Question

A developer is investigating an increase in HTTP 500 errors reported by an application running on AWS Lambda behind API Gateway. The Lambda function writes structured JSON logs (including a 'level' field and 'errorType' field) to Amazon CloudWatch Logs. The developer needs to quickly identify which specific error type is most frequently associated with the failures over the last hour, without exporting logs to another service. What is the FASTEST way to do this?

Accepted Answer

Run a CloudWatch Logs Insights query against the function's log group that filters where level = 'ERROR', then uses stats count(*) by errorType and sorts by the count in descending order

Answer

Create a CloudWatch metric filter on the log group and wait for a new custom metric to accumulate data points before graphing it

Answer

Enable AWS X-Ray active tracing and inspect the service map to count error types across recent traces

Answer

Stream the log group to Amazon S3 with a subscription filter and query the objects using Amazon Athena