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Merge pull request #3970 from xiang90/snapshot

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*: rewrite snapshot merging and sending for v3
This commit is contained in:
Xiang Li 2015-12-10 09:55:42 -08:00
commit 9b26753dbf
18 changed files with 308 additions and 763 deletions
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2
etcdserver/config.go
View File

@ -121,8 +121,6 @@ func (c *ServerConfig) WALDir() string {
func (c *ServerConfig) SnapDir() string { return path.Join(c.MemberDir(), "snap") }
func (c *ServerConfig) StorageDir() string { return path.Join(c.MemberDir(), "storage") }
func (c *ServerConfig) ShouldDiscover() bool { return c.DiscoveryURL != "" }
// ReqTimeout returns timeout for request to finish.

15
etcdserver/raft.go
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@ -109,7 +109,7 @@ type raftNode struct {
// utility
ticker <-chan time.Time
raftStorage *raftStorage
raftStorage *raft.MemoryStorage
storage Storage
// transport specifies the transport to send and receive msgs to members.
// Sending messages MUST NOT block. It is okay to drop messages, since
@ -126,7 +126,6 @@ type raftNode struct {
// TODO: Ideally raftNode should get rid of the passed in server structure.
func (r *raftNode) start(s *EtcdServer) {
r.s = s
r.raftStorage.raftStarted = true
r.applyc = make(chan apply)
r.stopped = make(chan struct{})
r.done = make(chan struct{})
@ -245,7 +244,7 @@ func advanceTicksForElection(n raft.Node, electionTicks int) {
}
}
func startNode(cfg *ServerConfig, cl *cluster, ids []types.ID) (id types.ID, n raft.Node, s *raftStorage, w *wal.WAL) {
func startNode(cfg *ServerConfig, cl *cluster, ids []types.ID) (id types.ID, n raft.Node, s *raft.MemoryStorage, w *wal.WAL) {
var err error
member := cl.MemberByName(cfg.Name)
metadata := pbutil.MustMarshal(
@ -270,7 +269,7 @@ func startNode(cfg *ServerConfig, cl *cluster, ids []types.ID) (id types.ID, n r
}
id = member.ID
plog.Infof("starting member %s in cluster %s", id, cl.ID())
s = newRaftStorage()
s = raft.NewMemoryStorage()
c := &raft.Config{
ID: uint64(id),
ElectionTick: cfg.ElectionTicks,
@ -287,7 +286,7 @@ func startNode(cfg *ServerConfig, cl *cluster, ids []types.ID) (id types.ID, n r
return
}
func restartNode(cfg *ServerConfig, snapshot *raftpb.Snapshot) (types.ID, *cluster, raft.Node, *raftStorage, *wal.WAL) {
func restartNode(cfg *ServerConfig, snapshot *raftpb.Snapshot) (types.ID, *cluster, raft.Node, *raft.MemoryStorage, *wal.WAL) {
var walsnap walpb.Snapshot
if snapshot != nil {
walsnap.Index, walsnap.Term = snapshot.Metadata.Index, snapshot.Metadata.Term
@ -297,7 +296,7 @@ func restartNode(cfg *ServerConfig, snapshot *raftpb.Snapshot) (types.ID, *clust
plog.Infof("restarting member %s in cluster %s at commit index %d", id, cid, st.Commit)
cl := newCluster("")
cl.SetID(cid)
s := newRaftStorage()
s := raft.NewMemoryStorage()
if snapshot != nil {
s.ApplySnapshot(*snapshot)
}
@ -319,7 +318,7 @@ func restartNode(cfg *ServerConfig, snapshot *raftpb.Snapshot) (types.ID, *clust
return id, cl, n, s, w
}
func restartAsStandaloneNode(cfg *ServerConfig, snapshot *raftpb.Snapshot) (types.ID, *cluster, raft.Node, *raftStorage, *wal.WAL) {
func restartAsStandaloneNode(cfg *ServerConfig, snapshot *raftpb.Snapshot) (types.ID, *cluster, raft.Node, *raft.MemoryStorage, *wal.WAL) {
var walsnap walpb.Snapshot
if snapshot != nil {
walsnap.Index, walsnap.Term = snapshot.Metadata.Index, snapshot.Metadata.Term
@ -351,7 +350,7 @@ func restartAsStandaloneNode(cfg *ServerConfig, snapshot *raftpb.Snapshot) (type
plog.Printf("forcing restart of member %s in cluster %s at commit index %d", id, cid, st.Commit)
cl := newCluster("")
cl.SetID(cid)
s := newRaftStorage()
s := raft.NewMemoryStorage()
if snapshot != nil {
s.ApplySnapshot(*snapshot)
}

