do {
            sleep(10);
            $instances = $this->autoScalingService->describeAutoScalingInstances([$instance['InstanceId']]);
        } while (count($instances['AutoScalingInstances']) > 0);
        do {
            sleep(10);
            $autoScalingGroups = $this->autoScalingService->describeAutoScalingGroups([$this->autoScalingGroupName]);
            $instances = $autoScalingGroups['AutoScalingGroups'][0]['Instances'];
        } while (count($instances) < 2);
        $this->autoScalingService->waitUntilGroupInService([$this->autoScalingGroupName]);
        foreach ($autoScalingGroups['AutoScalingGroups'] as $autoScalingGroup) {
            echo "There is a group named: {$autoScalingGroup['AutoScalingGroupName']}";
            echo "with an ARN of {$autoScalingGroup['AutoScalingGroupARN']}.\n";
            foreach ($autoScalingGroup['Instances'] as $instance) {
                echo "{$autoScalingGroup['AutoScalingGroupName']} has an instance with id of: ";
                echo "{$instance['InstanceId']} and a lifecycle state of: {$instance['LifecycleState']}.\n";
            }
        }

        /**
         * Step 9: DescribeScalingActivities: list the scaling activities that have occurred for the group so far.
         */
        $activities = $this->autoScalingService->describeScalingActivities($autoScalingGroup['AutoScalingGroupName']);
        echo "We found " . count($activities['Activities']) . " activities.\n";
        foreach ($activities['Activities'] as $activity) {
            echo "{$activity['ActivityId']} - {$activity['StartTime']} - {$activity['Description']}\n";
        }

        /**
         * Step 10: Use the Amazon CloudWatch API to get and show some metrics collected for the group.
         */
        $metricsNamespace = 'AWS/AutoScaling';
        $metricsDimensions = [
            [
                'Name' => 'AutoScalingGroupName',
                'Value' => $autoScalingGroup['AutoScalingGroupName'],
            ],
        ];
        $metrics = $this->cloudWatchClient->listMetrics(
            [
            'Dimensions' => $metricsDimensions,
            'Namespace' => $metricsNamespace,
            ]
        );
        foreach ($metrics['Metrics'] as $metric) {
            $timespan = 5;
            if ($metric['MetricName'] != 'GroupTotalCapacity' && $metric['MetricName'] != 'GroupMaxSize') {
                continue;
            }
            echo "Over the last $timespan minutes, {$metric['MetricName']} recorded:\n";
            $stats = $this->cloudWatchClient->getMetricStatistics(
                [
                'Dimensions' => $metricsDimensions,
                'EndTime' => time(),
                'StartTime' => time() - (5 * 60),
                'MetricName' => $metric['MetricName'],
                'Namespace' => $metricsNamespace,
                'Period' => 60,
                'Statistics' => ['Sum'],
                ]
            );
            foreach ($stats['Datapoints'] as $stat) {
                echo "{$stat['Timestamp']}: {$stat['Sum']}\n";
            }
        }

        return $instances;
    }

    public function cleanUp()
    {
        /**
         * Step 11: DisableMetricsCollection: disable all metrics.
         */
        $this->autoScalingService->disableMetricsCollection($this->autoScalingGroupName);

        /**
         * Step 12: DeleteAutoScalingGroup: to delete the group you must stop all instances.
         * - UpdateAutoScalingGroup with MinSize=0
         * - TerminateInstanceInAutoScalingGroup for each instance,
         *     specify ShouldDecrementDesiredCapacity=True. Wait for instances to stop.
         * - Now you can delete the group.
         */
        $this->autoScalingService->updateAutoScalingGroup($this->autoScalingGroupName, ['MinSize' => 0]);
        $this->autoScalingService->terminateAllInstancesInAutoScalingGroup($this->autoScalingGroupName);
        $this->autoScalingService->waitUntilGroupInService([$this->autoScalingGroupName]);
        $this->autoScalingService->deleteAutoScalingGroup($this->autoScalingGroupName);

        /**
         * Step 13: Delete launch template.
         */
        $this->ec2Client->deleteLaunchTemplate(
            [
            'LaunchTemplateName' => $this->templateName,
            ]
        );
    }

    public function helloService()
    {
        $autoScalingClient = new AutoScalingClient([
            'region' => 'us-west-2',
            'version' => 'latest',
            'profile' => 'default',
        ]);

        $groups = $autoScalingClient->describeAutoScalingGroups([]);
        var_dump($groups);
    }
}

在命令提示中執行互動式案例。

def run_scenario(as_wrapper, svc_helper):
    logging.basicConfig(level=logging.INFO, format="%(levelname)s: %(message)s")

    print("-" * 88)
    print(
        "Welcome to the Amazon EC2 Auto Scaling demo for managing groups and instances."
    )
    print("-" * 88)

    print(
        "This example requires a launch template that specifies how to create\n"
        "EC2 instances. You can use an existing template or create a new one."
    )
    template_name = q.ask(
        "Enter the name of an existing launch template or press Enter to create a new one: "
    )
    template = None
    if template_name:
        template = svc_helper.get_template(template_name)
    if template is None:
        inst_type = "t1.micro"
        ami_id = "ami-0ca285d4c2cda3300"
        print("Let's create a launch template with the following specifications:")
        print(f"\tInstanceType: {inst_type}")
        print(f"\tAMI ID: {ami_id}")
        template_name = q.ask("Enter a name for the template: ", q.non_empty)
        template = svc_helper.create_template(template_name, inst_type, ami_id)
    print("-" * 88)

