From 41757e7f78114c44f22d300863524fdd347b875b Mon Sep 17 00:00:00 2001
From: Jonathan Boulle <jonathanboulle@gmail.com>
Date: Fri, 7 Nov 2014 11:57:04 -0800
Subject: [PATCH] etcdserver: collapse shared readWAL logic

---
 etcdserver/force_cluster.go | 15 ++++-----------
 etcdserver/server.go        | 35 ++++++++++++++---------------------
 2 files changed, 18 insertions(+), 32 deletions(-)

diff --git a/etcdserver/force_cluster.go b/etcdserver/force_cluster.go
index d6c40a487..b0d1c8085 100644
--- a/etcdserver/force_cluster.go
+++ b/etcdserver/force_cluster.go
@@ -28,15 +28,8 @@ import (
 	"github.com/coreos/etcd/wal"
 )
 
-func restartAsStandaloneNode(cfg *ServerConfig, index uint64, snapshot *raftpb.Snapshot) (id types.ID, n raft.Node, w *wal.WAL) {
-	var err error
-	if w, err = wal.OpenAtIndex(cfg.WALDir(), index); err != nil {
-		log.Fatalf("etcdserver: open wal error: %v", err)
-	}
-	id, cid, st, ents, err := readWAL(w, index)
-	if err != nil {
-		log.Fatalf("etcdserver: read wal error: %v", err)
-	}
+func restartAsStandaloneNode(cfg *ServerConfig, index uint64, snapshot *raftpb.Snapshot) (types.ID, raft.Node, *wal.WAL) {
+	w, id, cid, st, ents := readWAL(cfg.WALDir(), index)
 	cfg.Cluster.SetID(cid)
 
 	// discard the previously uncommitted entries
@@ -60,8 +53,8 @@ func restartAsStandaloneNode(cfg *ServerConfig, index uint64, snapshot *raftpb.S
 	}
 
 	log.Printf("etcdserver: forcing restart of member %s in cluster %s at commit index %d", id, cfg.Cluster.ID(), st.Commit)
-	n = raft.RestartNode(uint64(id), 10, 1, snapshot, st, ents)
-	return
+	n := raft.RestartNode(uint64(id), 10, 1, snapshot, st, ents)
+	return id, n, w
 }
 
 // getIDs returns an ordered set of IDs included in the given snapshot and
diff --git a/etcdserver/server.go b/etcdserver/server.go
index 97b125fcf..a33f3c227 100644
--- a/etcdserver/server.go
+++ b/etcdserver/server.go
@@ -724,8 +724,6 @@ func GetClusterFromPeers(urls []string) (*Cluster, error) {
 
 func startNode(cfg *ServerConfig, ids []types.ID) (id types.ID, n raft.Node, w *wal.WAL) {
 	var err error
-	// TODO: remove the discoveryURL when it becomes part of the source for
-	// generating nodeID.
 	member := cfg.Cluster.MemberByName(cfg.Name)
 	metadata := pbutil.MustMarshal(
 		&pb.Metadata{
@@ -764,29 +762,24 @@ func getOtherPeerURLs(cl ClusterInfo, self string) []string {
 	return us
 }
 
-func restartNode(cfg *ServerConfig, index uint64, snapshot *raftpb.Snapshot) (id types.ID, n raft.Node, w *wal.WAL) {
-	var err error
-	// restart a node from previous wal
-	if w, err = wal.OpenAtIndex(cfg.WALDir(), index); err != nil {
-		log.Fatalf("etcdserver: open wal error: %v", err)
-	}
-	id, clusterID, st, ents, err := readWAL(w, index)
-	if err != nil {
-		log.Fatalf("etcdserver: read wal error: %v", err)
-	}
-	cfg.Cluster.SetID(clusterID)
+func restartNode(cfg *ServerConfig, index uint64, snapshot *raftpb.Snapshot) (types.ID, raft.Node, *wal.WAL) {
+	w, id, cid, st, ents := readWAL(cfg.WALDir(), index)
+	cfg.Cluster.SetID(cid)
+
 	log.Printf("etcdserver: restart member %s in cluster %s at commit index %d", id, cfg.Cluster.ID(), st.Commit)
-	n = raft.RestartNode(uint64(id), 10, 1, snapshot, st, ents)
-	return
+	n := raft.RestartNode(uint64(id), 10, 1, snapshot, st, ents)
+	return id, n, w
 }
 
-func readWAL(w *wal.WAL, index uint64) (id, cid types.ID, st raftpb.HardState, ents []raftpb.Entry, err error) {
-	var wmetadata []byte
-	wmetadata, st, ents, err = w.ReadAll()
-	if err != nil {
-		return
+func readWAL(waldir string, index uint64) (w *wal.WAL, id, cid types.ID, st raftpb.HardState, ents []raftpb.Entry) {
+	var err error
+	if w, err = wal.OpenAtIndex(waldir, index); err != nil {
+		log.Fatalf("etcdserver: open wal error: %v", err)
+	}
+	var wmetadata []byte
+	if wmetadata, st, ents, err = w.ReadAll(); err != nil {
+		log.Fatalf("etcdserver: read wal error: %v", err)
 	}
-
 	var metadata pb.Metadata
 	pbutil.MustUnmarshal(&metadata, wmetadata)
 	id = types.ID(metadata.NodeID)