64
etcdserver/raft_storage.go
View File

@ -1,64 +0,0 @@
// 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 etcdserver
import (
"github.com/coreos/etcd/raft"
"github.com/coreos/etcd/raft/raftpb"
)
type raftStorage struct {
*raft.MemoryStorage
// snapStore is the place to request snapshot when v3demo is enabled.
// If snapStore is nil, it uses the snapshot saved in MemoryStorage.
snapStore *snapshotStore
// raftStarted indicates whether raft starts to function. If not, it cannot
// request snapshot, and should get snapshot from MemoryStorage.
raftStarted bool
}
func newRaftStorage() *raftStorage {
return &raftStorage{
MemoryStorage: raft.NewMemoryStorage(),
}
}
func (rs *raftStorage) reqsnap() <-chan struct{} {
if rs.snapStore == nil {
return nil
}
return rs.snapStore.reqsnapc
}
func (rs *raftStorage) raftsnap() chan<- raftpb.Snapshot {
if rs.snapStore == nil {
return nil
}
return rs.snapStore.raftsnapc
}
// Snapshot returns raft snapshot. If snapStore is nil or raft is not started, this method
// returns snapshot saved in MemoryStorage. Otherwise, this method
// returns snapshot from snapStore.
func (rs *raftStorage) Snapshot() (raftpb.Snapshot, error) {
if rs.snapStore == nil || !rs.raftStarted {
return rs.MemoryStorage.Snapshot()
}
snap, err := rs.snapStore.getSnap()
if err != nil {
return raftpb.Snapshot{}, err
}
return snap.raft(), nil
}

2
etcdserver/raft_test.go
View File

@ -153,7 +153,7 @@ func TestStopRaftWhenWaitingForApplyDone(t *testing.T) {
r := raftNode{
Node: n,
storage: &storageRecorder{},
raftStorage: newRaftStorage(),
raftStorage: raft.NewMemoryStorage(),
transport: &nopTransporter{},
}
r.start(&EtcdServer{r: r})