    print("Let's create an Auto Scaling group.")
    group_name = q.ask("Enter a name for the group: ", q.non_empty)
    zones = svc_helper.get_availability_zones()
    print("EC2 instances can be created in the following Availability Zones:")
    for index, zone in enumerate(zones):
        print(f"\t{index+1}. {zone}")
    print(f"\t{len(zones)+1}. All zones")
    zone_sel = q.ask(
        "Which zone do you want to use? ", q.is_int, q.in_range(1, len(zones) + 1)
    )
    group_zones = [zones[zone_sel - 1]] if zone_sel <= len(zones) else zones
    print(f"Creating group {group_name}...")
    as_wrapper.create_group(group_name, group_zones, template_name, 1, 1)
    wait(10)
    group = as_wrapper.describe_group(group_name)
    print("Created group:")
    pp(group)
    print("Waiting for instance to start...")
    wait_for_group(group_name, as_wrapper)
    print("-" * 88)

    use_metrics = q.ask(
        "Do you want to collect metrics about Amazon EC2 Auto Scaling during this demo (y/n)? ",
        q.is_yesno,
    )
    if use_metrics:
        as_wrapper.enable_metrics(
            group_name,
            [
                "GroupMinSize",
                "GroupMaxSize",
                "GroupDesiredCapacity",
                "GroupInServiceInstances",
                "GroupTotalInstances",
            ],
        )
        print(f"Metrics enabled for {group_name}.")
    print("-" * 88)

    print(f"Let's update the maximum number of instances in {group_name} from 1 to 3.")
    q.ask("Press Enter when you're ready.")
    as_wrapper.update_group(group_name, MaxSize=3)
    group = as_wrapper.describe_group(group_name)
    print("The group still has one running instance, but can have up to three:")
    print_simplified_group(group)
    print("-" * 88)

    print(f"Let's update the desired capacity of {group_name} from 1 to 2.")
    q.ask("Press Enter when you're ready.")
    as_wrapper.set_desired_capacity(group_name, 2)
    wait(10)
    group = as_wrapper.describe_group(group_name)
    print("Here's the current state of the group:")
    print_simplified_group(group)
    print("-" * 88)
    print("Waiting for the new instance to start...")
    instance_ids = wait_for_group(group_name, as_wrapper)
    print("-" * 88)

    print(f"Let's terminate one of the instances in {group_name}.")
    print("Because the desired capacity is 2, another instance will start.")
    print("The currently running instances are:")
    for index, inst_id in enumerate(instance_ids):
        print(f"\t{index+1}. {inst_id}")
    inst_sel = q.ask(
        "Which instance do you want to stop? ",
        q.is_int,
        q.in_range(1, len(instance_ids) + 1),
    )
    print(f"Stopping {instance_ids[inst_sel-1]}...")
    as_wrapper.terminate_instance(instance_ids[inst_sel - 1], False)
    wait(10)
    group = as_wrapper.describe_group(group_name)
    print(f"Here's the state of {group_name}:")
    print_simplified_group(group)
    print("Waiting for the scaling activities to complete...")
    wait_for_group(group_name, as_wrapper)
    print("-" * 88)

    print(f"Let's get a report of scaling activities for {group_name}.")
    q.ask("Press Enter when you're ready.")
    activities = as_wrapper.describe_scaling_activities(group_name)
    print(
        f"Found {len(activities)} activities.\n"
        f"Activities are ordered with the most recent one first:"
    )
    for act in activities:
        pp(act)
    print("-" * 88)

    if use_metrics:
        print("Let's look at CloudWatch metrics.")
        metric_namespace = "AWS/AutoScaling"
        metric_dimensions = [{"Name": "AutoScalingGroupName", "Value": group_name}]
        print(f"The following metrics are enabled for {group_name}:")
        done = False
        while not done:
            metrics = svc_helper.get_metrics(metric_namespace, metric_dimensions)
            for index, metric in enumerate(metrics):
                print(f"\t{index+1}. {metric.name}")
            print(f"\t{len(metrics)+1}. None")
            metric_sel = q.ask(
                "Which metric do you want to see? ",
                q.is_int,
                q.in_range(1, len(metrics) + 1),
            )
            if metric_sel < len(metrics) + 1:
                span = 5
                metric = metrics[metric_sel - 1]
                print(f"Over the last {span} minutes, {metric.name} recorded:")
                # CloudWatch metric times are in the UTC+0 time zone.
                now = datetime.now(timezone.utc)
                metric_data = svc_helper.get_metric_statistics(
                    metric_dimensions, metric, now - timedelta(minutes=span), now
                )
                pp(metric_data)
                if not q.ask("Do you want to see another metric (y/n)? ", q.is_yesno):
                    done = True
            else:
                done = True

    print(f"Let's clean up.")
    q.ask("Press Enter when you're ready.")
    if use_metrics:
        print(f"Stopping metrics collection for {group_name}.")
        as_wrapper.disable_metrics(group_name)

    print(
        "You must terminate all instances in the group before you can delete the group."
    )
    print("Set minimum size to 0.")
    as_wrapper.update_group(group_name, MinSize=0)
    group = as_wrapper.describe_group(group_name)
    instance_ids = [inst["InstanceId"] for inst in group["Instances"]]
    for inst_id in instance_ids:
        print(f"Stopping {inst_id}.")
        as_wrapper.terminate_instance(inst_id, True)
    print("Waiting for instances to stop...")
    wait_for_instances(instance_ids, as_wrapper)
    print(f"Deleting {group_name}.")
    as_wrapper.delete_group(group_name)
    print("-" * 88)

    if template is not None:
        if q.ask(
            f"Do you want to delete launch template {template_name} used in this demo (y/n)? "
        ):
            svc_helper.delete_template(template_name)
            print("Template deleted.")

    print("\nThanks for watching!")
    print("-" * 88)


if __name__ == "__main__":
    try:
        wrapper = AutoScalingWrapper(boto3.client("autoscaling"))
        helper = ServiceHelper(boto3.client("ec2"), boto3.resource("cloudwatch"))
        run_scenario(wrapper, helper)
    except Exception:
        logging.exception("Something went wrong with the demo!")

