MetricFilter

The MetricFilter resource lets you create and manage AWS Logs MetricFilters for monitoring and analyzing log data. Metric filters allow you to extract metric data from logs for use in CloudWatch.

Minimal Example

Create a simple metric filter that counts the number of error messages in a log group.

import AWS from "alchemy/aws/control";

const errorMetricFilter = await AWS.Logs.MetricFilter("ErrorMetricFilter", {
  MetricTransformations: [{
    MetricValue: "1",
    MetricNamespace: "MyApp",
    MetricName: "ErrorCount"
  }],
  FilterPattern: "{ $.level = \"ERROR\" }",
  LogGroupName: "MyAppLogGroup",
  ApplyOnTransformedLogs: true,
  FilterName: "ErrorFilter"
});

Advanced Configuration

This example shows how to configure a metric filter with multiple transformations and a custom filter name.

const detailedMetricFilter = await AWS.Logs.MetricFilter("DetailedMetricFilter", {
  MetricTransformations: [{
    MetricValue: "1",
    MetricNamespace: "MyApp",
    MetricName: "ErrorCount"
  }, {
    MetricValue: "1",
    MetricNamespace: "MyApp",
    MetricName: "WarningCount"
  }],
  FilterPattern: "{ $.level = \"ERROR\" || $.level = \"WARNING\" }",
  LogGroupName: "MyAppLogGroup",
  FilterName: "DetailedFilter"
});

Using Existing Log Groups

This example demonstrates how to create a metric filter for an existing log group without failing if it already exists.

const existingLogGroupMetricFilter = await AWS.Logs.MetricFilter("ExistingLogGroupMetricFilter", {
  MetricTransformations: [{
    MetricValue: "1",
    MetricNamespace: "MyApp",
    MetricName: "CriticalErrors"
  }],
  FilterPattern: "{ $.level = \"CRITICAL\" }",
  LogGroupName: "ExistingLogGroup",
  adopt: true // This will adopt the existing resource if it already exists
});

Applying on Transformed Logs

In this example, we create a metric filter that applies to transformed logs, allowing you to get metrics from processed data.

const transformedLogsMetricFilter = await AWS.Logs.MetricFilter("TransformedLogsMetricFilter", {
  MetricTransformations: [{
    MetricValue: "1",
    MetricNamespace: "MyApp",
    MetricName: "TransformedLogCount"
  }],
  FilterPattern: "{ $.statusCode = 200 }",
  LogGroupName: "TransformedLogsGroup",
  ApplyOnTransformedLogs: true
});