Use GetMetricStatistics with an AWS SDK or CLI

    /// <summary>
    /// Get billing statistics using a call to a wrapper class.
    /// </summary>
    /// <returns>A collection of billing statistics.</returns>
    private static async Task<List<Datapoint>> SetupBillingStatistics()
    {
        // Make a request for EstimatedCharges with a period of one day for the past seven days.
        var billingStatistics = await _cloudWatchWrapper.GetMetricStatistics(
            "AWS/Billing",
            "EstimatedCharges",
            new List<string>() { "Maximum" },
            new List<Dimension>() { new Dimension { Name = "Currency", Value = "USD" } },
            7,
            86400);

        billingStatistics = billingStatistics.OrderBy(n => n.Timestamp).ToList();

        return billingStatistics;
    }

    /// <summary>
    /// Wrapper to get statistics for a specific CloudWatch metric.
    /// </summary>
    /// <param name="metricNamespace">The namespace of the metric.</param>
    /// <param name="metricName">The name of the metric.</param>
    /// <param name="statistics">The list of statistics to include.</param>
    /// <param name="dimensions">The list of dimensions to include.</param>
    /// <param name="days">The number of days in the past to include.</param>
    /// <param name="period">The period for the data.</param>
    /// <returns>A list of DataPoint objects for the statistics.</returns>
    public async Task<List<Datapoint>> GetMetricStatistics(string metricNamespace,
        string metricName, List<string> statistics, List<Dimension> dimensions, int days, int period)
    {
        var metricStatistics = await _amazonCloudWatch.GetMetricStatisticsAsync(
            new GetMetricStatisticsRequest()
            {
                Namespace = metricNamespace,
                MetricName = metricName,
                Dimensions = dimensions,
                Statistics = statistics,
                StartTimeUtc = DateTime.UtcNow.AddDays(-days),
                EndTimeUtc = DateTime.UtcNow,
                Period = period
            });

        return metricStatistics.Datapoints;
    }

To get the CPU utilization per EC2 instance

The following example uses the get-metric-statistics command to get the CPU utilization for an EC2 instance with the ID i-abcdef.

aws cloudwatch get-metric-statistics --metric-name CPUUtilization --start-time 2014-04-08T23:18:00Z --end-time 2014-04-09T23:18:00Z --period 3600 --namespace AWS/EC2 --statistics Maximum --dimensions Name=InstanceId,Value=i-abcdef

Output:

{
    "Datapoints": [
        {
            "Timestamp": "2014-04-09T11:18:00Z",
            "Maximum": 44.79,
            "Unit": "Percent"
        },
        {
            "Timestamp": "2014-04-09T20:18:00Z",
            "Maximum": 47.92,
            "Unit": "Percent"
        },
        {
            "Timestamp": "2014-04-09T19:18:00Z",
            "Maximum": 50.85,
            "Unit": "Percent"
        },
        {
            "Timestamp": "2014-04-09T09:18:00Z",
            "Maximum": 47.92,
            "Unit": "Percent"
        },
        {
            "Timestamp": "2014-04-09T03:18:00Z",
            "Maximum": 76.84,
            "Unit": "Percent"
        },
        {
            "Timestamp": "2014-04-09T21:18:00Z",
            "Maximum": 48.96,
            "Unit": "Percent"
        },
        {
            "Timestamp": "2014-04-09T14:18:00Z",
            "Maximum": 47.92,
            "Unit": "Percent"
        },
        {
            "Timestamp": "2014-04-09T08:18:00Z",
            "Maximum": 47.92,
            "Unit": "Percent"
        },
        {
            "Timestamp": "2014-04-09T16:18:00Z",
            "Maximum": 45.55,
            "Unit": "Percent"
        },
        {
            "Timestamp": "2014-04-09T06:18:00Z",
            "Maximum": 47.92,
            "Unit": "Percent"
        },
        {
            "Timestamp": "2014-04-09T13:18:00Z",
            "Maximum": 45.08,
            "Unit": "Percent"
        },
        {
            "Timestamp": "2014-04-09T05:18:00Z",
            "Maximum": 47.92,
            "Unit": "Percent"
        },
        {
            "Timestamp": "2014-04-09T18:18:00Z",
            "Maximum": 46.88,
            "Unit": "Percent"
        },
        {
            "Timestamp": "2014-04-09T17:18:00Z",
            "Maximum": 52.08,
            "Unit": "Percent"
        },
        {
            "Timestamp": "2014-04-09T07:18:00Z",
            "Maximum": 47.92,
            "Unit": "Percent"
        },
        {
            "Timestamp": "2014-04-09T02:18:00Z",
            "Maximum": 51.23,
            "Unit": "Percent"
        },
        {
            "Timestamp": "2014-04-09T12:18:00Z",
            "Maximum": 47.67,
            "Unit": "Percent"
        },
        {
            "Timestamp": "2014-04-08T23:18:00Z",
            "Maximum": 46.88,
            "Unit": "Percent"
        },
        {
            "Timestamp": "2014-04-09T10:18:00Z",
            "Maximum": 51.91,
            "Unit": "Percent"
        },
        {
            "Timestamp": "2014-04-09T04:18:00Z",
            "Maximum": 47.13,
            "Unit": "Percent"
        },
        {
            "Timestamp": "2014-04-09T15:18:00Z",
            "Maximum": 48.96,
            "Unit": "Percent"
        },
        {
            "Timestamp": "2014-04-09T00:18:00Z",
            "Maximum": 48.16,
            "Unit": "Percent"
        },
        {
            "Timestamp": "2014-04-09T01:18:00Z",
            "Maximum": 49.18,
            "Unit": "Percent"
        }
    ],
    "Label": "CPUUtilization"
}

Specifying multiple dimensions

The following example illustrates how to specify multiple dimensions. Each dimension is specified as a Name/Value pair, with a comma between the name and the value. Multiple dimensions are separated by a space. If a single metric includes multiple dimensions, you must specify a value for every defined dimension.