定義案例呼叫的函數，以管理啟動範本和指標。這些功能包含 Amazon EC2 和 CloudWatch 操作。

class ServiceHelper:
    """Encapsulates Amazon EC2 and CloudWatch actions for the example."""

    def __init__(self, ec2_client, cloudwatch_resource):
        """
        :param ec2_client: A Boto3 Amazon EC2 client.
        :param cloudwatch_resource: A Boto3 CloudWatch resource.
        """
        self.ec2_client = ec2_client
        self.cloudwatch_resource = cloudwatch_resource

    def get_template(self, template_name):
        """
        Gets a launch template. Launch templates specify configuration for instances
        that are launched by Amazon EC2 Auto Scaling.

        :param template_name: The name of the template to look up.
        :return: The template, if it exists.
        """
        try:
            response = self.ec2_client.describe_launch_templates(
                LaunchTemplateNames=[template_name]
            )
            template = response["LaunchTemplates"][0]
        except ClientError as err:
            if (
                err.response["Error"]["Code"]
                == "InvalidLaunchTemplateName.NotFoundException"
            ):
                logger.warning("Launch template %s does not exist.", template_name)
            else:
                logger.error(
                    "Couldn't verify launch template %s. Here's why: %s: %s",
                    template_name,
                    err.response["Error"]["Code"],
                    err.response["Error"]["Message"],
                )
                raise
        else:
            return template

    def create_template(self, template_name, inst_type, ami_id):
        """
        Creates an Amazon EC2 launch template to use with Amazon EC2 Auto Scaling.

        :param template_name: The name to give to the template.
        :param inst_type: The type of the instance, such as t1.micro.
        :param ami_id: The ID of the Amazon Machine Image (AMI) to use when creating
                       an instance.
        :return: Information about the newly created template.
        """
        try:
            response = self.ec2_client.create_launch_template(
                LaunchTemplateName=template_name,
                LaunchTemplateData={"InstanceType": inst_type, "ImageId": ami_id},
            )
            template = response["LaunchTemplate"]
        except ClientError as err:
            logger.error(
                "Couldn't create launch template %s. Here's why: %s: %s",
                template_name,
                err.response["Error"]["Code"],
                err.response["Error"]["Message"],
            )
            raise
        else:
            return template

    def delete_template(self, template_name):
        """
        Deletes a launch template.

        :param template_name: The name of the template to delete.
        """
        try:
            self.ec2_client.delete_launch_template(LaunchTemplateName=template_name)
        except ClientError as err:
            logger.error(
                "Couldn't delete launch template %s. Here's why: %s: %s",
                template_name,
                err.response["Error"]["Code"],
                err.response["Error"]["Message"],
            )
            raise

    def get_availability_zones(self):
        """
        Gets a list of Availability Zones in the AWS Region of the Amazon EC2 client.

        :return: The list of Availability Zones for the client Region.
        """
        try:
            response = self.ec2_client.describe_availability_zones()
            zones = [zone["ZoneName"] for zone in response["AvailabilityZones"]]
        except ClientError as err:
            logger.error(
                "Couldn't get availability zones. Here's why: %s: %s",
                err.response["Error"]["Code"],
                err.response["Error"]["Message"],
            )
            raise
        else:
            return zones

    def get_metrics(self, namespace, dimensions):
        """
        Gets a list of CloudWatch metrics filtered by namespace and dimensions.

        :param namespace: The namespace of the metrics to look up.
        :param dimensions: The dimensions of the metrics to look up.
        :return: The list of metrics.
        """
        try:
            metrics = list(
                self.cloudwatch_resource.metrics.filter(
                    Namespace=namespace, Dimensions=dimensions
                )
            )
        except ClientError as err:
            logger.error(
                "Couldn't get metrics for %s, %s. Here's why: %s: %s",
                namespace,
                dimensions,
                err.response["Error"]["Code"],
                err.response["Error"]["Message"],
            )
            raise
        else:
            return metrics

    @staticmethod
    def get_metric_statistics(dimensions, metric, start, end):
        """
        Gets statistics for a CloudWatch metric within a specified time span.

        :param dimensions: The dimensions of the metric.
        :param metric: The metric to look up.
        :param start: The start of the time span for retrieved metrics.
        :param end: The end of the time span for retrieved metrics.
        :return: The list of data points found for the specified metric.
        """
        try:
            response = metric.get_statistics(
                Dimensions=dimensions,
                StartTime=start,
                EndTime=end,
                Period=60,
                Statistics=["Sum"],
            )
            data = response["Datapoints"]
        except ClientError as err:
            logger.error(
                "Couldn't get statistics for metric %s. Here's why: %s: %s",
                metric.name,
                err.response["Error"]["Code"],
                err.response["Error"]["Message"],
            )
            raise
        else:
            return data


def print_simplified_group(group):
    """
    Prints a subset of data for an Auto Scaling group.
    """
    print(group["AutoScalingGroupName"])
    print(f"\tLaunch template: {group['LaunchTemplate']['LaunchTemplateName']}")
    print(
        f"\tMin: {group['MinSize']}, Max: {group['MaxSize']}, Desired: {group['DesiredCapacity']}"
    )
    if group["Instances"]:
        print(f"\tInstances:")
        for inst in group["Instances"]:
            print(f"\t\t{inst['InstanceId']}: {inst['LifecycleState']}")


