*: fix 'gogo/protobuf' compatibility issue

[gyuho]

• Fix Enums are not parsed correctly by v3alpha API when sent as JSON #5942
• Partial fix for watch over grpc-gateway #5865

[gyuho]

Partial fix for #5865

because...

Currently

curl -L http://localhost:2379/v3alpha/watch -X POST -d '{"create_request": {"key": "Zm9v"}}'

wouldn't work, with the server complaining this error in this code https://github.com/coreos/etcd/blob/master/etcdserver/etcdserverpb/rpc.pb.gw.go#L92-L93:

2016/07/18 09:24:36 Failed to decode request: EOF

Work-around to make watch work:

diff --git a/etcdserver/etcdserverpb/rpc.pb.gw.go b/etcdserver/etcdserverpb/rpc.pb.gw.go
index 4ee9685..1bdd637 100644
--- a/etcdserver/etcdserverpb/rpc.pb.gw.go
+++ b/etcdserver/etcdserverpb/rpc.pb.gw.go
@@ -10,8 +10,11 @@ It translates gRPC into RESTful JSON APIs.
 package etcdserverpb

 import (
+       "fmt"
        "io"
+       "io/ioutil"
        "net/http"
+       "strings"

        "github.com/golang/protobuf/proto"
        "github.com/grpc-ecosystem/grpc-gateway/runtime"
@@ -86,11 +89,14 @@ func request_Watch_Watch_0(ctx context.Context, marshaler runtime.Marshaler, cli
                grpclog.Printf("Failed to start streaming: %v", err)
                return nil, metadata, err
        }
-       dec := marshaler.NewDecoder(req.Body)
+       bts, _ := ioutil.ReadAll(req.Body)
+       fmt.Println(string(bts))
+
+       dec := marshaler.NewDecoder(strings.NewReader(string(bts)))
        handleSend := func() error {
                var protoReq WatchRequest
                err = dec.Decode(&protoReq)
-               if err != nil {
+               if err != nil && err != io.EOF {
                        grpclog.Printf("Failed to decode request: %v", err)
                        return err
                }

string(bts) here is {"create_request": {"key": "Zm9v"}}

and with additional error checking of err != io.EOF, everything works fine...

We need to find some ways to make dec.Decode handle io.EOF.

Will report upstream.

/cc @heyitsanthony @xiang90

[heyitsanthony]

lgtm

[gyuho]

merging after all greens. thanks.

[gyuho]

Failure not related

--- FAIL: TestEmbedEtcd (1.13s)
    embed_test.go:78: 5: expected success, got error listen tcp 127.0.0.1:40026: bind: address already in use

Already reported in open issue https://github.com/coreos/etcd/issues/5953.

[xiang90]

@gyuho Why do we sent a zero length request at the first place? The request you sent should not be a zero length one. I suspect that the jsonpb -> proto thing still not working correctly?