apigateway http v2 integration with Lambda

When you're experiencing a 500 Internal Server Error with your HTTP API v2 Lambda integration and seeing API Gateway logs but no Lambda logs, this suggests that API Gateway is unable to invoke your Lambda function properly. Here are some troubleshooting steps you can take:

1. Check your logs thoroughly:

• Add $context.integrationErrorMessage to your API Gateway logging format
• Also include $context.error.message and $context.error.responseType for more detailed error information
• View the latest log stream in CloudWatch to identify the specific issue

2. Verify permissions:

• Ensure API Gateway has explicit permission to invoke your Lambda function
• You may need to add a resource-based policy to your Lambda function that grants API Gateway the necessary permissions
• Even if you think the role settings are correct, this is a common issue that might not show clear error messages

3. Check Lambda authorizer issues (if you're using one):

• If API Gateway can't invoke your Lambda authorizer or if the authorizer returns an invalid response format, clients will receive a 500 error
• Since you mentioned authorization passed, this might not be the issue, but it's worth checking the authorizer response format

4. Test the Lambda function directly:

• Invoke your Lambda function directly through the Lambda console to verify it works independently of API Gateway
• This can help determine if the issue is with the function itself or the integration

5. Verify deployment:

• Make sure you've properly deployed your API after making any changes
• Sometimes changes to integrations require redeployment to take effect

If you're still experiencing issues after these steps, you might need to examine your Lambda function code for potential errors or check if there are any account-specific configurations affecting your setup.
Sources
Control access to HTTP APIs with AWS Lambda authorizers - Amazon API Gateway
Troubleshooting issues with HTTP API Lambda integrations - Amazon API Gateway
Creating api gateway api from openapi specification with lambda integration does not create triggers | AWS re:Post