Question

A development team runs a high-volume order-processing function on AWS Lambda. They want to publish custom business metrics (such as orders processed and payment failures) to CloudWatch without adding synchronous PutMetricData API calls that increase function duration and cost. The metrics must also remain queryable alongside the detailed structured log context that produced them. What is the MOST efficient way to meet these requirements?

Accepted Answer

Write log entries using the CloudWatch Embedded Metric Format (EMF) to stdout so CloudWatch automatically extracts the custom metrics from the structured logs.

Answer

Call the CloudWatch PutMetricData API asynchronously at the end of each invocation to publish the custom metrics.

Answer

Create a CloudWatch Logs metric filter on the Lambda log group to match plain-text log lines and increment custom metrics.

Answer

Install the CloudWatch agent as a Lambda extension and configure it to collect StatsD metrics from the function.