mirror of
https://github.com/etcd-io/etcd.git
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f59da0e453
Backup process should be able to read all WALs until io.EOF to generate a point-in-time backup. Our WAL file is append-only. And the backup process will lock all files before start reading, which can prevent the gc routine from removing any files in the middle.
101 lines
2.9 KiB
Go
101 lines
2.9 KiB
Go
// Copyright 2015 CoreOS, Inc.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package command
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import (
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"fmt"
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"log"
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"os"
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"path"
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"time"
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"github.com/coreos/etcd/Godeps/_workspace/src/github.com/codegangsta/cli"
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"github.com/coreos/etcd/etcdserver/etcdserverpb"
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"github.com/coreos/etcd/pkg/idutil"
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"github.com/coreos/etcd/pkg/pbutil"
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"github.com/coreos/etcd/snap"
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"github.com/coreos/etcd/wal"
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"github.com/coreos/etcd/wal/walpb"
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)
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func NewBackupCommand() cli.Command {
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return cli.Command{
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Name: "backup",
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Usage: "backup an etcd directory",
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Flags: []cli.Flag{
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cli.StringFlag{Name: "data-dir", Value: "", Usage: "Path to the etcd data dir"},
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cli.StringFlag{Name: "backup-dir", Value: "", Usage: "Path to the backup dir"},
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},
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Action: handleBackup,
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}
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}
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// handleBackup handles a request that intends to do a backup.
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func handleBackup(c *cli.Context) {
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srcSnap := path.Join(c.String("data-dir"), "member", "snap")
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destSnap := path.Join(c.String("backup-dir"), "member", "snap")
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srcWAL := path.Join(c.String("data-dir"), "member", "wal")
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destWAL := path.Join(c.String("backup-dir"), "member", "wal")
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if err := os.MkdirAll(destSnap, 0700); err != nil {
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log.Fatalf("failed creating backup snapshot dir %v: %v", destSnap, err)
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}
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ss := snap.New(srcSnap)
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snapshot, err := ss.Load()
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if err != nil && err != snap.ErrNoSnapshot {
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log.Fatal(err)
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}
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var walsnap walpb.Snapshot
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if snapshot != nil {
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walsnap.Index, walsnap.Term = snapshot.Metadata.Index, snapshot.Metadata.Term
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newss := snap.New(destSnap)
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if err := newss.SaveSnap(*snapshot); err != nil {
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log.Fatal(err)
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}
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}
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w, err := wal.OpenForRead(srcWAL, walsnap)
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if err != nil {
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log.Fatal(err)
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}
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defer w.Close()
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wmetadata, state, ents, err := w.ReadAll()
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switch err {
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case nil:
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case wal.ErrSnapshotNotFound:
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fmt.Printf("Failed to find the match snapshot record %+v in wal %v.", walsnap, srcWAL)
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fmt.Printf("etcdctl will add it back. Start auto fixing...")
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default:
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log.Fatal(err)
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}
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var metadata etcdserverpb.Metadata
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pbutil.MustUnmarshal(&metadata, wmetadata)
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idgen := idutil.NewGenerator(0, time.Now())
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metadata.NodeID = idgen.Next()
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metadata.ClusterID = idgen.Next()
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neww, err := wal.Create(destWAL, pbutil.MustMarshal(&metadata))
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if err != nil {
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log.Fatal(err)
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}
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defer neww.Close()
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if err := neww.Save(state, ents); err != nil {
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log.Fatal(err)
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}
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if err := neww.SaveSnapshot(walsnap); err != nil {
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log.Fatal(err)
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}
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}
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