def wait_for_group(group_name, as_wrapper):
    """
    Waits for instances to start or stop in an Auto Scaling group.
    Prints the data for each instance after scaling activities are complete.
    """
    group = as_wrapper.describe_group(group_name)
    instance_ids = [i["InstanceId"] for i in group["Instances"]]
    return wait_for_instances(instance_ids, as_wrapper)


def wait_for_instances(instance_ids, as_wrapper):
    """
    Waits for instances to start or stop in an Auto Scaling group.
    Prints the data for each instance after scaling activities are complete.
    """
    ready = False
    instances = []
    while not ready:
        instances = as_wrapper.describe_instances(instance_ids) if instance_ids else []
        if all([x["LifecycleState"] in ["Terminated", "InService"] for x in instances]):
            ready = True
        else:
            wait(10)
    if instances:
        print(
            f"Here are the details of the instance{'s' if len(instances) > 1 else ''}:"
        )
        for instance in instances:
            pp(instance)
    return instance_ids

[package]
name = "autoscaling-code-examples"
version = "0.1.0"
authors = ["Doug Schwartz <dougsch@amazon.com>", "David Souther <dpsouth@amazon.com>"]
edition = "2021"

# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html

[dependencies]
aws-config = { version = "1.0.1", features = ["behavior-version-latest"] }
aws-sdk-autoscaling = { version = "1.3.0" }
aws-sdk-ec2 = { version = "1.3.0" }
aws-types = { version = "1.0.1" }
tokio = { version = "1.20.1", features = ["full"] }
clap = { version = "~4.4", features = ["derive"] }
tracing-subscriber = { version = "0.3.15", features = ["env-filter"] }
anyhow = "1.0.75"
tracing = "0.1.37"
tokio-stream = "0.1.14"


use std::{collections::BTreeSet, fmt::Display};

use anyhow::anyhow;
use autoscaling_code_examples::scenario::{AutoScalingScenario, ScenarioError};
use tracing::{info, warn};

async fn show_scenario_description(scenario: &AutoScalingScenario, event: &str) {
    let description = scenario.describe_scenario().await;
    info!("DescribeAutoScalingInstances: {event}\n{description}");
}

#[derive(Default, Debug)]
struct Warnings(Vec<String>);

impl Warnings {
    pub fn push(&mut self, warning: &str, error: ScenarioError) {
        let formatted = format!("{warning}: {error}");
        warn!("{formatted}");
        self.0.push(formatted);
    }

    pub fn is_empty(&self) -> bool {
        self.0.is_empty()
    }
}

impl Display for Warnings {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        writeln!(f, "Warnings:")?;
        for warning in &self.0 {
            writeln!(f, "{: >4}- {warning}", "")?;
        }
        Ok(())
    }
}

#[tokio::main]
async fn main() -> Result<(), anyhow::Error> {
    tracing_subscriber::fmt::init();

    let shared_config = aws_config::from_env().load().await;

    let mut warnings = Warnings::default();

    // 1. Create an EC2 launch template that you'll use to create an auto scaling group. Bonus: use SDK with EC2.CreateLaunchTemplate to create the launch template.
    // 2. CreateAutoScalingGroup: pass it the launch template you created in step 0. Give it min/max of 1 instance.
    // 4. EnableMetricsCollection: enable all metrics or a subset.
    let scenario = match AutoScalingScenario::prepare_scenario(&shared_config).await {
        Ok(scenario) => scenario,
        Err(errs) => {
            let err_str = errs
                .into_iter()
                .map(|e| e.to_string())
                .collect::<Vec<String>>()
                .join(", ");
            return Err(anyhow!("Failed to initialize scenario: {err_str}"));
        }
    };

    info!("Prepared autoscaling scenario:\n{scenario}");

    let stable = scenario.wait_for_stable(1).await;
    if let Err(err) = stable {
        warnings.push(
            "There was a problem while waiting for group to be stable",
            err,
        );
    }

    // 3. DescribeAutoScalingInstances: show that one instance has launched.
    show_scenario_description(
        &scenario,
        "show that the group was created and one instance has launched",
    )
    .await;

    // 5. UpdateAutoScalingGroup: update max size to 3.
    let scale_max_size = scenario.scale_max_size(3).await;
    if let Err(err) = scale_max_size {
        warnings.push("There was a problem scaling max size", err);
    }

    // 6. DescribeAutoScalingGroups: the current state of the group
    show_scenario_description(
        &scenario,
        "show the current state of the group after setting max size",
    )
    .await;

    // 7. SetDesiredCapacity: set desired capacity to 2.
    let scale_desired_capacity = scenario.scale_desired_capacity(2).await;
    if let Err(err) = scale_desired_capacity {
        warnings.push("There was a problem setting desired capacity", err);
    }

    //   Wait for a second instance to launch.
    let stable = scenario.wait_for_stable(2).await;
    if let Err(err) = stable {
        warnings.push(
            "There was a problem while waiting for group to be stable",
            err,
        );
    }

    // 8. DescribeAutoScalingInstances: show that two instances are launched.
    show_scenario_description(
        &scenario,
        "show that two instances are launched after setting desired capacity",
    )
    .await;

    let ids_before = scenario
        .list_instances()
        .await
        .map(|v| v.into_iter().collect::<BTreeSet<_>>())
        .unwrap_or_default();

