ctlv2: save v3 db with v2 data using --with-v3

Also strips out v3 data if not given --with-v3.

etcdctl/ctlv2/command/backup_command.go

@@ -15,18 +15,25 @@
 package command
 
 import (
-	"fmt"
+	"encoding/binary"
 	"log"
+	"os"
+	"path"
 	"path/filepath"
+	"regexp"
 	"time"
 
 	"github.com/coreos/etcd/etcdserver/etcdserverpb"
+	"github.com/coreos/etcd/etcdserver/membership"
 	"github.com/coreos/etcd/pkg/fileutil"
 	"github.com/coreos/etcd/pkg/idutil"
 	"github.com/coreos/etcd/pkg/pbutil"
+	"github.com/coreos/etcd/raft/raftpb"
 	"github.com/coreos/etcd/snap"
 	"github.com/coreos/etcd/wal"
 	"github.com/coreos/etcd/wal/walpb"
+
+	bolt "github.com/coreos/bbolt"
 	"github.com/urfave/cli"
 )
 
@@ -40,6 +47,7 @@ func NewBackupCommand() cli.Command {
 			cli.StringFlag{Name: "wal-dir", Value: "", Usage: "Path to the etcd wal dir"},
 			cli.StringFlag{Name: "backup-dir", Value: "", Usage: "Path to the backup dir"},
 			cli.StringFlag{Name: "backup-wal-dir", Value: "", Usage: "Path to the backup wal dir"},
+			cli.BoolFlag{Name: "with-v3", Usage: "Backup v3 backend data"},
 		},
 		Action: handleBackup,
 	}
@@ -50,6 +58,7 @@ func handleBackup(c *cli.Context) error {
 	var srcWAL string
 	var destWAL string
 
+	withV3 := c.Bool("with-v3")
 	srcSnap := filepath.Join(c.String("data-dir"), "member", "snap")
 	destSnap := filepath.Join(c.String("backup-dir"), "member", "snap")
 
@@ -68,12 +77,36 @@ func handleBackup(c *cli.Context) error {
 	if err := fileutil.CreateDirAll(destSnap); err != nil {
 		log.Fatalf("failed creating backup snapshot dir %v: %v", destSnap, err)
 	}
+
+	walsnap := saveSnap(destSnap, srcSnap)
+	metadata, state, ents := loadWAL(srcWAL, walsnap, withV3)
+	saveDB(filepath.Join(destSnap, "db"), filepath.Join(srcSnap, "db"), state.Commit, withV3)
+
+	idgen := idutil.NewGenerator(0, time.Now())
+	metadata.NodeID = idgen.Next()
+	metadata.ClusterID = idgen.Next()
+
+	neww, err := wal.Create(destWAL, pbutil.MustMarshal(&metadata))
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer neww.Close()
+	if err := neww.Save(state, ents); err != nil {
+		log.Fatal(err)
+	}
+	if err := neww.SaveSnapshot(walsnap); err != nil {
+		log.Fatal(err)
+	}
+
+	return nil
+}
+
+func saveSnap(destSnap, srcSnap string) (walsnap walpb.Snapshot) {
 	ss := snap.New(srcSnap)
 	snapshot, err := ss.Load()
 	if err != nil && err != snap.ErrNoSnapshot {
 		log.Fatal(err)
 	}
-	var walsnap walpb.Snapshot
 	if snapshot != nil {
 		walsnap.Index, walsnap.Term = snapshot.Metadata.Index, snapshot.Metadata.Term
 		newss := snap.New(destSnap)
@@ -81,7 +114,10 @@ func handleBackup(c *cli.Context) error {
 			log.Fatal(err)
 		}
 	}
+	return walsnap
+}
 
