grpc-web: Error callback never invoked for some classes of server response.

Hi @y3llowcake ! I don’t kown if my problem is in the scope of this issue but here is the explanation: I have a gRPC server written in Go, my proxy is envoy, and I use the JS client of grpc-web in this mode: import_style=commonjs,mode=grpcwebtext.

If my server resturns a gRPC error, the JS Client don’t handle the error. For example, this call returns a valid GRPC error in headers:

but my client don’t handle it:

const signUpCall = accountClient.signUp(accountRequest, {}, (err, res) => {
    if (err) {
        console.error(err);
    }
    console.log(res);
});

signUpCall.on('status', status => console.log('status', status));
signUpCall.on('data', d => console.log('data', d));
signUpCall.on('end', d => console.log('end', d));
signUpCall.on('error', d => console.log('error', d));

(In this case, none of my console.log was called…)

What do you think ? 😃 Thanks !

@skyjia Could you let me know what exactly the incorrect configuration was? We have been stuck with this same problem in our app and seem to have a similar environment as you do.

Thanks in advance!

@aberasarte we have figured out the issue. It’s due to an incorrect configuration in our API gateway.

I’m running into the same issue while I’m debugging my implementation of a grpc-web server. If I return an incorrectly encoded response, the grpc-web Javascript client just drops it. Instead, I would expect to get a gRPC error response with code INTERNAL probably? I can provide a more detailed reproduction if that would be useful.

@aberasarte I changed the expose headers and restarted the envoy, this error callback is still never invoked.

expose_headers: grpc-status,grpc-message

package.json:

 "dependencies": {
    "google-protobuf": "^3.10.0",
    "grpc-web": "^1.0.7",
  },

   getUserProfile (accessToken, ouid) {
    const request = new ProtoUserAPI.GetUserProfileRequest()
    request.setOuid(ouid)
    request.setAccessToken(accessToken)

    const metadata = null

    const that = this

    return new Promise((resolve, reject) => {
      that.client.getUserProfile(request, metadata, (err, response) => {
        // #1 never go here when there is an error

        if (err) {
          reject(err.message)
        } else {
          // #2 go here when successful
          resolve(response)
        }
      })
    })
  }

The code never goes to #1 when there is an error reported from underlying gRPC service. I can see the grpc-status and grpc-message headers in HTTP response in Chrome devtool.

However, the code can go to #2 when the RPC call is successful.