    // 9. TerminateInstanceInAutoScalingGroup: terminate one of the instances in the group.
    let terminate_some_instance = scenario.terminate_some_instance().await;
    if let Err(err) = terminate_some_instance {
        warnings.push("There was a problem replacing an instance", err);
    }

    let wait_after_terminate = scenario.wait_for_stable(1).await;
    if let Err(err) = wait_after_terminate {
        warnings.push(
            "There was a problem waiting after terminating an instance",
            err,
        );
    }

    let wait_scale_up_after_terminate = scenario.wait_for_stable(2).await;
    if let Err(err) = wait_scale_up_after_terminate {
        warnings.push(
            "There was a problem waiting for scale up after terminating an instance",
            err,
        );
    }

    let ids_after = scenario
        .list_instances()
        .await
        .map(|v| v.into_iter().collect::<BTreeSet<_>>())
        .unwrap_or_default();

    let difference = ids_after.intersection(&ids_before).count();
    if !(difference == 1 && ids_before.len() == 2 && ids_after.len() == 2) {
        warnings.push(
            "Before and after set not different",
            ScenarioError::with(format!("{difference}")),
        );
    }

    // 10. DescribeScalingActivities: list the scaling activities that have occurred for the group so far.
    show_scenario_description(
        &scenario,
        "list the scaling activities that have occurred for the group so far",
    )
    .await;

    // 11. DisableMetricsCollection
    let scale_group = scenario.scale_group_to_zero().await;
    if let Err(err) = scale_group {
        warnings.push("There was a problem scaling the group to 0", err);
    }
    show_scenario_description(&scenario, "Scenario scaled to 0").await;

    // 12. DeleteAutoScalingGroup (to delete the group you must stop all instances):
    // 13. Delete LaunchTemplate.
    let clean_scenario = scenario.clean_scenario().await;
    if let Err(errs) = clean_scenario {
        for err in errs {
            warnings.push("There was a problem cleaning the scenario", err);
        }
    } else {
        info!("The scenario has been cleaned up!");
    }

    if warnings.is_empty() {
        Ok(())
    } else {
        Err(anyhow!(
            "There were warnings during scenario execution:\n{warnings}"
        ))
    }
}

pub mod scenario;


use std::{
    error::Error,
    fmt::{Debug, Display},
    time::{Duration, SystemTime},
};

use anyhow::anyhow;
use aws_config::SdkConfig;
use aws_sdk_autoscaling::{
    error::{DisplayErrorContext, ProvideErrorMetadata},
    types::{Activity, AutoScalingGroup, LaunchTemplateSpecification},
};
use aws_sdk_ec2::types::RequestLaunchTemplateData;
use tracing::trace;

const LAUNCH_TEMPLATE_NAME: &str = "SDK_Code_Examples_EC2_Autoscaling_template_from_Rust_SDK";
const AUTOSCALING_GROUP_NAME: &str = "SDK_Code_Examples_EC2_Autoscaling_Group_from_Rust_SDK";
const MAX_WAIT: Duration = Duration::from_secs(5 * 60); // Wait at most 25 seconds.
const WAIT_TIME: Duration = Duration::from_millis(500); // Wait half a second at a time.

struct Waiter {
    start: SystemTime,
    max: Duration,
}

impl Waiter {
    fn new() -> Self {
        Waiter {
            start: SystemTime::now(),
            max: MAX_WAIT,
        }
    }

    async fn sleep(&self) -> Result<(), ScenarioError> {
        if SystemTime::now()
            .duration_since(self.start)
            .unwrap_or(Duration::MAX)
            > self.max
        {
            Err(ScenarioError::with(
                "Exceeded maximum wait duration for stable group",
            ))
        } else {
            tokio::time::sleep(WAIT_TIME).await;
            Ok(())
        }
    }
}

pub struct AutoScalingScenario {
    ec2: aws_sdk_ec2::Client,
    autoscaling: aws_sdk_autoscaling::Client,
    launch_template_arn: String,
    auto_scaling_group_name: String,
}

impl Display for AutoScalingScenario {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        f.write_fmt(format_args!(
            "\tLaunch Template ID: {}\n",
            self.launch_template_arn
        ))?;
        f.write_fmt(format_args!(
            "\tScaling Group Name: {}\n",
            self.auto_scaling_group_name
        ))?;

        Ok(())
    }
}

pub struct AutoScalingScenarioDescription {
    group: Result<Vec<String>, ScenarioError>,
    instances: Result<Vec<String>, anyhow::Error>,
    activities: Result<Vec<Activity>, anyhow::Error>,
}

impl Display for AutoScalingScenarioDescription {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        writeln!(f, "\t      Group status:")?;
        match &self.group {
            Ok(groups) => {
                for status in groups {
                    writeln!(f, "\t\t- {status}")?;
                }
            }
            Err(e) => writeln!(f, "\t\t! - {e}")?,
        }
        writeln!(f, "\t         Instances:")?;
        match &self.instances {
            Ok(instances) => {
                for instance in instances {
                    writeln!(f, "\t\t- {instance}")?;
                }
            }
            Err(e) => writeln!(f, "\t\t! {e}")?,
        }

        writeln!(f, "\t        Activities:")?;
        match &self.activities {
            Ok(activities) => {
                for activity in activities {
                    writeln!(
                        f,
                        "\t\t- {} Progress: {}% Status: {:?} End: {:?}",
                        activity.cause().unwrap_or("Unknown"),
                        activity.progress.unwrap_or(-1),
                        activity.status_code(),
                        // activity.status_message().unwrap_or_default()
                        activity.end_time(),
                    )?;
                }
            }
            Err(e) => writeln!(f, "\t\t! {e}")?,
        }

        Ok(())
    }
}

#[derive(Debug)]
struct MetadataError {
    message: Option<String>,
    code: Option<String>,
}

impl MetadataError {
    fn from(err: &dyn ProvideErrorMetadata) -> Self {
        MetadataError {
            message: err.message().map(|s| s.to_string()),
            code: err.code().map(|s| s.to_string()),
        }
    }
}

impl Display for MetadataError {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        let display = match (&self.message, &self.code) {
            (None, None) => "Unknown".to_string(),
            (None, Some(code)) => format!("({code})"),
            (Some(message), None) => message.to_string(),
            (Some(message), Some(code)) => format!("{message} ({code})"),
        };
        write!(f, "{display}")
    }
}

