13.12. How to Configure AWS Lambda: Error Handling in Lambda Functions

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13.12. How to Configure AWS Lambda: Error Handling in Lambda Functions

AWS Lambda is a service that lets you run your code without provisioning or managing servers. It runs your code only when needed and automatically scales from a few requests per day to thousands per second. In this chapter, we will focus on a crucial aspect of AWS Lambda, which is error handling in Lambda functions.

Understanding Errors in Lambda Functions

Before we dive into setting up error handling, it's important to understand the types of errors that can occur in a Lambda function. Errors can be divided into two categories: handled errors and unhandled errors.

Handled errors are those that you identify and manage in the function code. For example, if you are making an API call and you receive an HTTP 404 error, you can capture that error and handle it accordingly. Unhandled errors, on the other hand, are errors that occur outside of your control, such as infrastructure problems or runtime exceptions.

Configuring Error Handling

To configure error handling in Lambda functions, you will need to understand and use three main components: the function code, timeout settings, and retry policies.

Function Code

In your function code, you must include logic to handle handled errors. This may involve using try/catch blocks to catch exceptions, checking for errors after API calls, and so on. The goal is to ensure that your code can gracefully handle expected errors.

Timeout Settings

AWS Lambda allows you to set a timeout for your function to run. If the function does not complete within this time, Lambda ends execution and returns an error. It's important to set an appropriate timeout for your function, taking into account the time it normally takes to run and the time you are willing to allow it to run in case of delays or problems.

Retry Policies

AWS Lambda has a built-in retry policy that tries to run your function again if it fails. You can configure the number of attempts and the interval between them. This can be useful for dealing with temporary errors, such as network or infrastructure issues.

Monitoring Errors

In addition to configuring error handling, it's important to monitor your Lambda function to quickly identify and resolve issues. AWS Lambda provides several monitoring tools, including CloudWatch logs, X-Ray tracing, and CloudWatch metrics.

CloudWatch logs allow you to see the details of each function execution, including any errors that occurred. X-Ray tracing provides a detailed view of your function's behavior, allowing you to see where time is being spent and where errors are occurring. CloudWatch metrics provide a high-level view of your function's performance, including the number of errors, invocations, and execution time.

Conclusion

In summary, error handling in Lambda functions is a crucial aspect of configuring AWS Lambda. By understanding error types, properly configuring error handling, and monitoring your function, you can ensure that your Lambda function is robust and reliable.

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5413.13. How to Configure AWS Lambda: Versioning and Aliasing Lambda Functions