93
etcdserver/server.go
View File

@ -19,7 +19,6 @@ import (
"errors"
"expvar"
"fmt"
"log"
"math/rand"
"net/http"
"os"
@ -65,6 +64,9 @@ const (
monitorVersionInterval = 5 * time.Second
databaseFilename = "db"
// max number of in-flight snapshot messages etcdserver allows to have
// This number is more than enough for most clusters with 5 machines.
maxInFlightMsgSnap = 16
)
var (
@ -177,19 +179,23 @@ type EtcdServer struct {
// forceVersionC is used to force the version monitor loop
// to detect the cluster version immediately.
forceVersionC chan struct{}
msgSnapC chan raftpb.Message
}
// NewServer creates a new EtcdServer from the supplied configuration. The
// configuration is considered static for the lifetime of the EtcdServer.
func NewServer(cfg *ServerConfig) (*EtcdServer, error) {
st := store.New(StoreClusterPrefix, StoreKeysPrefix)
var w *wal.WAL
var n raft.Node
var s *raftStorage
var id types.ID
var cl *cluster
var (
w *wal.WAL
n raft.Node
s *raft.MemoryStorage
id types.ID
cl *cluster
)
if !cfg.V3demo && fileutil.Exist(path.Join(cfg.StorageDir(), databaseFilename)) {
if !cfg.V3demo && fileutil.Exist(path.Join(cfg.SnapDir(), databaseFilename)) {
return nil, errors.New("experimental-v3demo cannot be disabled once it is enabled")
}
@ -340,18 +346,14 @@ func NewServer(cfg *ServerConfig) (*EtcdServer, error) {
versionRt: prt,
reqIDGen: idutil.NewGenerator(uint8(id), time.Now()),
forceVersionC: make(chan struct{}),
msgSnapC: make(chan raftpb.Message, maxInFlightMsgSnap),
}
if cfg.V3demo {
err = os.MkdirAll(cfg.StorageDir(), privateDirMode)
if err != nil && err != os.ErrExist {
return nil, err
}
srv.kv = dstorage.New(path.Join(cfg.StorageDir(), databaseFilename), &srv.consistIndex)
srv.kv = dstorage.New(path.Join(cfg.SnapDir(), databaseFilename), &srv.consistIndex)
if err := srv.kv.Restore(); err != nil {
plog.Fatalf("v3 storage restore error: %v", err)
}
s.snapStore = newSnapshotStore(cfg.StorageDir(), srv.kv)
}
// TODO: move transport initialization near the definition of remote
@ -361,7 +363,7 @@ func NewServer(cfg *ServerConfig) (*EtcdServer, error) {
ID: id,
ClusterID: cl.ID(),
Raft: srv,
SnapSaver: s.snapStore,
Snapshotter: ss,
ServerStats: sstats,
LeaderStats: lstats,
ErrorC: srv.errorc,
@ -383,10 +385,6 @@ func NewServer(cfg *ServerConfig) (*EtcdServer, error) {
}
srv.r.transport = tr
if cfg.V3demo {
s.snapStore.tr = tr
}
return srv, nil
}
@ -465,9 +463,6 @@ func (s *EtcdServer) ReportUnreachable(id uint64) { s.r.ReportUnreachable(id) }
// and clears the used snapshot from the snapshot store.
func (s *EtcdServer) ReportSnapshot(id uint64, status raft.SnapshotStatus) {
s.r.ReportSnapshot(id, status)
if s.cfg.V3demo {
s.r.raftStorage.snapStore.clearUsedSnap()
}
}
func (s *EtcdServer) run() {
@ -496,12 +491,12 @@ func (s *EtcdServer) run() {
}
if s.cfg.V3demo {
snapfn, err := s.r.raftStorage.snapStore.getSnapFilePath(apply.snapshot.Metadata.Index)
snapfn, err := s.r.storage.DBFilePath(apply.snapshot.Metadata.Index)
if err != nil {
plog.Panicf("get snapshot file path error: %v", err)
plog.Panicf("get database snapshot file path error: %v", err)
}
fn := path.Join(s.cfg.StorageDir(), databaseFilename)
fn := path.Join(s.cfg.SnapDir(), databaseFilename)
if err := os.Rename(snapfn, fn); err != nil {
plog.Panicf("rename snapshot file error: %v", err)
}
@ -514,7 +509,6 @@ func (s *EtcdServer) run() {
oldKV := s.kv
// TODO: swap the kv pointer atomically
s.kv = newKV
s.r.raftStorage.snapStore.kv = newKV
// Closing oldKV might block until all the txns
// on the kv are finished.
@ -571,9 +565,9 @@ func (s *EtcdServer) run() {
s.snapshot(appliedi, confState)
snapi = appliedi
}
case <-s.r.raftStorage.reqsnap():
s.r.raftStorage.raftsnap() <- s.createRaftSnapshot(appliedi, confState)
plog.Infof("requested snapshot created at %d", appliedi)
case m := <-s.msgSnapC:
merged := s.createMergedSnapshotMessage(m, appliedi, confState)
s.r.transport.SendSnapshot(merged)
case err := <-s.errorc:
plog.Errorf("%s", err)
plog.Infof("the data-dir used by this member must be removed.")
@ -828,7 +822,24 @@ func (s *EtcdServer) send(ms []raftpb.Message) {
if s.cluster.IsIDRemoved(types.ID(ms[i].To)) {
ms[i].To = 0
}
if s.cfg.V3demo {
if ms[i].Type == raftpb.MsgSnap {
// There are two separate data store when v3 demo is enabled: the store for v2,
// and the KV for v3.
// The msgSnap only contains the most recent snapshot of store without KV.
// So we need to redirect the msgSnap to etcd server main loop for merging in the
// current store snapshot and KV snapshot.
select {
case s.msgSnapC <- ms[i]:
default:
// drop msgSnap if the inflight chan if full.
}
ms[i].To = 0
}
}
}
s.r.transport.Send(ms)
}
@ -998,29 +1009,6 @@ func (s *EtcdServer) applyConfChange(cc raftpb.ConfChange, confState *raftpb.Con
return false, nil
}
// createRaftSnapshot creates a raft snapshot that includes the state of store for v2 api.
func (s *EtcdServer) createRaftSnapshot(snapi uint64, confState raftpb.ConfState) raftpb.Snapshot {
snapt, err := s.r.raftStorage.Term(snapi)
if err != nil {
log.Panicf("get term should never fail: %v", err)
}
clone := s.store.Clone()
d, err := clone.SaveNoCopy()
if err != nil {
plog.Panicf("store save should never fail: %v", err)
}
return raftpb.Snapshot{
Metadata: raftpb.SnapshotMetadata{
Index: snapi,
Term: snapt,
ConfState: confState,
},
Data: d,
}
}
// TODO: non-blocking snapshot
func (s *EtcdServer) snapshot(snapi uint64, confState raftpb.ConfState) {
clone := s.store.Clone()
@ -1068,9 +1056,6 @@ func (s *EtcdServer) snapshot(snapi uint64, confState raftpb.ConfState) {
plog.Panicf("unexpected compaction error %v", err)
}
plog.Infof("compacted raft log at %d", compacti)
if s.cfg.V3demo && s.r.raftStorage.snapStore.closeSnapBefore(compacti) {
plog.Infof("closed snapshot stored due to compaction at %d", compacti)
}
}()
}

