From 0814966ca2efee86a32a29be34751434b5944ffa Mon Sep 17 00:00:00 2001
From: Yicheng Qin <qycqycqycqycqyc@gmail.com>
Date: Mon, 8 Jun 2015 22:48:10 -0700
Subject: [PATCH] etcdserver: stop raft loop when receiving stop signal

When it waits for apply to be done, it should stop the loop if it
receives stop signal.

This helps to print out panic information. Before this PR, if the panic
happens when server loop is applying entries, server loop will wait for
raft loop to stop forever.
---
 etcdserver/raft.go      |  6 +++++-
 etcdserver/raft_test.go | 28 ++++++++++++++++++++++++++++
 2 files changed, 33 insertions(+), 1 deletion(-)

diff --git a/etcdserver/raft.go b/etcdserver/raft.go
index 040810a01..1d5231682 100644
--- a/etcdserver/raft.go
+++ b/etcdserver/raft.go
@@ -161,7 +161,11 @@ func (r *raftNode) run() {
 
 			r.s.send(rd.Messages)
 
-			<-apply.done
+			select {
+			case <-apply.done:
+			case <-r.stopped:
+				return
+			}
 			r.Advance()
 		case <-syncC:
 			r.s.sync(defaultSyncTimeout)
diff --git a/etcdserver/raft_test.go b/etcdserver/raft_test.go
index 0e49aef6c..d102771a0 100644
--- a/etcdserver/raft_test.go
+++ b/etcdserver/raft_test.go
@@ -18,9 +18,11 @@ import (
 	"encoding/json"
 	"reflect"
 	"testing"
+	"time"
 
 	"github.com/coreos/etcd/pkg/pbutil"
 	"github.com/coreos/etcd/pkg/types"
+	"github.com/coreos/etcd/raft"
 	"github.com/coreos/etcd/raft/raftpb"
 )
 
@@ -141,3 +143,29 @@ func TestCreateConfigChangeEnts(t *testing.T) {
 		}
 	}
 }
+
+func TestStopRaftWhenWaitingForApplyDone(t *testing.T) {
+	n := newReadyNode()
+	r := raftNode{
+		Node:        n,
+		applyc:      make(chan apply),
+		storage:     &storageRecorder{},
+		raftStorage: raft.NewMemoryStorage(),
+		transport:   &nopTransporter{},
+	}
+	r.s = &EtcdServer{r: r}
+	go r.run()
+	n.readyc <- raft.Ready{}
+	select {
+	case <-r.applyc:
+	case <-time.After(time.Second):
+		t.Fatalf("failed to receive apply struct")
+	}
+
+	r.stopped <- struct{}{}
+	select {
+	case <-r.done:
+	case <-time.After(time.Second):
+		t.Fatalf("failed to stop raft loop")
+	}
+}