+func loadWAL(srcWAL string, walsnap walpb.Snapshot, v3 bool) (etcdserverpb.Metadata, raftpb.HardState, []raftpb.Entry) {
 	w, err := wal.OpenForRead(srcWAL, walsnap)
 	if err != nil {
 		log.Fatal(err)
@@ -91,28 +127,130 @@ func handleBackup(c *cli.Context) error {
 	switch err {
 	case nil:
 	case wal.ErrSnapshotNotFound:
-		fmt.Printf("Failed to find the match snapshot record %+v in wal %v.", walsnap, srcWAL)
-		fmt.Printf("etcdctl will add it back. Start auto fixing...")
+		log.Printf("Failed to find the match snapshot record %+v in wal %v.", walsnap, srcWAL)
+		log.Printf("etcdctl will add it back. Start auto fixing...")
 	default:
 		log.Fatal(err)
 	}
+
+	re := path.Join(membership.StoreMembersPrefix, "[[:xdigit:]]{1,16}", "attributes")
+	memberAttrRE := regexp.MustCompile(re)
+
+	removed := uint64(0)
+	i := 0
+	remove := func() {
+		ents = append(ents[:i], ents[i+1:]...)
+		removed++
+		i--
+	}
+	for i = 0; i < len(ents); i++ {
+		ents[i].Index -= removed
+		if ents[i].Type == raftpb.EntryConfChange {
+			log.Println("ignoring EntryConfChange raft entry")
+			remove()
+			continue
+		}
+
+		var raftReq etcdserverpb.InternalRaftRequest
+		var v2Req *etcdserverpb.Request
+		if pbutil.MaybeUnmarshal(&raftReq, ents[i].Data) {
+			v2Req = raftReq.V2
+		} else {
+			v2Req = &etcdserverpb.Request{}
+			pbutil.MustUnmarshal(v2Req, ents[i].Data)
+		}
+
+		if v2Req != nil && v2Req.Method == "PUT" && memberAttrRE.MatchString(v2Req.Path) {
+			log.Println("ignoring member attribute update on", v2Req.Path)
+			remove()
+			continue
+		}
+
+		if v2Req != nil {
+			continue
+		}
+
+		if v3 || raftReq.Header == nil {
+			continue
+		}
+		log.Println("ignoring v3 raft entry")
+		remove()
+	}
+	state.Commit -= removed
 	var metadata etcdserverpb.Metadata
 	pbutil.MustUnmarshal(&metadata, wmetadata)
-	idgen := idutil.NewGenerator(0, time.Now())
-	metadata.NodeID = idgen.Next()
-	metadata.ClusterID = idgen.Next()
+	return metadata, state, ents
+}
 
-	neww, err := wal.Create(destWAL, pbutil.MustMarshal(&metadata))
+// saveDB copies the v3 backend and strips cluster information.
+func saveDB(destDB, srcDB string, idx uint64, v3 bool) {
+	// open src db to safely copy db state
+	if v3 {
+		var src *bolt.DB
+		ch := make(chan *bolt.DB, 1)
+		go func() {
+			src, err := bolt.Open(srcDB, 0444, &bolt.Options{ReadOnly: true})
+			if err != nil {
+				log.Fatal(err)
+			}
+			ch <- src
+		}()
+		select {
+		case src = <-ch:
+		case <-time.After(time.Second):
+			log.Println("waiting to acquire lock on", srcDB)
+			src = <-ch
+		}
+		defer src.Close()
+
+		tx, err := src.Begin(false)
+		if err != nil {
+			log.Fatal(err)
+		}
+
+		// copy srcDB to destDB
+		dest, err := os.Create(destDB)
+		if err != nil {
+			log.Fatal(err)
+		}
+		if _, err := tx.WriteTo(dest); err != nil {
+			log.Fatal(err)
+		}
+		dest.Close()
+		if err := tx.Rollback(); err != nil {
+			log.Fatal(err)
+		}
+	}
+
+	db, err := bolt.Open(destDB, 0644, &bolt.Options{})
 	if err != nil {
 		log.Fatal(err)
 	}
-	defer neww.Close()
-	if err := neww.Save(state, ents); err != nil {
+	tx, err := db.Begin(true)
+	if err != nil {
 		log.Fatal(err)
 	}
-	if err := neww.SaveSnapshot(walsnap); err != nil {
-		log.Fatal(err)
+
+	// remove membership information; should be clobbered by --force-new-cluster
+	for _, bucket := range []string{"members", "members_removed", "cluster"} {
+		tx.DeleteBucket([]byte(bucket))
 	}
 
-	return nil
+	// update consistent index to match hard state
+	if !v3 {
+		idxBytes := make([]byte, 8)
+		binary.BigEndian.PutUint64(idxBytes, idx)
+		b, err := tx.CreateBucketIfNotExists([]byte("meta"))
+		if err != nil {
+			log.Fatal(err)
+		}
+		b.Put([]byte("consistent_index"), idxBytes)
+	}
+
+	if err := tx.Commit(); err != nil {
+		log.Fatal(err)
+	}
+	if err := db.Close(); err != nil {
+		log.Fatal(err)
+	}
 }