AWS Lambda is a popular serverless compute service that allows developers to run code in response to events without worrying about infrastructure management. When working with Lambda, logging is an essential practice to help debug issues and monitor performance. In this article, we will cover the best practices for logging with AWS Lambda to help you optimize your application’s performance.
Why is AWS Lambda logging important?
AWS Lambda logging is important for several reasons. First, logging provides a way to troubleshoot issues and diagnose errors in your Lambda functions. When an error occurs, logging can help you identify the root cause of the issue and take corrective action.
Second, logging can help you monitor the performance of your Lambda functions. By logging important information, such as execution time and resource utilization, you can identify performance bottlenecks and optimize your functions for better performance.
Third, logging can provide important insights into how your application is being used. By logging information such as user requests and application usage, you can gain insights into how your application is being used and identify areas for improvement.
Finally, logging is often required for compliance purposes, such as auditing and regulatory compliance. By logging important events and activities, you can ensure that your application meets the necessary compliance requirements.
Top 10 AWS Lambda Logging Best Practices
Let’s learn 10 AWS Lambda logging best practices.

1. Use AWS CloudWatch Logs for Logging
CloudWatch Logs is a fully managed service that makes it easy to store, access, and monitor logs from Lambda functions. By default, Lambda logs all output to CloudWatch Logs, which makes it easy to access and analyze logs later on. It’s also easy to set up log retention policies to automatically delete old logs after a certain period.
2. Log Important Information
When logging with Lambda, it’s important to log the right information to help debug issues and monitor performance. Log important information such as errors, warnings, and debug information that may be useful in troubleshooting. You can also log custom information that’s specific to your application to help monitor performance and usage.
3. Use Log Levels
Log levels are an effective way to categorize different types of log messages based on their severity. For example, you can use log levels to categorize messages as info, warning, error, or critical. By using log levels, you can easily filter and analyze logs based on their severity.
4. Include Request IDs
When using Lambda with other AWS services, such as API Gateway or EventBridge, it’s important to include the request ID in your logs. The request ID is a unique identifier for each request that allows you to track the flow of requests through your application. By including the request ID in your logs, you can easily trace requests through your application and troubleshoot any issues that arise.
5. Use Structured Logging
Structured logging is a technique that allows you to log data in a structured format, such as JSON. By using structured logging, you can easily parse and analyze logs using tools such as Amazon Elasticsearch. Structured logging also makes it easier to search and filter logs based on specific criteria.
6. Log to Different Streams
When working with Lambda, you can log to different streams based on different criteria. For example, you can log to different streams based on log level or based on the type of event that triggered the Lambda function. This makes it easy to filter and analyze logs based on specific criteria.
7. Use Environment Variables
Environment variables are a great way to store configuration information, such as log levels or log retention policies. By using environment variables, you can easily configure your Lambda function’s logging behavior without changing your code.
8. Monitor Log Metrics
Monitoring log metrics is an effective way to measure the health and performance of your Lambda function. By monitoring metrics such as log volume, log size, and log latency, you can identify issues and optimize your application’s performance.
9. Set Up Alerts
Setting up alerts for your Lambda function’s logs is an effective way to proactively monitor your application’s health. You can set up alerts based on specific log events, log levels, or log metrics. This allows you to quickly identify and address any issues that arise.
10. Use a Logging Framework
Using a logging framework, such as Log4j or Python’s logging module, can help you standardize your logging practices and make it easier to maintain your application’s logging behavior. Logging frameworks also provide advanced features, such as log rotation and compression.
Conclusion
Logging is an essential practice when working with AWS Lambda. By following these best practices, you can optimize your application’s performance, troubleshoot issues, and proactively monitor your application’s health. With CloudWatch Logs and the right logging practices, you can confidently build and maintain robust serverless applications.