95
etcdserver/server_test.go
View File

@ -17,7 +17,6 @@ package etcdserver
import (
"encoding/json"
"fmt"
"io"
"net/http"
"path"
"reflect"
@ -33,6 +32,7 @@ import (
"github.com/coreos/etcd/pkg/types"
"github.com/coreos/etcd/raft"
"github.com/coreos/etcd/raft/raftpb"
"github.com/coreos/etcd/snap"
"github.com/coreos/etcd/store"
)
@ -523,7 +523,7 @@ func TestDoProposal(t *testing.T) {
r: raftNode{
Node: newNodeCommitter(),
storage: &storageRecorder{},
raftStorage: newRaftStorage(),
raftStorage: raft.NewMemoryStorage(),
transport: &nopTransporter{},
},
store: st,
@ -675,7 +675,7 @@ func TestSyncTrigger(t *testing.T) {
cfg: &ServerConfig{TickMs: 1},
r: raftNode{
Node: n,
raftStorage: newRaftStorage(),
raftStorage: raft.NewMemoryStorage(),
transport: &nopTransporter{},
storage: &storageRecorder{},
},
@ -712,51 +712,9 @@ func TestSyncTrigger(t *testing.T) {
}
}
func TestCreateRaftSnapshot(t *testing.T) {
s := newRaftStorage()
s.Append([]raftpb.Entry{{Index: 1, Term: 1}})
st := &storeRecorder{}
srv := &EtcdServer{
r: raftNode{
raftStorage: s,
},
store: st,
}
snap := srv.createRaftSnapshot(1, raftpb.ConfState{Nodes: []uint64{1}})
wdata, err := st.Save()
if err != nil {
t.Fatal(err)
}
wsnap := raftpb.Snapshot{
Metadata: raftpb.SnapshotMetadata{
Index: 1,
Term: 1,
ConfState: raftpb.ConfState{Nodes: []uint64{1}},
},
Data: wdata,
}
if !reflect.DeepEqual(snap, wsnap) {
t.Errorf("snap = %+v, want %+v", snap, wsnap)
}
gaction := st.Action()
// the third action is store.Save used in testing
if len(gaction) != 3 {
t.Fatalf("len(action) = %d, want 3", len(gaction))
}
if !reflect.DeepEqual(gaction[0], testutil.Action{Name: "Clone"}) {
t.Errorf("action = %s, want Clone", gaction[0])
}
if !reflect.DeepEqual(gaction[1], testutil.Action{Name: "SaveNoCopy"}) {
t.Errorf("action = %s, want SaveNoCopy", gaction[1])
}
}
// snapshot should snapshot the store and cut the persistent
func TestSnapshot(t *testing.T) {
s := newRaftStorage()
s := raft.NewMemoryStorage()
s.Append([]raftpb.Entry{{Index: 1}})
st := &storeRecorder{}
p := &storageRecorder{}
@ -800,7 +758,7 @@ func TestTriggerSnap(t *testing.T) {
snapCount: uint64(snapc),
r: raftNode{
Node: newNodeCommitter(),
raftStorage: newRaftStorage(),
raftStorage: raft.NewMemoryStorage(),
storage: p,
transport: &nopTransporter{},
},
@ -841,7 +799,7 @@ func TestRecvSnapshot(t *testing.T) {
Node: n,
transport: &nopTransporter{},
storage: p,
raftStorage: newRaftStorage(),
raftStorage: raft.NewMemoryStorage(),
},
store: st,
cluster: cl,
@ -874,7 +832,7 @@ func TestApplySnapshotAndCommittedEntries(t *testing.T) {
st := &storeRecorder{}
cl := newCluster("abc")
cl.SetStore(store.New())
storage := newRaftStorage()
storage := raft.NewMemoryStorage()
s := &EtcdServer{
cfg: &ServerConfig{},
r: raftNode{
@ -923,7 +881,7 @@ func TestAddMember(t *testing.T) {
s := &EtcdServer{
r: raftNode{
Node: n,
raftStorage: newRaftStorage(),
raftStorage: raft.NewMemoryStorage(),
storage: &storageRecorder{},
transport: &nopTransporter{},
},
@ -963,7 +921,7 @@ func TestRemoveMember(t *testing.T) {
s := &EtcdServer{
r: raftNode{
Node: n,
raftStorage: newRaftStorage(),
raftStorage: raft.NewMemoryStorage(),
storage: &storageRecorder{},
transport: &nopTransporter{},
},
@ -1002,7 +960,7 @@ func TestUpdateMember(t *testing.T) {
s := &EtcdServer{
r: raftNode{
Node: n,
raftStorage: newRaftStorage(),
raftStorage: raft.NewMemoryStorage(),
storage: &storageRecorder{},
transport: &nopTransporter{},
},
@ -1355,12 +1313,19 @@ func (p *storageRecorder) Save(st raftpb.HardState, ents []raftpb.Entry) error {
p.Record(testutil.Action{Name: "Save"})
return nil
}
func (p *storageRecorder) SaveSnap(st raftpb.Snapshot) error {
if !raft.IsEmptySnap(st) {
p.Record(testutil.Action{Name: "SaveSnap"})
}
return nil
}
func (p *storageRecorder) DBFilePath(id uint64) (string, error) {
p.Record(testutil.Action{Name: "DBFilePath"})
return fmt.Sprintf("%016x.snap.db", id), nil
}
func (p *storageRecorder) Close() error { return nil }
type nodeRecorder struct{ testutil.Recorder }
@ -1477,16 +1442,16 @@ func (n *readyNode) Ready() <-chan raft.Ready { return n.readyc }
type nopTransporter struct{}
func (s *nopTransporter) Start() error { return nil }
func (s *nopTransporter) Handler() http.Handler { return nil }
func (s *nopTransporter) Send(m []raftpb.Message) {}
func (s *nopTransporter) AddRemote(id types.ID, us []string) {}
func (s *nopTransporter) AddPeer(id types.ID, us []string) {}
func (s *nopTransporter) RemovePeer(id types.ID) {}
func (s *nopTransporter) RemoveAllPeers() {}
func (s *nopTransporter) UpdatePeer(id types.ID, us []string) {}
func (s *nopTransporter) ActiveSince(id types.ID) time.Time { return time.Time{} }
func (s *nopTransporter) SnapshotReady(rc io.ReadCloser, index uint64) {}
func (s *nopTransporter) Stop() {}
func (s *nopTransporter) Pause() {}
func (s *nopTransporter) Resume() {}
func (s *nopTransporter) Start() error { return nil }
func (s *nopTransporter) Handler() http.Handler { return nil }
func (s *nopTransporter) Send(m []raftpb.Message) {}
func (s *nopTransporter) SendSnapshot(m snap.Message) {}
func (s *nopTransporter) AddRemote(id types.ID, us []string) {}
func (s *nopTransporter) AddPeer(id types.ID, us []string) {}
func (s *nopTransporter) RemovePeer(id types.ID) {}
func (s *nopTransporter) RemoveAllPeers() {}
func (s *nopTransporter) UpdatePeer(id types.ID, us []string) {}
func (s *nopTransporter) ActiveSince(id types.ID) time.Time { return time.Time{} }
func (s *nopTransporter) Stop() {}
func (s *nopTransporter) Pause() {}
func (s *nopTransporter) Resume() {}

