From c791d13e28247ab706efba4a9643a1652261e3f7 Mon Sep 17 00:00:00 2001
From: Gyu-Ho Lee <gyuhox@gmail.com>
Date: Mon, 1 May 2017 14:12:40 -0700
Subject: [PATCH] embed: fix blocking Close before gRPC server start

If 'StartEtcd' returns before starting gRPC server
(e.g. mismatch snapshot, misconfiguration),
receiving from grpcServerC blocks forever. This patch
just closes the channel to not block on grpcServerC,
and proceeds to next stop operations in Close.

This was masking the issues in https://github.com/coreos/etcd/issues/7834

Signed-off-by: Gyu-Ho Lee <gyuhox@gmail.com>
---
 embed/etcd.go       | 16 +++++++++++++---
 embed/serve_test.go | 39 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 52 insertions(+), 3 deletions(-)
 create mode 100644 embed/serve_test.go

diff --git a/embed/etcd.go b/embed/etcd.go
index 4d23a04009c3..e1352098be1d 100644
--- a/embed/etcd.go
+++ b/embed/etcd.go
@@ -70,13 +70,21 @@ func StartEtcd(inCfg *Config) (e *Etcd, err error) {
 	if err = inCfg.Validate(); err != nil {
 		return nil, err
 	}
+	serving := false
 	e = &Etcd{cfg: *inCfg, stopc: make(chan struct{})}
 	cfg := &e.cfg
 	defer func() {
-		if e != nil && err != nil {
-			e.Close()
-			e = nil
+		if e == nil || err == nil {
+			return
+		}
+		if !serving {
+			// errored before starting gRPC server for serveCtx.grpcServerC
+			for _, sctx := range e.sctxs {
+				close(sctx.grpcServerC)
+			}
 		}
+		e.Close()
+		e = nil
 	}()
 
 	if e.Peers, err = startPeerListeners(cfg); err != nil {
@@ -134,9 +142,11 @@ func StartEtcd(inCfg *Config) (e *Etcd, err error) {
 	e.errc = make(chan error, len(e.Peers)+len(e.Clients)+2*len(e.sctxs))
 
 	e.Server.Start()
+
 	if err = e.serve(); err != nil {
 		return
 	}
+	serving = true
 	return
 }
 
diff --git a/embed/serve_test.go b/embed/serve_test.go
new file mode 100644
index 000000000000..3f947979552a
--- /dev/null
+++ b/embed/serve_test.go
@@ -0,0 +1,39 @@
+// Copyright 2017 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package embed
+
+import (
+	"io/ioutil"
+	"os"
+	"testing"
+
+	"github.com/coreos/etcd/auth"
+)
+
+// TestStartEtcdWrongToken ensures that StartEtcd with wrong configs returns with error.
+func TestStartEtcdWrongToken(t *testing.T) {
+	tdir, err := ioutil.TempDir(os.TempDir(), "token-test")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer os.RemoveAll(tdir)
+	os.TempDir()
+	cfg := NewConfig()
+	cfg.Dir = tdir
+	cfg.AuthToken = "wrong-token"
+	if _, err = StartEtcd(cfg); err != auth.ErrInvalidAuthOpts {
+		t.Fatalf("expected %v, got %v", auth.ErrInvalidAuthOpts, err)
+	}
+}