MIDDLEWARE_INVOCATION_TIMEOUT

The MIDDLEWARE_INVOCATION_TIMEOUT error occurs when an Edge Middleware takes longer than the allowed execution time to complete or doesn't send a response chunk for a certain amount of time. This can be caused by long-running processes within the function or external dependencies that fail to respond in a timely manner.

If your backend API takes time to respond, we recommend streaming the response to avoid the idle timeout.

To troubleshoot this error, follow these steps:

1. Check application logs: Review the application logs to identify any specific errors related to the Edge Middleware being invoked. They can be found at the host URL under the /_logs path
2. Review function code: Inspect the Edge Middleware code for any long-running operations or infinite loops that could cause a timeout
3. Verify return value: Ensure the function returns a response within the specified time limit of 25 seconds
4. Optimize external calls: If the function makes calls to external services or APIs, ensure they are optimized and responding quickly. Consider specifying a fetch timeout for external calls using AbortSignal.timeout.
5. Consider streaming data: If the function is processing large amounts of data, consider using a streaming approach to avoid timeouts
6. Implement error handling: Add error handling in the function to manage timeouts and other exceptions effectively