#[derive(Debug)]
pub struct ScenarioError {
    message: String,
    context: Option<MetadataError>,
}

impl ScenarioError {
    pub fn with(message: impl Into<String>) -> Self {
        ScenarioError {
            message: message.into(),
            context: None,
        }
    }

    pub fn new(message: impl Into<String>, err: &dyn ProvideErrorMetadata) -> Self {
        ScenarioError {
            message: message.into(),
            context: Some(MetadataError::from(err)),
        }
    }
}

impl Error for ScenarioError {
    // While `Error` can capture `source` information about the underlying error, for this example
    // the ScenarioError captures the underlying information in MetadataError and treats it as a
    // single Error from this Crate. In other contexts, it may be appropriate to model the error
    // as including the SdkError as its source.
}
impl Display for ScenarioError {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        match &self.context {
            Some(c) => write!(f, "{}: {}", self.message, c),
            None => write!(f, "{}", self.message),
        }
    }
}

impl AutoScalingScenario {
    pub async fn prepare_scenario(sdk_config: &SdkConfig) -> Result<Self, Vec<ScenarioError>> {
        let ec2 = aws_sdk_ec2::Client::new(sdk_config);
        let autoscaling = aws_sdk_autoscaling::Client::new(sdk_config);

        let auto_scaling_group_name = String::from(AUTOSCALING_GROUP_NAME);

        // Before creating any resources, prepare the list of AZs
        let availablity_zones = ec2.describe_availability_zones().send().await;
        if let Err(err) = availablity_zones {
            return Err(vec![ScenarioError::new("Failed to find AZs", &err)]);
        }

        let availability_zones: Vec<String> = availablity_zones
            .unwrap()
            .availability_zones
            .unwrap_or_default()
            .iter()
            .take(3)
            .map(|z| z.zone_name.clone().unwrap())
            .collect();

        // 1. Create an EC2 launch template that you'll use to create an auto scaling group. Bonus: use SDK with EC2.CreateLaunchTemplate to create the launch template.
        //   * Recommended: InstanceType='t1.micro', ImageId='ami-0ca285d4c2cda3300'
        let create_launch_template = ec2
            .create_launch_template()
            .launch_template_name(LAUNCH_TEMPLATE_NAME)
            .launch_template_data(
                RequestLaunchTemplateData::builder()
                    .instance_type(aws_sdk_ec2::types::InstanceType::T1Micro)
                    .image_id("ami-0ca285d4c2cda3300")
                    .build(),
            )
            .send()
            .await
            .map_err(|err| vec![ScenarioError::new("Failed to create launch template", &err)])?;

        let launch_template_arn = match create_launch_template.launch_template {
            Some(launch_template) => launch_template.launch_template_id.unwrap_or_default(),
            None => {
                // Try to delete the launch template
                let _ = ec2
                    .delete_launch_template()
                    .launch_template_name(LAUNCH_TEMPLATE_NAME)
                    .send()
                    .await;
                return Err(vec![ScenarioError::with("Failed to load launch template")]);
            }
        };

        // 2. CreateAutoScalingGroup: pass it the launch template you created in step 0. Give it min/max of 1 instance.
        //   You can use EC2.describe_availability_zones() to get a list of AZs (you have to specify an AZ when you create the group).
        //   Wait for instance to launch. Use a waiter if you have one, otherwise DescribeAutoScalingInstances until LifecycleState='InService'
        if let Err(err) = autoscaling
            .create_auto_scaling_group()
            .auto_scaling_group_name(auto_scaling_group_name.as_str())
            .launch_template(
                LaunchTemplateSpecification::builder()
                    .launch_template_id(launch_template_arn.clone())
                    .version("$Latest")
                    .build(),
            )
            .max_size(1)
            .min_size(1)
            .set_availability_zones(Some(availability_zones))
            .send()
            .await
        {
            let mut errs = vec![ScenarioError::new(
                "Failed to create autoscaling group",
                &err,
            )];

            if let Err(err) = autoscaling
                .delete_auto_scaling_group()
                .auto_scaling_group_name(auto_scaling_group_name.as_str())
                .send()
                .await
            {
                errs.push(ScenarioError::new(
                    "Failed to clean up autoscaling group",
                    &err,
                ));
            }

            if let Err(err) = ec2
                .delete_launch_template()
                .launch_template_id(launch_template_arn.clone())
                .send()
                .await
            {
                errs.push(ScenarioError::new(
                    "Failed to clean up launch template",
                    &err,
                ));
            }
            return Err(errs);
        }

        let scenario = AutoScalingScenario {
            ec2,
            autoscaling: autoscaling.clone(), // Clients are cheap so cloning here to prevent a move is ok.
            auto_scaling_group_name: auto_scaling_group_name.clone(),
            launch_template_arn,
        };

        let enable_metrics_collection = autoscaling
            .enable_metrics_collection()
            .auto_scaling_group_name(auto_scaling_group_name.as_str())
            .granularity("1Minute")
            .set_metrics(Some(vec![
                String::from("GroupMinSize"),
                String::from("GroupMaxSize"),
                String::from("GroupDesiredCapacity"),
                String::from("GroupInServiceInstances"),
                String::from("GroupTotalInstances"),
            ]))
            .send()
            .await;

        match enable_metrics_collection {
            Ok(_) => Ok(scenario),
            Err(err) => {
                scenario.clean_scenario().await?;
                Err(vec![ScenarioError::new(
                    "Failed to enable metrics collections for group",
                    &err,
                )])
            }
        }
    }

    pub async fn clean_scenario(self) -> Result<(), Vec<ScenarioError>> {
        let _ = self.wait_for_no_scaling().await;
        let delete_group = self
            .autoscaling
            .delete_auto_scaling_group()
            .auto_scaling_group_name(self.auto_scaling_group_name.clone())
            .send()
            .await;

