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etcd4.go
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etcd4.go
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// Copyright 2015 CoreOS, Inc.
//
// 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 migrate
import (
"fmt"
"log"
"os"
"path"
pb "github.com/coreos/etcd/etcdserver/etcdserverpb"
"github.com/coreos/etcd/pkg/pbutil"
"github.com/coreos/etcd/pkg/types"
raftpb "github.com/coreos/etcd/raft/raftpb"
"github.com/coreos/etcd/snap"
"github.com/coreos/etcd/wal"
"github.com/coreos/etcd/wal/walpb"
)
// We need an offset in leader election terms, because term 0 is special in 2.0.
const termOffset4to2 = 1
func snapDir4(dataDir string) string {
return path.Join(dataDir, "snapshot")
}
func logFile4(dataDir string) string {
return path.Join(dataDir, "log")
}
func cfgFile4(dataDir string) string {
return path.Join(dataDir, "conf")
}
func snapDir2(dataDir string) string {
return path.Join(dataDir, "snap")
}
func walDir2(dataDir string) string {
return path.Join(dataDir, "wal")
}
func Migrate4To2(dataDir string, name string) error {
// prep new directories
sd2 := snapDir2(dataDir)
if err := os.MkdirAll(sd2, 0700); err != nil {
return fmt.Errorf("failed creating snapshot directory %s: %v", sd2, err)
}
// read v0.4 data
snap4, err := DecodeLatestSnapshot4FromDir(snapDir4(dataDir))
if err != nil {
return err
}
cfg4, err := DecodeConfig4FromFile(cfgFile4(dataDir))
if err != nil {
return err
}
ents4, err := DecodeLog4FromFile(logFile4(dataDir))
if err != nil {
return err
}
nodeIDs := ents4.NodeIDs()
nodeID := GuessNodeID(nodeIDs, snap4, cfg4, name)
if nodeID == 0 {
return fmt.Errorf("Couldn't figure out the node ID from the log or flags, cannot convert")
}
metadata := pbutil.MustMarshal(&pb.Metadata{NodeID: nodeID, ClusterID: 0x04add5})
wd2 := walDir2(dataDir)
w, err := wal.Create(wd2, metadata)
if err != nil {
return fmt.Errorf("failed initializing wal at %s: %v", wd2, err)
}
defer w.Close()
// transform v0.4 data
var snap2 *raftpb.Snapshot
if snap4 == nil {
log.Printf("No snapshot found")
} else {
log.Printf("Found snapshot: lastIndex=%d", snap4.LastIndex)
snap2 = snap4.Snapshot2()
}
st2 := cfg4.HardState2()
// If we've got the most recent snapshot, we can use it's committed index. Still likely less than the current actual index, but worth it for the replay.
if snap2 != nil && st2.Commit < snap2.Metadata.Index {
st2.Commit = snap2.Metadata.Index
}
ents2, err := Entries4To2(ents4)
if err != nil {
return err
}
ents2Len := len(ents2)
log.Printf("Found %d log entries: firstIndex=%d lastIndex=%d", ents2Len, ents2[0].Index, ents2[ents2Len-1].Index)
// set the state term to the biggest term we have ever seen,
// so term of future entries will not be the same with term of old ones.
st2.Term = ents2[ents2Len-1].Term
// explicitly prepend an empty entry as the WAL code expects it
ents2 = append(make([]raftpb.Entry, 1), ents2...)
if err = w.Save(st2, ents2); err != nil {
return err
}
log.Printf("Log migration successful")
// migrate snapshot (if necessary) and logs
var walsnap walpb.Snapshot
if snap2 != nil {
walsnap.Index, walsnap.Term = snap2.Metadata.Index, snap2.Metadata.Term
ss := snap.New(sd2)
if err := ss.SaveSnap(*snap2); err != nil {
return err
}
log.Printf("Snapshot migration successful")
}
if err = w.SaveSnapshot(walsnap); err != nil {
return err
}
return nil
}
func GuessNodeID(nodes map[string]uint64, snap4 *Snapshot4, cfg *Config4, name string) uint64 {
var snapNodes map[string]uint64
if snap4 != nil {
snapNodes = snap4.GetNodesFromStore()
}
// First, use the flag, if set.
if name != "" {
log.Printf("Using suggested name %s", name)
if val, ok := nodes[name]; ok {
log.Printf("Assigning %s the ID %s", name, types.ID(val))
return val
}
if snapNodes != nil {
if val, ok := snapNodes[name]; ok {
log.Printf("Assigning %s the ID %s", name, types.ID(val))
return val
}
}
log.Printf("Name not found, autodetecting...")
}
// Next, look at the snapshot peers, if that exists.
if snap4 != nil {
//snapNodes := make(map[string]uint64)
//for _, p := range snap4.Peers {
//m := generateNodeMember(p.Name, p.ConnectionString, "")
//snapNodes[p.Name] = uint64(m.ID)
//}
for _, p := range cfg.Peers {
delete(snapNodes, p.Name)
}
if len(snapNodes) == 1 {
for nodename, id := range nodes {
log.Printf("Autodetected from snapshot: name %s", nodename)
return id
}
}
}
// Then, try and deduce from the log.
for _, p := range cfg.Peers {
delete(nodes, p.Name)
}
if len(nodes) == 1 {
for nodename, id := range nodes {
log.Printf("Autodetected name %s", nodename)
return id
}
}
return 0
}