# Working with CloudWatch Alarms
<a name="examples-cloudwatch-create-alarms"></a>

## Prerequisites
<a name="codeExamplePrereq"></a>

Before you begin, we recommend you read [Getting started using the AWS SDK for C\$1\$1](getting-started.md). 

Download the example code and build the solution as described in [Getting started on code examples](getting-started-code-examples.md). 

To run the examples, the user profile your code uses to make the requests must have proper permissions in AWS (for the service and the action). For more information, see [Providing AWS credentials](credentials.md).

## Create an Alarm
<a name="create-an-alarm"></a>

To create an alarm based on a CloudWatch metric, call the CloudWatchClient’s `PutMetricAlarm` function with a [PutMetricAlarmRequest](https://docs.aws.amazon.com/sdk-for-cpp/latest/api/aws-cpp-sdk-monitoring/html/class_aws_1_1_cloud_watch_1_1_model_1_1_put_metric_alarm_request.html) filled with the alarm conditions.

 **Includes** 

```
#include <aws/core/Aws.h>
#include <aws/monitoring/CloudWatchClient.h>
#include <aws/monitoring/model/PutMetricAlarmRequest.h>
#include <iostream>
```

 **Code** 

```
        Aws::CloudWatch::CloudWatchClient cw;
        Aws::CloudWatch::Model::PutMetricAlarmRequest request;
        request.SetAlarmName(alarm_name);
        request.SetComparisonOperator(
            Aws::CloudWatch::Model::ComparisonOperator::GreaterThanThreshold);
        request.SetEvaluationPeriods(1);
        request.SetMetricName("CPUUtilization");
        request.SetNamespace("AWS/EC2");
        request.SetPeriod(60);
        request.SetStatistic(Aws::CloudWatch::Model::Statistic::Average);
        request.SetThreshold(70.0);
        request.SetActionsEnabled(false);
        request.SetAlarmDescription("Alarm when server CPU exceeds 70%");
        request.SetUnit(Aws::CloudWatch::Model::StandardUnit::Seconds);

        Aws::CloudWatch::Model::Dimension dimension;
        dimension.SetName("InstanceId");
        dimension.SetValue(instanceId);

        request.AddDimensions(dimension);

        auto outcome = cw.PutMetricAlarm(request);
        if (!outcome.IsSuccess())
        {
            std::cout << "Failed to create CloudWatch alarm:" <<
                outcome.GetError().GetMessage() << std::endl;
        }
        else
        {
            std::cout << "Successfully created CloudWatch alarm " << alarm_name
                << std::endl;
        }
```

See the [complete example](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/cpp/example_code/cloudwatch/put_metric_alarm.cpp).

## List Alarms
<a name="list-alarms"></a>

To list the CloudWatch alarms that you have created, call the CloudWatchClient’s `DescribeAlarms` function with a [DescribeAlarmsRequest](https://docs.aws.amazon.com/sdk-for-cpp/latest/api/aws-cpp-sdk-monitoring/html/class_aws_1_1_cloud_watch_1_1_model_1_1_describe_alarms_request.html) that you can use to set options for the result.

 **Includes** 

```
#include <aws/core/Aws.h>
#include <aws/monitoring/CloudWatchClient.h>
#include <aws/monitoring/model/DescribeAlarmsRequest.h>
#include <aws/monitoring/model/DescribeAlarmsResult.h>
#include <iomanip>
#include <iostream>
```

