API Gateway Mock Integration Fails with 500

Question

I have an API Gateway integration for a method/resource which works when I call it from the API but not when I actually call it:

$ aws apigateway test-invoke-method --rest-api-id $REST_API_ID \
    --resource-id $RESOURCE_ID --http-method GET | jq -r .log,.body

This works out fine and I get the following output:

Tue May 16 17:46:42 UTC 2017 : Starting execution for request: test-invoke-request
Tue May 16 17:46:42 UTC 2017 : HTTP Method: GET, Resource Path: /status.json
Tue May 16 17:46:42 UTC 2017 : Method request path: {}
Tue May 16 17:46:42 UTC 2017 : Method request query string: {}
Tue May 16 17:46:42 UTC 2017 : Method request headers: {}
Tue May 16 17:46:42 UTC 2017 : Method request body before transformations:
Tue May 16 17:46:42 UTC 2017 : Endpoint response body before transformations:
Tue May 16 17:46:42 UTC 2017 : Endpoint response headers: {}
Tue May 16 17:46:42 UTC 2017 : Method response body after transformations: { "statusCode": 200 }
Tue May 16 17:46:42 UTC 2017 : Method response headers: {Content-Type=application/json}
Tue May 16 17:46:42 UTC 2017 : Successfully completed execution
Tue May 16 17:46:42 UTC 2017 : Method completed with status: 200

{ "statusCode": 200 }

However, I cannot access this at my URL, which is api.naftuli.wtf/v1/status.json. I have stages defined at glhf, stable, and v1, so by replacing that, you will see different responses. I just simply want a dummy response that returns a 200 JSON blob.

My Terraform for the resources is here as a Gist. Hopefully this fully shows my API Gateway configuration.

If I test invoke this from the CLI or from the web console, I get back what is expected. However, if I curl this from my deployed API at api.naftuli.wtf, I don't get anything nice:

$ for stage in glhf stable v1 ; do 
>   url="https://api.naftuli.wtf/${stage}/status.json"
>   echo "${url}:" 
>   curl -i -H 'Content-Type: application/json' \
>     https://api.naftuli.wtf/${stage}/status.json
>   echo -e '\n
> done
https://api.naftuli.wtf/glhf/status.json:
HTTP/1.1 500 Internal Server Error
Content-Type: application/json
Content-Length: 36
Connection: keep-alive
Date: Tue, 16 May 2017 21:41:38 GMT
x-amzn-RequestId: 712ba52b-3a80-11e7-9fec-b79b62d3bf7f
X-Cache: Error from cloudfront
Via: 1.1 da7a5d0ed7f424609000879e43743066.cloudfront.net (CloudFront)
X-Amz-Cf-Id: hBwlbPCP9n2rlz53I-Qb9KoffHB_FoxUCZUaJYNnU3XhCWuMpQTP1Q==

{"message": "Internal server error"}

https://api.naftuli.wtf/stable/status.json:
HTTP/1.1 403 Forbidden
Content-Type: application/json
Content-Length: 23
Connection: keep-alive
Date: Tue, 16 May 2017 21:41:38 GMT
x-amzn-RequestId: 71561066-3a80-11e7-9b00-6700be628328
x-amzn-ErrorType: ForbiddenException
X-Cache: Error from cloudfront
Via: 1.1 0c146399837c7d36c1f0f9d2636f8cf8.cloudfront.net (CloudFront)
X-Amz-Cf-Id: ITX765xD8s4sNuOdXaJ2kPvqPo-w_dsQK3Sq_No130FAHxFuoVhO8w==

{"message":"Forbidden"}

https://api.naftuli.wtf/v1/status.json:
HTTP/1.1 500 Internal Server Error
Content-Type: application/json
Content-Length: 36
Connection: keep-alive
Date: Tue, 16 May 2017 21:41:39 GMT
x-amzn-RequestId: 7185fa99-3a80-11e7-a3b1-2f9e659fc361
X-Cache: Error from cloudfront
Via: 1.1 586f1a150b4ba39f3a668b8055d4d5ea.cloudfront.net (CloudFront)
X-Amz-Cf-Id: dvnOa1s-YlwLSNzBfVyx5tSL6XrjFJM4_fES7MyTofykB3ReU5R1fg==

{"message": "Internal server error"}

My understanding of stages were that they were additional path prefixes to the base path under which all API resources were available. If I had a stage called v1 with a path of /v1, I'd expect that an API Gateway resource for status.json will be basically mapped under /v1, yielding /v1/status.json.

I may be misunderstanding how API Gateway base path mappings and stages work, but CloudWatch tells me that the call is at least happening, though failing for some obscure reason:

21:41:39(c5be3842-6af4-4725-a34f-d6eea8042d17) Verifying Usage Plan for request: c5be3842-6af4-4725-a34f-d6eea8042d17. API Key: API Stage: tcips69qx2/prod_v1
21:41:39(c5be3842-6af4-4725-a34f-d6eea8042d17) API Key authorized because method 'GET /status.json' does not require API Key. Request will not contribute to throttle or quota limits
21:41:39(c5be3842-6af4-4725-a34f-d6eea8042d17) Usage Plan check succeeded for API Key and API Stage tcips69qx2/prod_v1
21:41:39(c5be3842-6af4-4725-a34f-d6eea8042d17) Starting execution for request: c5be3842-6af4-4725-a34f-d6eea8042d17
21:41:39(c5be3842-6af4-4725-a34f-d6eea8042d17) HTTP Method: GET, Resource Path: /v1/status.json
21:41:39(c5be3842-6af4-4725-a34f-d6eea8042d17) Execution failed due to configuration error: statusCode should be an integer which defined in request template
21:41:39(c5be3842-6af4-4725-a34f-d6eea8042d17) Method completed with status: 500

Apparently only traffic across the V1 stage is getting through to CloudWatch logs. I have a misconfiguration somewhere and I can't seem to find it.

Answer 1

With Mock Integration Amazon API Gateway there are 2 common reasons for 500 Internal Server error.

1. Check the mapping template in Integration Request and ensure that you are passing statusCode as an integer to the MOCK Integration endpoint.

   { "statusCode": <Integer_Status_code> }

Note: Make sure that status code is passed as integer not string.

Correct : 200 Incorrect : "200"

2. Mock Integrations do not support the binary content. If the API is enabled with bixnary support and has application/json or */* set as binaryMediaTypes, MOCK Integration endpoints would throw a 500 Internal server error when trying to transform the content.

   A workaround is to update the contentHandling property of the MOCK Integration to CONVERT_TO_TEXT

Read more here :- https://cloudnamaste.com/500-internal-server-error-mock-integration/

Answer 2

Can you try and change you request template in the integration request setup to this:

{
  "statusCode": 200
}

API Gateway looks for the status code to return in the response in your integration request template. The response is generated by the mapping template in the integration response. I can see from your terraform setup that you are loading the output json file in the integration request template. This is content API Gateway does not expect.