CODEWITHSUNDEEP
google-cloud-platformgoogle-cloud-endpointsgrpcgrpc-web
Alexandre Thenorio
Alexandre Thenorio

Reputation: 2418

Google Endpoints + grpc-web

As seen in the changelog of the esp proxy for Google endpoints (https://github.com/cloudendpoints/esp/pull/283) support for grpc-web has been added for it.

I am however unable to get it to work. I deployed the esp with the following cors configuration

# Note: The following lines are included in a server block, so we cannot use all Nginx constructs here.
set $cors_expose_headers "";
set $cors_max_age "";

if ($request_method = 'OPTIONS') {
    set $cors_max_age 1728000;
    return 204;
}

if ($request_method = 'POST') {
    set $cors_expose_headers 'DNT,X-CustomHeader,Keep-Alive,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type,Content-Range,Range,content-transfer-encoding,custom-header-1,x-accept-content-transfer-encoding,x-accept-response-streaming,x-user-agent,x-grpc-web,grpc-timeout';
}

if ($request_method = 'GET') {
    set $cors_expose_headers 'DNT,X-CustomHeader,Keep-Alive,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type,Content-Range,Range,,content-transfer-encoding,custom-header-1,x-accept-content-transfer-encoding,x-accept-response-streaming,x-user-agent,x-grpc-web,grpc-timeout';
}

add_header 'Access-Control-Allow-Origin' '*';
add_header 'Access-Control-Allow-Methods' 'GET, POST, OPTIONS';
add_header 'Access-Control-Allow-Headers' 'DNT,X-CustomHeader,Keep-Alive,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type,Content-Range,Range,,content-transfer-encoding,custom-header-1,x-accept-content-transfer-encoding,x-accept-response-streaming,x-user-agent,x-grpc-web,grpc-timeout';
add_header 'Access-Control-Expose-Headers' $cors_expose_headers;
add_header 'Access-Control-Max-Age' $cors_max_age;

And then configured a GRPC Google endpoint.

When I attempt to send a grpc-web request to that endpoint, I can see that the OPTIONS request goes through but I get a 400 back on the actual request with the following response

{
 "code": 3,
 "message": "Unexpected token.\AAAAASIKAF5etnRlbkFw\n^",
 "details": [
  {
   "@type": "type.googleapis.com/google.rpc.DebugInfo",
   "stackEntries": [],
   "detail": "internal"
  }
 ]
}

I think this is coming back from Google Endpoints which leads to believe that grpc-web support might not be fully there yet.

Has anybody managed to get this working?

Upvotes: 3

Views: 806

Answers (1)

Alexandre Thenorio
Alexandre Thenorio

Reputation: 2418

Turns out that, as the conversation on the pull request linked in the question shows (and also tested by me later), the issue was me trying to use the grpc-web-text protocol which is not supported by Google cloud endpoints.

After some tests I can confirm that Google cloud endpoints does support grpc-web but only the binary wire format, which means no server streaming support, only unary calls

Upvotes: 5

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