 **Code** 

```
        Aws::CloudWatch::CloudWatchClient cw;
        Aws::CloudWatch::Model::DescribeAlarmsRequest request;
        request.SetMaxRecords(1);

        bool done = false;
        bool header = false;
        while (!done)
        {
            auto outcome = cw.DescribeAlarms(request);
            if (!outcome.IsSuccess())
            {
                std::cout << "Failed to describe CloudWatch alarms:" <<
                    outcome.GetError().GetMessage() << std::endl;
                break;
            }

            if (!header)
            {
                std::cout << std::left <<
                    std::setw(32) << "Name" <<
                    std::setw(64) << "Arn" <<
                    std::setw(64) << "Description" <<
                    std::setw(20) << "LastUpdated" <<
                    std::endl;
                header = true;
            }

            const auto &alarms = outcome.GetResult().GetMetricAlarms();
            for (const auto &alarm : alarms)
            {
                std::cout << std::left <<
                    std::setw(32) << alarm.GetAlarmName() <<
                    std::setw(64) << alarm.GetAlarmArn() <<
                    std::setw(64) << alarm.GetAlarmDescription() <<
                    std::setw(20) <<
                    alarm.GetAlarmConfigurationUpdatedTimestamp().ToGmtString(
                        SIMPLE_DATE_FORMAT_STR) <<
                    std::endl;
            }

            const auto &next_token = outcome.GetResult().GetNextToken();
            request.SetNextToken(next_token);
            done = next_token.empty();
        }
```

The list of alarms can be obtained by calling `getMetricAlarms` on the [DescribeAlarmsResult](https://docs.aws.amazon.com/sdk-for-cpp/latest/api/aws-cpp-sdk-monitoring/html/class_aws_1_1_cloud_watch_1_1_model_1_1_describe_alarms_result.html) that is returned by `DescribeAlarms`.

The results may be *paged*. To retrieve the next batch of results, call `SetNextToken` on the original request object with the return value of the `DescribeAlarmsResult` object’s `GetNextToken` function, and pass the modified request object back to another call to `DescribeAlarms`.

**Note**  
You can also retrieve alarms for a specific metric by using the CloudWatchClient’s `DescribeAlarmsForMetric` function. Its use is similar to `DescribeAlarms`.

See the [complete example](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/cpp/example_code/cloudwatch/describe_alarms.cpp).

## Delete Alarms
<a name="delete-alarms"></a>

To delete CloudWatch alarms, call the CloudWatchClient’s `DeleteAlarms` function with a [DeleteAlarmsRequest](https://docs.aws.amazon.com/sdk-for-cpp/latest/api/aws-cpp-sdk-monitoring/html/class_aws_1_1_cloud_watch_1_1_model_1_1_delete_alarms_request.html) containing one or more names of alarms that you want to delete.

 **Includes** 

```
#include <aws/core/Aws.h>
#include <aws/monitoring/CloudWatchClient.h>
#include <aws/monitoring/model/DeleteAlarmsRequest.h>
#include <iostream>
```

 **Code** 

```
        Aws::CloudWatch::CloudWatchClient cw;
        Aws::CloudWatch::Model::DeleteAlarmsRequest request;
        request.AddAlarmNames(alarm_name);

        auto outcome = cw.DeleteAlarms(request);
        if (!outcome.IsSuccess())
        {
            std::cout << "Failed to delete CloudWatch alarm:" <<
                outcome.GetError().GetMessage() << std::endl;
        }
        else
        {
            std::cout << "Successfully deleted CloudWatch alarm " << alarm_name
                << std::endl;
        }
```

See the [complete example](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/cpp/example_code/cloudwatch/delete_alarm.cpp).

## More Information
<a name="more-information"></a>
+  [Creating Amazon CloudWatch Alarms](https://docs.aws.amazon.com/AmazonCloudWatch/latest/monitoring/AlarmThatSendsEmail.html) in the Amazon CloudWatch User Guide
+  [PutMetricAlarm](https://docs.aws.amazon.com/AmazonCloudWatch/latest/APIReference/PutMetricAlarm.html) in the Amazon CloudWatch API Reference
+  [DescribeAlarms](https://docs.aws.amazon.com/AmazonCloudWatch/latest/APIReference/DescribeAlarms.html) in the Amazon CloudWatch API Reference
+  [DeleteAlarms](https://docs.aws.amazon.com/AmazonCloudWatch/latest/APIReference/DeleteAlarms.html) in the Amazon CloudWatch API Reference