Return codes.InvalidArgument to rather return HTTP 400 instead of HTTP 500

[pieterlouw]

Hi,

Currently if there's a conversion error on the request then the gateway return an HTTP 500 with the Go error in the HTTP Body.

Won't it be clearer to the API client user if a codes.InvalidArgument (that translate to HTTP 400) is returned rather?

Pieter

[achew22]

Pieter, this seems reasonable to me. Could you sign the CLA and add a test to verify the new behavior?

[pieterlouw]

Hi,
I've signed the CLA.

About the test, where exactly should I add one ?
https://github.com/grpc-ecosystem/grpc-gateway/blob/master/examples/integration_test.go
or
https://github.com/grpc-ecosystem/grpc-gateway/blob/master/protoc-gen-grpc-gateway/gengateway/template_test.go

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[achew22]

Generally I believe you should test it in the smallest size test that completely validates behavior. Since template.go is generating a string that is going to be compiled by the go compiler I don't know that we can fully test the functionality in template.go. Therefore, I think the test should go in integration.go. If you have a nifty trick for testing it in template.go I would love to learn.

[achew22]

Oh, I should also note that since you're modifying a template you will need to run make examples in the root directory to update all the example code with your change.

Thanks!

[pieterlouw]

Closing this as #409 have test case and examples