AWS Lambda By default, all native logs within a Lambda function are stored in the function execution result within Lambda. Additionally, if you would like to review log information immediately after executing a function, invoking the Lambda function with the LogType parameter will retrieve the last 4KB of log data generated by the function. This information is returned in the x-amz-log-results header in the HTTP response.
While these methods are great ways to test and debug issues associated with individual function calls, they do not do much by way of analysis or alerting. Thankfully, the log data that is stored in the Lambda function result is also stored in CloudWatch, Amazon’s log aggregation service. To access the CloudWatch logs for a given function, you will need to know the log group and log stream names, which can be retrieved by adding them to the function call logs and retrieving them in the x-amz-log-results response as mentioned above. As an example, this context can be retrieved and logged in Node.js like so:
console.log(‘logGroupName =’, context.log_group_name); console.log(‘logStreamName =’, context.log_stream_name);