CODEWITHSUNDEEP
aws-lambdaaws-api-gateway
Jim ReesPotter
Jim ReesPotter

Reputation: 465

AWS API Gateway Lambda error regex not working?

I'm trying to process the response from an API gateway -> Lambda -> API gateway exchange, and I can't get the Integration Response to process correctly.

I have 2 API Gateway integration responses defined using the following Lambda Error Regexes:

.*e.* -> method response status 200 (for testing only)
.*500.* -> method response status 500
(no default mapping)

My Lambda returns the following:

if (err)
      callback(null, {
        statusCode: 500,
        message: "commit ID failed - ID already present"
      });

    else
      callback(null, {
        statusCode: 200,
        message: "new ID committed"
      });

So the response from Lambda should always have some data in it.

When I run an API Gateway test it fails to hit either of the rules:

Sat Jun 20 07:49:56 UTC 2020 : Received response. Status: 200, Integration latency: 122 ms
Sat Jun 20 07:49:56 UTC 2020 : Endpoint response headers: {Date=Sat, 20 Jun 2020 07:49:56 GMT, Content-Type=application/json, Content-Length=68, Connection=keep-alive, x-amzn-RequestId=d7556a95-2ff9-4cf2-9e61-cc89484f6548, x-amzn-Remapped-Content-Length=0, X-Amz-Executed-Version=$LATEST, X-Amzn-Trace-Id=root=1-5eedbfa4-0ddb3f5e0882fbf1cd7e4674;sampled=0}
Sat Jun 20 07:49:56 UTC 2020 : Endpoint response body before transformations: {"statusCode":500,"message":"commit ID failed - ID already present"}
Sat Jun 20 07:49:56 UTC 2020 : Execution failed due to configuration error: No match for output mapping and no default output mapping configured. Endpoint Response Status Code: 200

If I change the Lambda Error Regexes:

.* matches responses from lambda
.+ doesn't match any responses from lambda

so I think this suggests that whatever field passed to Lambda error regex processing is empty - am I correct, and if so, how do I set a value for it in the Lambda response?

thanks in advance,

Jim

Upvotes: 0

Views: 1111

Answers (1)

Jim ReesPotter
Jim ReesPotter

Reputation: 465

Worked this out - my mistake was in the Lambda function - use callback("error message") for an error, callback(null, "success message") for a success. The API integration response Lambda Error Regex only processes the error (the clue is in the name I guess). So this works:

if (err)
   callback("commit ID failed - ID already present");
else
   callback(null, {
      statusCode: 200,
      message: "new ID committed"
   });

Now works with a Lambda Error Regex of eg .failed.

Upvotes: 0

Related Questions