CloudWatch Metrics

MicroStack emulates Amazon CloudWatch Metrics, supporting custom metric ingestion, metric queries, standard and composite alarms, dashboards, and alarm state transitions. Both the classic Query/XML protocol and the Smithy RPC v2 CBOR protocol are accepted, so all AWS SDK versions work without configuration changes.

Supported Operations

PutMetricData, GetMetricStatistics, GetMetricData, ListMetrics, PutMetricAlarm, PutCompositeAlarm, DescribeAlarms, DescribeAlarmsForMetric, DescribeAlarmHistory, DeleteAlarms, EnableAlarmActions, DisableAlarmActions, SetAlarmState, TagResource, UntagResource, ListTagsForResource, PutDashboard, GetDashboard, DeleteDashboards, ListDashboards

Usage

var client = new AmazonCloudWatchClient(
    new BasicAWSCredentials("test", "test"),
    new AmazonCloudWatchConfig
    {
        RegionEndpoint = RegionEndpoint.USEast1,
        ServiceURL = "http://localhost:4566",
    });

// Publish custom metrics
await client.PutMetricDataAsync(new PutMetricDataRequest
{
    Namespace = "MyApp",
    MetricData =
    [
        new MetricDatum
        {
            MetricName = "RequestCount",
            Value = 42.0,
            Unit = StandardUnit.Count,
            Dimensions = [new Dimension { Name = "API", Value = "/users" }],
        },
        new MetricDatum
        {
            MetricName = "Latency",
            Value = 123.5,
            Unit = StandardUnit.Milliseconds,
        },
    ],
});

// List metrics in a namespace
var listResp = await client.ListMetricsAsync(new ListMetricsRequest
{
    Namespace = "MyApp",
});
Console.WriteLine(listResp.Metrics.Count); // 2

// Query metric statistics
var now = DateTimeOffset.UtcNow;
var statsResp = await client.GetMetricStatisticsAsync(new GetMetricStatisticsRequest
{
    Namespace = "MyApp",
    MetricName = "Latency",
    Period = 60,
    StartTime = now.AddMinutes(-10).UtcDateTime,
    EndTime   = now.AddMinutes(10).UtcDateTime,
    Statistics = [Statistic.Average, Statistic.Sum, Statistic.Maximum],
});
Console.WriteLine(statsResp.Datapoints[0].Average); // 123.5

Alarms

// Create a metric alarm
await client.PutMetricAlarmAsync(new PutMetricAlarmRequest
{
    AlarmName = "high-latency",
    MetricName = "Latency",
    Namespace = "MyApp",
    Statistic = Statistic.Average,
    Period = 60,
    EvaluationPeriods = 1,
    Threshold = 500.0,
    ComparisonOperator = ComparisonOperator.GreaterThanThreshold,
    AlarmActions = ["arn:aws:sns:us-east-1:000000000000:my-alarm-topic"],
    AlarmDescription = "Alert when p50 latency exceeds 500ms",
});

// Describe alarms
var alarms = await client.DescribeAlarmsAsync(new DescribeAlarmsRequest
{
    AlarmNames = ["high-latency"],
});
Console.WriteLine(alarms.MetricAlarms[0].StateValue); // INSUFFICIENT_DATA

// Manually set alarm state (useful in tests)
await client.SetAlarmStateAsync(new SetAlarmStateRequest
{
    AlarmName = "high-latency",
    StateValue = StateValue.ALARM,
    StateReason = "Simulated alarm for test",
});

// Create a composite alarm
await client.PutCompositeAlarmAsync(new PutCompositeAlarmRequest
{
    AlarmName = "composite-alarm",
    AlarmRule = "ALARM(high-latency)",
    AlarmDescription = "Composite alarm for high latency",
});