CloudWatch Metrics and CloudWatch Logs for Lambda Functions
You can use CloudWatch metrics to monitor, in real time, the CloudFront requests that trigger Lambda functions. You can also use CloudWatch Logs to get aggregate data. There's no additional charge for metrics or logs.
CloudWatch Metrics
When you create a trigger for a CloudFront event, Lambda begins to send metrics to
CloudWatch automatically. Metrics are
available for all Lambda Regions. The name of each metric is
/aws/lambda/us-east-1.function-name, where
function-name is the name that you gave to the function when you created it. CloudWatch
sends metrics to the Region that's closest to the location where the function
is executed.
For more information about CloudWatch metrics, see the Amazon CloudWatch User Guide.
CloudWatch Logs
When you create a trigger, Lambda automatically starts to send data to CloudWatch Logs about the CloudFront requests that trigger Lambda functions. You can access the log files by using the CloudFront console in the AWS Management Console or use CloudWatch Logs tools directly to access the logs.
Lambda creates CloudWatch Logs log streams in the CloudWatch Logs Regions closest
to the locations where the function is executed.
The log group name is formatted as: /aws/lambda/us-east-1.function-name,
where function-name is the name that you gave to the function when you created it.
Note
Lambda@Edge throttles logs based on the request volume and the size of logs.
You must review CloudWatch log files in the correct AWS Region to see the log files created when CloudFront executed your Lambda function. To see the Regions where your Lambda@Edge function is receiving traffic, view graphs of metrics for the function on the CloudFront console on the AWS Management Console. Metrics are displayed for each AWS Region. On the same page, you can choose a Region and then view log files for that Region so that you can investigate issues.
To learn more about how to use CloudWatch Logs with Lambda functions, see the following:
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For more information about viewing graphs in the Monitoring section of the CloudFront console, see Monitoring CloudFront and Setting Alarms.
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For information about the permissions required to send data to CloudWatch Logs, see Setting IAM Permissions and Roles for Lambda@Edge in the IAM User Guide.
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For information about adding logging to a Lambda function, see Function Logging in Node.js or Function Logging in Python in the AWS Lambda Developer Guide.
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For information about CloudWatch Logs limits, see Limits in the Amazon CloudWatch Logs User Guide.