71
etcdserver/snapshot_merge.go Normal file
View File

@ -0,0 +1,71 @@
// 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 etcdserver
import (
"io"
"log"
"github.com/coreos/etcd/raft/raftpb"
"github.com/coreos/etcd/snap"
dstorage "github.com/coreos/etcd/storage"
)
// createMergedSnapshotMessage creates a snapshot message that contains: raft status (term, conf),
// a snapshot of v2 store inside raft.Snapshot as []byte, a snapshot of v3 KV in the top level message
// as ReadCloser.
func (s *EtcdServer) createMergedSnapshotMessage(m raftpb.Message, snapi uint64, confState raftpb.ConfState) snap.Message {
snapt, err := s.r.raftStorage.Term(snapi)
if err != nil {
log.Panicf("get term should never fail: %v", err)
}
// get a snapshot of v2 store as []byte
clone := s.store.Clone()
d, err := clone.SaveNoCopy()
if err != nil {
plog.Panicf("store save should never fail: %v", err)
}
// get a snapshot of v3 KV as readCloser
rc := newSnapshotReaderCloser(s.kv.Snapshot())
// put the []byte snapshot of store into raft snapshot and return the merged snapshot with
// KV readCloser snapshot.
snapshot := raftpb.Snapshot{
Metadata: raftpb.SnapshotMetadata{
Index: snapi,
Term: snapt,
ConfState: confState,
},
Data: d,
}
m.Snapshot = snapshot
return snap.Message{
Message: m,
ReadCloser: rc,
}
}
func newSnapshotReaderCloser(snapshot dstorage.Snapshot) io.ReadCloser {
pr, pw := io.Pipe()
go func() {
_, err := snapshot.WriteTo(pw)
pw.CloseWithError(err)
snapshot.Close()
}()
return pr
}

