Creating an AWS CloudWatch Log Metric Filter

In this guide, we’ll walk through the process of creating an AWS CloudWatch Log Metric Filter. CloudWatch Log Metric Filters allow you to extract metric data from log events, which is useful for monitoring specific patterns or anomalies in your logs.

Steps Overview

1. Create a CloudWatch Log Group: This is where your log events will be stored.
2. Define a CloudWatch Log Metric Filter: Filters and extracts metrics from the specified log group based on a filter pattern.
3. Attach the Metric Filter to a Log Group: This makes the metric filter active and starts extracting metrics from the log group.

Below is a detailed example using infrastructure as code:

import * as pulumi from "@pulumi/pulumi";
import * as aws from "@pulumi/aws";

// Step 1: Create a CloudWatch Log Group
const exampleLogGroup = new aws.cloudwatch.LogGroup("example_log_group", {
    name: "example-log-group",
    retentionInDays: 14,
});
// Step 3: Define a CloudWatch Log Metric Filter
const exampleMetricFilter = new aws.cloudwatch.LogMetricFilter("example_metric_filter", {
    name: "example-metric-filter",
    logGroupName: exampleLogGroup.name,
    pattern: "{ $.errorCode = "404" }",
    metricTransformation: {
        name: "404Errors",
        namespace: "LogMetrics",
        value: "1",
    },
});
export const logGroupName = exampleLogGroup.name;
export const metricFilterName = exampleMetricFilter.name;

Key Points

• CloudWatch Log Group: Used to store log events.
• Metric Filter: Pattern that determines which log events to capture for metrics.
• Metric Transformation: Defines how the captured log events are transformed into CloudWatch metrics.

Summary

We created a CloudWatch Log Group to store logs, defined a Metric Filter to capture specific log events, and set up a Metric Transformation to generate metrics from those logs. This allows us to monitor specific log patterns by analyzing the metrics.