        // 14. Delete LaunchTemplate.
        let delete_launch_template = self
            .ec2
            .delete_launch_template()
            .launch_template_id(self.launch_template_arn.clone())
            .send()
            .await;

        let early_exit = match (delete_group, delete_launch_template) {
            (Ok(_), Ok(_)) => Ok(()),
            (Ok(_), Err(e)) => Err(vec![ScenarioError::new(
                "There was an error cleaning the launch template",
                &e,
            )]),
            (Err(e), Ok(_)) => Err(vec![ScenarioError::new(
                "There was an error cleaning the scale group",
                &e,
            )]),
            (Err(e1), Err(e2)) => Err(vec![
                ScenarioError::new("Multiple error cleaning the scenario Scale Group", &e1),
                ScenarioError::new("Multiple error cleaning the scenario Launch Template", &e2),
            ]),
        };

        if early_exit.is_err() {
            early_exit
        } else {
            // Wait for delete_group to finish
            let waiter = Waiter::new();
            let mut errors = Vec::<ScenarioError>::new();
            while errors.len() < 3 {
                if let Err(e) = waiter.sleep().await {
                    errors.push(e);
                    continue;
                }
                let describe_group = self
                    .autoscaling
                    .describe_auto_scaling_groups()
                    .auto_scaling_group_names(self.auto_scaling_group_name.clone())
                    .send()
                    .await;
                match describe_group {
                    Ok(group) => match group.auto_scaling_groups().first() {
                        Some(group) => {
                            if group.status() != Some("Delete in progress") {
                                errors.push(ScenarioError::with(format!(
                                    "Group in an unknown state while deleting: {}",
                                    group.status().unwrap_or("unknown error")
                                )));
                                return Err(errors);
                            }
                        }
                        None => return Ok(()),
                    },
                    Err(err) => {
                        errors.push(ScenarioError::new("Failed to describe autoscaling group during cleanup 3 times, last error", &err));
                    }
                }
                if errors.len() > 3 {
                    return Err(errors);
                }
            }
            Err(vec![ScenarioError::with(
                "Exited cleanup wait loop without retuning success or failing after three rounds",
            )])
        }
    }

    pub async fn describe_scenario(&self) -> AutoScalingScenarioDescription {
        let group = self
            .autoscaling
            .describe_auto_scaling_groups()
            .auto_scaling_group_names(self.auto_scaling_group_name.clone())
            .send()
            .await
            .map(|s| {
                s.auto_scaling_groups()
                    .iter()
                    .map(|s| {
                        format!(
                            "{}: {}",
                            s.auto_scaling_group_name().unwrap_or("Unknown"),
                            s.status().unwrap_or("Unknown")
                        )
                    })
                    .collect::<Vec<String>>()
            })
            .map_err(|e| {
                ScenarioError::new("Failed to describe auto scaling groups for scenario", &e)
            });

        let instances = self
            .list_instances()
            .await
            .map_err(|e| anyhow!("There was an error listing instances: {e}",));

        // 10. DescribeScalingActivities: list the scaling activities that have occurred for the group so far.
        //   Bonus: use CloudWatch API to get and show some metrics collected for the group.
        //   CW.ListMetrics with Namespace='AWS/AutoScaling' and Dimensions=[{'Name': 'AutoScalingGroupName', 'Value': }]
        //   CW.GetMetricStatistics with Statistics='Sum'. Start and End times must be in UTC!
        let activities = self
            .autoscaling
            .describe_scaling_activities()
            .auto_scaling_group_name(self.auto_scaling_group_name.clone())
            .into_paginator()
            .items()
            .send()
            .collect::<Result<Vec<_>, _>>()
            .await
            .map_err(|e| {
                anyhow!(
                    "There was an error retrieving scaling activities: {}",
                    DisplayErrorContext(&e)
                )
            });

        AutoScalingScenarioDescription {
            group,
            instances,
            activities,
        }
    }

    async fn get_group(&self) -> Result<AutoScalingGroup, ScenarioError> {
        let describe_auto_scaling_groups = self
            .autoscaling
            .describe_auto_scaling_groups()
            .auto_scaling_group_names(self.auto_scaling_group_name.clone())
            .send()
            .await;

        if let Err(err) = describe_auto_scaling_groups {
            return Err(ScenarioError::new(
                format!(
                    "Failed to get status of autoscaling group {}",
                    self.auto_scaling_group_name.clone()
                )
                .as_str(),
                &err,
            ));
        }

        let describe_auto_scaling_groups_output = describe_auto_scaling_groups.unwrap();
        let auto_scaling_groups = describe_auto_scaling_groups_output.auto_scaling_groups();
        let auto_scaling_group = auto_scaling_groups.first();

        if auto_scaling_group.is_none() {
            return Err(ScenarioError::with(format!(
                "Could not find autoscaling group {}",
                self.auto_scaling_group_name.clone()
            )));
        }