260
etcdserver/snapshot_store.go
View File

@ -1,260 +0,0 @@
// 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 etcdserver
import (
"fmt"
"io"
"io/ioutil"
"os"
"path"
"sync"
"time"
"github.com/coreos/etcd/Godeps/_workspace/src/github.com/jonboulle/clockwork"
"github.com/coreos/etcd/pkg/fileutil"
"github.com/coreos/etcd/raft"
"github.com/coreos/etcd/raft/raftpb"
"github.com/coreos/etcd/rafthttp"
dstorage "github.com/coreos/etcd/storage"
)
// clearUnusedSnapshotInterval specifies the time interval to wait
// before clearing unused snapshot.
// The newly created snapshot should be retrieved within one heartbeat
// interval because raft state machine retries to send snapshot
// to slow follower when receiving MsgHeartbeatResp from the follower.
// Set it as 5s to match the upper limit of heartbeat interval.
const clearUnusedSnapshotInterval = 5 * time.Second
type snapshot struct {
r raftpb.Snapshot
io.ReadCloser // used to read out v3 snapshot
done chan struct{}
}
func newSnapshot(r raftpb.Snapshot, kv dstorage.Snapshot) *snapshot {
done := make(chan struct{})
pr, pw := io.Pipe()
go func() {
_, err := kv.WriteTo(pw)
pw.CloseWithError(err)
kv.Close()
close(done)
}()
return &snapshot{
r: r,
ReadCloser: pr,
done: done,
}
}
func (s *snapshot) raft() raftpb.Snapshot { return s.r }
func (s *snapshot) isClosed() bool {
select {
case <-s.done:
return true
default:
return false
}
}
// TODO: remove snapshotStore. getSnap part could be put into memoryStorage,
// while SaveFrom could be put into another struct, or even put into dstorage package.
type snapshotStore struct {
// dir to save snapshot data
dir string
kv dstorage.KV
tr rafthttp.Transporter
// send empty to reqsnapc to notify the channel receiver to send back latest
// snapshot to snapc
reqsnapc chan struct{}
// a chan to receive the requested raft snapshot
// snapshotStore will receive from the chan immediately after it sends empty to reqsnapc
raftsnapc chan raftpb.Snapshot
mu sync.Mutex // protect belowing vars
// snap is nil iff there is no snapshot stored
snap *snapshot
inUse bool
createOnce sync.Once // ensure at most one snapshot is created when no snapshot stored
clock clockwork.Clock
}
func newSnapshotStore(dir string, kv dstorage.KV) *snapshotStore {
return &snapshotStore{
dir: dir,
kv: kv,
reqsnapc: make(chan struct{}),
raftsnapc: make(chan raftpb.Snapshot),
clock: clockwork.NewRealClock(),
}
}
// getSnap returns a snapshot.
// If there is no available snapshot, ErrSnapshotTemporarilyUnavaliable will be returned.
//
// If the snapshot stored is in use, it returns ErrSnapshotTemporarilyUnavailable.
// If there is no snapshot stored, it creates new snapshot
// asynchronously and returns ErrSnapshotTemporarilyUnavailable, so
// caller could get snapshot later when the snapshot is created.
// Otherwise, it returns the snapshot stored.
//
// The created snapshot is cleared from the snapshot store if it is
// either unused after clearUnusedSnapshotInterval, or explicitly cleared
// through clearUsedSnap after using.
// closeSnapBefore is used to close outdated snapshot,
// so the snapshot will be cleared faster when in use.
//
// snapshot store stores at most one snapshot at a time.
// If raft state machine wants to send two snapshot messages to two followers,
// the second snapshot message will keep getting snapshot and succeed only after
// the first message is sent. This increases the time used to send messages,
// but it is acceptable because this should happen seldomly.
func (ss *snapshotStore) getSnap() (*snapshot, error) {
ss.mu.Lock()
defer ss.mu.Unlock()
if ss.inUse {
return nil, raft.ErrSnapshotTemporarilyUnavailable
}
if ss.snap == nil {
// create snapshot asynchronously
ss.createOnce.Do(func() { go ss.createSnap() })
return nil, raft.ErrSnapshotTemporarilyUnavailable
}
ss.inUse = true
// give transporter the generated snapshot that is ready to send out
ss.tr.SnapshotReady(ss.snap, ss.snap.raft().Metadata.Index)
return ss.snap, nil
}
// clearUsedSnap clears the snapshot from the snapshot store after it
// is used.
// After clear, snapshotStore could create new snapshot when getSnap.
func (ss *snapshotStore) clearUsedSnap() {
ss.mu.Lock()
defer ss.mu.Unlock()
if !ss.inUse {
plog.Panicf("unexpected clearUsedSnap when snapshot is not in use")
}
ss.clear()
}
// closeSnapBefore closes the stored snapshot if its index is not greater
// than the given compact index.
// If it closes the snapshot, it returns true.
func (ss *snapshotStore) closeSnapBefore(index uint64) bool {
ss.mu.Lock()
defer ss.mu.Unlock()
if ss.snap != nil && ss.snap.raft().Metadata.Index <= index {
if err := ss.snap.Close(); err != nil {
plog.Errorf("snapshot close error (%v)", err)
}
return true
}
return false
}
// createSnap creates a new snapshot and stores it into the snapshot store.
// It also sets a timer to clear the snapshot if it is not in use after
// some time interval.
// It should only be called in snapshotStore functions.
func (ss *snapshotStore) createSnap() {
// ask to generate v2 snapshot
ss.reqsnapc <- struct{}{}
// generate KV snapshot
kvsnap := ss.kv.Snapshot()
raftsnap := <-ss.raftsnapc
snap := newSnapshot(raftsnap, kvsnap)
ss.mu.Lock()
ss.snap = snap
ss.mu.Unlock()
go func() {
<-ss.clock.After(clearUnusedSnapshotInterval)
ss.mu.Lock()
defer ss.mu.Unlock()
if snap == ss.snap && !ss.inUse {
ss.clear()
}
}()
}
// clear clears snapshot related variables in snapshotStore. It closes
// the snapshot stored and sets the variables to initial values.
// It should only be called in snapshotStore functions.
func (ss *snapshotStore) clear() {
if err := ss.snap.Close(); err != nil {
plog.Errorf("snapshot close error (%v)", err)
}
ss.snap = nil
ss.inUse = false
ss.createOnce = sync.Once{}
}
// SaveFrom saves snapshot at the given index from the given reader.
// If the snapshot with the given index has been saved successfully, it keeps
// the original saved snapshot and returns error.
// The function guarantees that SaveFrom always saves either complete
// snapshot or no snapshot, even if the call is aborted because program
// is hard killed.
func (ss *snapshotStore) SaveFrom(r io.Reader, index uint64) error {
f, err := ioutil.TempFile(ss.dir, "tmp")
if err != nil {
return err
}
_, err = io.Copy(f, r)
f.Close()
if err != nil {
os.Remove(f.Name())
return err
}
fn := path.Join(ss.dir, fmt.Sprintf("%016x.db", index))
if fileutil.Exist(fn) {
os.Remove(f.Name())
return fmt.Errorf("snapshot to save has existed")
}
err = os.Rename(f.Name(), fn)
if err != nil {
os.Remove(f.Name())
return err
}
return nil
}
// getSnapFilePath returns the file path for the snapshot with given index.
// If the snapshot does not exist, it returns error.
func (ss *snapshotStore) getSnapFilePath(index uint64) (string, error) {
fns, err := fileutil.ReadDir(ss.dir)
if err != nil {
return "", err
}
wfn := fmt.Sprintf("%016x.db", index)
for _, fn := range fns {
if fn == wfn {
return path.Join(ss.dir, fn), nil
}
}
return "", fmt.Errorf("snapshot file doesn't exist")
}