For more examples using the get-metric-statistics command, see Get Statistics for a Metric in the Amazon CloudWatch Developer Guide.

aws cloudwatch get-metric-statistics --metric-name Buffers --namespace MyNameSpace --dimensions Name=InstanceID,Value=i-abcdef Name=InstanceType,Value=m1.small --start-time 2016-10-15T04:00:00Z --end-time 2016-10-19T07:00:00Z --statistics Average --period 60

    /**
     * Retrieves and displays metric statistics for the specified parameters.
     *
     * @param nameSpace    the namespace for the metric
     * @param metVal       the name of the metric
     * @param metricOption the statistic to retrieve for the metric (e.g., "Maximum", "Average")
     * @param date         the date for which to retrieve the metric statistics, in the format "yyyy-MM-dd'T'HH:mm:ss'Z'"
     * @param myDimension  the dimension(s) to filter the metric statistics by
     * @return a {@link CompletableFuture} that completes when the metric statistics have been retrieved and displayed
     */
    public CompletableFuture<GetMetricStatisticsResponse> getAndDisplayMetricStatisticsAsync(String nameSpace, String metVal,
                                                                                             String metricOption, String date, Dimension myDimension) {

        Instant start = Instant.parse(date);
        Instant endDate = Instant.now();

        // Building the request for metric statistics.
        GetMetricStatisticsRequest statisticsRequest = GetMetricStatisticsRequest.builder()
            .endTime(endDate)
            .startTime(start)
            .dimensions(myDimension)
            .metricName(metVal)
            .namespace(nameSpace)
            .period(86400) // 1 day period
            .statistics(Statistic.fromValue(metricOption))
            .build();

        return getAsyncClient().getMetricStatistics(statisticsRequest)
            .whenComplete((response, exception) -> {
                if (response != null) {
                    List<Datapoint> data = response.datapoints();
                    if (!data.isEmpty()) {
                        for (Datapoint datapoint : data) {
                            logger.info("Timestamp: {} Maximum value: {}", datapoint.timestamp(), datapoint.maximum());
                        }
                    } else {
                        logger.info("The returned data list is empty");
                    }
                } else {
                    logger.info("Failed to get metric statistics: {} ", exception.getMessage());
                }
            })
            .exceptionally(exception -> {
                throw new RuntimeException("Error while getting metric statistics: " + exception.getMessage(), exception);
            });
    }

suspend fun getAndDisplayMetricStatistics(
    nameSpaceVal: String,
    metVal: String,
    metricOption: String,
    date: String,
    myDimension: Dimension,
) {
    val start = Instant.parse(date)
    val endDate = Instant.now()
    val statisticsRequest =
        GetMetricStatisticsRequest {
            endTime =
                aws.smithy.kotlin.runtime.time
                    .Instant(endDate)
            startTime =
                aws.smithy.kotlin.runtime.time
                    .Instant(start)
            dimensions = listOf(myDimension)
            metricName = metVal
            namespace = nameSpaceVal
            period = 86400
            statistics = listOf(Statistic.fromValue(metricOption))
        }

    CloudWatchClient { region = "us-east-1" }.use { cwClient ->
        val response = cwClient.getMetricStatistics(statisticsRequest)
        val data = response.datapoints
        if (data != null) {
            if (data.isNotEmpty()) {
                for (datapoint in data) {
                    println("Timestamp: ${datapoint.timestamp} Maximum value: ${datapoint.maximum}")
                }
            } else {
                println("The returned data list is empty")
            }
        }
    }
}

class CloudWatchWrapper:
    """Encapsulates Amazon CloudWatch functions."""

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


    def get_metric_statistics(self, namespace, name, start, end, period, stat_types):
        """
        Gets statistics for a metric within a specified time span. Metrics are grouped
        into the specified period.

        :param namespace: The namespace of the metric.
        :param name: The name of the metric.
        :param start: The UTC start time of the time span to retrieve.
        :param end: The UTC end time of the time span to retrieve.
        :param period: The period, in seconds, in which to group metrics. The period
                       must match the granularity of the metric, which depends on
                       the metric's age. For example, metrics that are older than
                       three hours have a one-minute granularity, so the period must
                       be at least 60 and must be a multiple of 60.
        :param stat_types: The type of statistics to retrieve, such as average value
                           or maximum value.
        :return: The retrieved statistics for the metric.
        """
        try:
            metric = self.cloudwatch_resource.Metric(namespace, name)
            stats = metric.get_statistics(
                StartTime=start, EndTime=end, Period=period, Statistics=stat_types
            )
            logger.info(
                "Got %s statistics for %s.", len(stats["Datapoints"]), stats["Label"]
            )
        except ClientError:
            logger.exception("Couldn't get statistics for %s.%s.", namespace, name)
            raise
        else:
            return stats