Monitoring Logs of a Lambda Function

Monitoring Logs of a Lambda Function

1. Access the Lambda Function

• Go to the AWS Console
• Navigate to the Lambda service
• Select the function you want to view logs for

2. Click on the “Monitor” tab

• In the Lambda function interface → click on the Monitor tab
• Then click on View CloudWatch Logs

3. View Detailed Logs

• Once you’re on the Log events screen, select the latest log stream (based on timestamp)

• Here, you will see logs like:

• Analysis:
  • INIT_START: Appears when the Lambda starts for the first time (cold start); shows the runtime version used (e.g., Python 3.11), and the actual runtime ARN. This does not appear on every invocation—only when a new container is created.
  • START: Indicates the Lambda function has begun processing a new request includes:
    • RequestId: A unique ID for each invocation
    • Version: The version of the Lambda function being executed ($LATEST is the default).
  • END: Indicates the Lambda function has finished processing the request, with the same RequestId as START.
  • REPORT: Displays performance metrics:
    • Duration: Actual execution time (e.g., 490.34 ms)
    • Billed Duration: AWS rounds up to the nearest millisecond for billing (491 ms)
    • Memory Size: Configured memory for the function (128 MB)
    • Max Memory Used: Actual memory used during that invocation (e.g., 58 MB)