205
etcdserver/snapshot_store_test.go
View File

@ -1,205 +0,0 @@
// 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 etcdserver
import (
"io"
"reflect"
"sync"
"testing"
"github.com/coreos/etcd/Godeps/_workspace/src/github.com/jonboulle/clockwork"
"github.com/coreos/etcd/pkg/testutil"
"github.com/coreos/etcd/raft"
"github.com/coreos/etcd/raft/raftpb"
dstorage "github.com/coreos/etcd/storage"
"github.com/coreos/etcd/storage/storagepb"
)
func TestSnapshotStoreCreateSnap(t *testing.T) {
snap := raftpb.Snapshot{
Metadata: raftpb.SnapshotMetadata{Index: 1},
}
ss := newSnapshotStore("", &nopKV{})
fakeClock := clockwork.NewFakeClock()
ss.clock = fakeClock
go func() {
<-ss.reqsnapc
ss.raftsnapc <- snap
}()
// create snapshot
ss.createSnap()
if !reflect.DeepEqual(ss.snap.raft(), snap) {
t.Errorf("raftsnap = %+v, want %+v", ss.snap.raft(), snap)
}
// unused snapshot is cleared after clearUnusedSnapshotInterval
fakeClock.BlockUntil(1)
fakeClock.Advance(clearUnusedSnapshotInterval)
testutil.WaitSchedule()
ss.mu.Lock()
if ss.snap != nil {
t.Errorf("snap = %+v, want %+v", ss.snap, nil)
}
ss.mu.Unlock()
}
func TestSnapshotStoreGetSnap(t *testing.T) {
snap := raftpb.Snapshot{
Metadata: raftpb.SnapshotMetadata{Index: 1},
}
ss := newSnapshotStore("", &nopKV{})
fakeClock := clockwork.NewFakeClock()
ss.clock = fakeClock
ss.tr = &nopTransporter{}
go func() {
<-ss.reqsnapc
ss.raftsnapc <- snap
}()
// get snap when no snapshot stored
_, err := ss.getSnap()
if err != raft.ErrSnapshotTemporarilyUnavailable {
t.Fatalf("getSnap error = %v, want %v", err, raft.ErrSnapshotTemporarilyUnavailable)
}
// wait for asynchronous snapshot creation to finish
testutil.WaitSchedule()
// get the created snapshot
s, err := ss.getSnap()
if err != nil {
t.Fatalf("getSnap error = %v, want nil", err)
}
if !reflect.DeepEqual(s.raft(), snap) {
t.Errorf("raftsnap = %+v, want %+v", s.raft(), snap)
}
if !ss.inUse {
t.Errorf("inUse = %v, want true", ss.inUse)
}
// get snap when snapshot stored has been in use
_, err = ss.getSnap()
if err != raft.ErrSnapshotTemporarilyUnavailable {
t.Fatalf("getSnap error = %v, want %v", err, raft.ErrSnapshotTemporarilyUnavailable)
}
// clean up
fakeClock.Advance(clearUnusedSnapshotInterval)
}
func TestSnapshotStoreClearUsedSnap(t *testing.T) {
s := &fakeSnapshot{}
var once sync.Once
once.Do(func() {})
ss := &snapshotStore{
snap: newSnapshot(raftpb.Snapshot{}, s),
inUse: true,
createOnce: once,
}
ss.clearUsedSnap()
// wait for underlying KV snapshot closed
testutil.WaitSchedule()
s.mu.Lock()
if !s.closed {
t.Errorf("snapshot closed = %v, want true", s.closed)
}
s.mu.Unlock()
if ss.snap != nil {
t.Errorf("snapshot = %v, want nil", ss.snap)
}
if ss.inUse {
t.Errorf("isUse = %v, want false", ss.inUse)
}
// test createOnce is reset
if ss.createOnce == once {
t.Errorf("createOnce fails to reset")
}
}
func TestSnapshotStoreCloseSnapBefore(t *testing.T) {
snapIndex := uint64(5)
tests := []struct {
index uint64
wok bool
}{
{snapIndex - 2, false},
{snapIndex - 1, false},
{snapIndex, true},
}
for i, tt := range tests {
rs := raftpb.Snapshot{
Metadata: raftpb.SnapshotMetadata{Index: 5},
}
s := &fakeSnapshot{}
ss := &snapshotStore{
snap: newSnapshot(rs, s),
}
ok := ss.closeSnapBefore(tt.index)
if ok != tt.wok {
t.Errorf("#%d: closeSnapBefore = %v, want %v", i, ok, tt.wok)
}
if ok {
// wait for underlying KV snapshot closed
testutil.WaitSchedule()
s.mu.Lock()
if !s.closed {
t.Errorf("#%d: snapshot closed = %v, want true", i, s.closed)
}
s.mu.Unlock()
}
}
}
type nopKV struct{}
func (kv *nopKV) Rev() int64 { return 0 }
func (kv *nopKV) Range(key, end []byte, limit, rangeRev int64) (kvs []storagepb.KeyValue, rev int64, err error) {
return nil, 0, nil
}
func (kv *nopKV) Put(key, value []byte) (rev int64) { return 0 }
func (kv *nopKV) DeleteRange(key, end []byte) (n, rev int64) { return 0, 0 }
func (kv *nopKV) TxnBegin() int64 { return 0 }
func (kv *nopKV) TxnEnd(txnID int64) error { return nil }
func (kv *nopKV) TxnRange(txnID int64, key, end []byte, limit, rangeRev int64) (kvs []storagepb.KeyValue, rev int64, err error) {
return nil, 0, nil
}
func (kv *nopKV) TxnPut(txnID int64, key, value []byte) (rev int64, err error) { return 0, nil }
func (kv *nopKV) TxnDeleteRange(txnID int64, key, end []byte) (n, rev int64, err error) {
return 0, 0, nil
}
func (kv *nopKV) Compact(rev int64) error { return nil }
func (kv *nopKV) Hash() (uint32, error) { return 0, nil }
func (kv *nopKV) Snapshot() dstorage.Snapshot { return &fakeSnapshot{} }
func (kv *nopKV) Commit() {}
func (kv *nopKV) Restore() error { return nil }
func (kv *nopKV) Close() error { return nil }
type fakeSnapshot struct {
mu sync.Mutex
closed bool
}
func (s *fakeSnapshot) Size() int64 { return 0 }
func (s *fakeSnapshot) WriteTo(w io.Writer) (int64, error) { return 0, nil }
func (s *fakeSnapshot) Close() error {
s.mu.Lock()
s.closed = true
s.mu.Unlock()
return nil
}