        Ok(auto_scaling_group.unwrap().clone())
    }

    pub async fn wait_for_no_scaling(&self) -> Result<(), ScenarioError> {
        let waiter = Waiter::new();
        let mut scaling = true;
        while scaling {
            waiter.sleep().await?;
            let describe_activities = self
                .autoscaling
                .describe_scaling_activities()
                .auto_scaling_group_name(self.auto_scaling_group_name.clone())
                .send()
                .await
                .map_err(|e| {
                    ScenarioError::new("Failed to get autoscaling activities for group", &e)
                })?;
            let activities = describe_activities.activities();
            trace!(
                "Waiting for no scaling found {} activities",
                activities.len()
            );
            scaling = activities.iter().any(|a| a.progress() < Some(100));
        }
        Ok(())
    }

    pub async fn wait_for_stable(&self, size: usize) -> Result<(), ScenarioError> {
        self.wait_for_no_scaling().await?;

        let mut group = self.get_group().await?;
        let mut count = count_group_instances(&group);

        let waiter = Waiter::new();
        while count != size {
            trace!("Waiting for stable {size} (current: {count})");
            waiter.sleep().await?;
            group = self.get_group().await?;
            count = count_group_instances(&group);
        }

        Ok(())
    }

    pub async fn list_instances(&self) -> Result<Vec<String>, ScenarioError> {
        // The direct way to list instances is by using DescribeAutoScalingGroup's instances property. However, this returns a Vec<Instance>, as opposed to a Vec<AutoScalingInstanceDetails>.
        // Ok(self.get_group().await?.instances.unwrap_or_default().map(|i| i.instance_id.clone().unwrap_or_default()).filter(|id| !id.is_empty()).collect())

        // Alternatively, and for the sake of example, DescribeAutoScalingInstances returns a list that can be filtered by the client.
        self.autoscaling
            .describe_auto_scaling_instances()
            .into_paginator()
            .items()
            .send()
            .try_collect()
            .await
            .map(|items| {
                items
                    .into_iter()
                    .filter(|i| {
                        i.auto_scaling_group_name.as_deref()
                            == Some(self.auto_scaling_group_name.as_str())
                    })
                    .map(|i| i.instance_id.unwrap_or_default())
                    .filter(|id| !id.is_empty())
                    .collect::<Vec<String>>()
            })
            .map_err(|err| ScenarioError::new("Failed to get list of auto scaling instances", &err))
    }

    pub async fn scale_min_size(&self, size: i32) -> Result<(), ScenarioError> {
        let update_group = self
            .autoscaling
            .update_auto_scaling_group()
            .auto_scaling_group_name(self.auto_scaling_group_name.clone())
            .min_size(size)
            .send()
            .await;
        if let Err(err) = update_group {
            return Err(ScenarioError::new(
                format!("Failer to update group to min size ({size}))").as_str(),
                &err,
            ));
        }
        Ok(())
    }

    pub async fn scale_max_size(&self, size: i32) -> Result<(), ScenarioError> {
        // 5. UpdateAutoScalingGroup: update max size to 3.
        let update_group = self
            .autoscaling
            .update_auto_scaling_group()
            .auto_scaling_group_name(self.auto_scaling_group_name.clone())
            .max_size(size)
            .send()
            .await;
        if let Err(err) = update_group {
            return Err(ScenarioError::new(
                format!("Failed to update group to max size ({size})").as_str(),
                &err,
            ));
        }
        Ok(())
    }

    pub async fn scale_desired_capacity(&self, capacity: i32) -> Result<(), ScenarioError> {
        // 7. SetDesiredCapacity: set desired capacity to 2.
        //   Wait for a second instance to launch.
        let update_group = self
            .autoscaling
            .set_desired_capacity()
            .auto_scaling_group_name(self.auto_scaling_group_name.clone())
            .desired_capacity(capacity)
            .send()
            .await;
        if let Err(err) = update_group {
            return Err(ScenarioError::new(
                format!("Failed to update group to desired capacity ({capacity}))").as_str(),
                &err,
            ));
        }
        Ok(())
    }

    pub async fn scale_group_to_zero(&self) -> Result<(), ScenarioError> {
        // If this fails it's fine, just means there are extra cloudwatch metrics events for the scale-down.
        let _ = self
            .autoscaling
            .disable_metrics_collection()
            .auto_scaling_group_name(self.auto_scaling_group_name.clone())
            .send()
            .await;

        // 12. DeleteAutoScalingGroup (to delete the group you must stop all instances):
        //   UpdateAutoScalingGroup with MinSize=0
        let update_group = self
            .autoscaling
            .update_auto_scaling_group()
            .auto_scaling_group_name(self.auto_scaling_group_name.clone())
            .min_size(0)
            .desired_capacity(0)
            .send()
            .await;
        if let Err(err) = update_group {
            return Err(ScenarioError::new(
                "Failed to update group for scaling down&",
                &err,
            ));
        }

        let stable = self.wait_for_stable(0).await;
        if let Err(err) = stable {
            return Err(ScenarioError::with(format!(
                "Error while waiting for group to be stable on scale down: {err}"
            )));
        }

        Ok(())
    }

    pub async fn terminate_some_instance(&self) -> Result<(), ScenarioError> {
        // Retrieve a list of instances in the auto scaling group.
        let auto_scaling_group = self.get_group().await?;
        let instances = auto_scaling_group.instances();
        // Or use other logic to find an instance to terminate.
        let instance = instances.first();
        if let Some(instance) = instance {
            let instance_id = if let Some(instance_id) = instance.instance_id() {
                instance_id
            } else {
                return Err(ScenarioError::with("Missing instance id"));
            };
            let termination = self
                .ec2
                .terminate_instances()
                .instance_ids(instance_id)
                .send()
                .await;
            if let Err(err) = termination {
                Err(ScenarioError::new(
                    "There was a problem terminating an instance",
                    &err,
                ))
            } else {
                Ok(())
            }
        } else {
            Err(ScenarioError::with("There was no instance to terminate"))
        }
    }
}

fn count_group_instances(group: &AutoScalingGroup) -> usize {
    group.instances.as_ref().map(|i| i.len()).unwrap_or(0)
}