3
etcdserver/storage.go
View File

@ -35,6 +35,9 @@ type Storage interface {
Save(st raftpb.HardState, ents []raftpb.Entry) error
// SaveSnap function saves snapshot to the underlying stable storage.
SaveSnap(snap raftpb.Snapshot) error
// DBFilePath returns the file path of database snapshot saved with given
// id.
DBFilePath(id uint64) (string, error)
// Close closes the Storage and performs finalization.
Close() error
}

21
rafthttp/http.go
View File

@ -25,6 +25,7 @@ import (
pioutil "github.com/coreos/etcd/pkg/ioutil"
"github.com/coreos/etcd/pkg/types"
"github.com/coreos/etcd/raft/raftpb"
"github.com/coreos/etcd/snap"
"github.com/coreos/etcd/version"
)
@ -118,16 +119,16 @@ func (h *pipelineHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
}
type snapshotHandler struct {
r Raft
snapSaver SnapshotSaver
cid types.ID
r Raft
snapshotter *snap.Snapshotter
cid types.ID
}
func newSnapshotHandler(r Raft, snapSaver SnapshotSaver, cid types.ID) http.Handler {
func newSnapshotHandler(r Raft, snapshotter *snap.Snapshotter, cid types.ID) http.Handler {
return &snapshotHandler{
r: r,
snapSaver: snapSaver,
cid: cid,
r: r,
snapshotter: snapshotter,
cid: cid,
}
}
@ -168,14 +169,14 @@ func (h *snapshotHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
return
}
// save snapshot
if err := h.snapSaver.SaveFrom(r.Body, m.Snapshot.Metadata.Index); err != nil {
// save incoming database snapshot.
if err := h.snapshotter.SaveDBFrom(r.Body, m.Snapshot.Metadata.Index); err != nil {
msg := fmt.Sprintf("failed to save KV snapshot (%v)", err)
plog.Error(msg)
http.Error(w, msg, http.StatusInternalServerError)
return
}
plog.Infof("received and saved snapshot [index: %d, from: %s] successfully", m.Snapshot.Metadata.Index, types.ID(m.From))
plog.Infof("received and saved database snapshot [index: %d, from: %s] successfully", m.Snapshot.Metadata.Index, types.ID(m.From))
if err := h.r.Process(context.TODO(), m); err != nil {
switch v := err.(type) {

9
rafthttp/http_test.go
View File

@ -28,6 +28,7 @@ import (
"github.com/coreos/etcd/pkg/pbutil"
"github.com/coreos/etcd/pkg/types"
"github.com/coreos/etcd/raft/raftpb"
"github.com/coreos/etcd/snap"
"github.com/coreos/etcd/version"
)
@ -340,9 +341,10 @@ type fakePeerGetter struct {
func (pg *fakePeerGetter) Get(id types.ID) Peer { return pg.peers[id] }
type fakePeer struct {
msgs []raftpb.Message
urls types.URLs
connc chan *outgoingConn
msgs []raftpb.Message
snapMsgs []snap.Message
urls types.URLs
connc chan *outgoingConn
}
func newFakePeer() *fakePeer {
@ -352,6 +354,7 @@ func newFakePeer() *fakePeer {
}
func (pr *fakePeer) send(m raftpb.Message) { pr.msgs = append(pr.msgs, m) }
func (pr *fakePeer) sendSnap(m snap.Message) { pr.snapMsgs = append(pr.snapMsgs, m) }
func (pr *fakePeer) update(urls types.URLs) { pr.urls = urls }
func (pr *fakePeer) attachOutgoingConn(conn *outgoingConn) { pr.connc <- conn }
func (pr *fakePeer) activeSince() time.Time { return time.Time{} }

18
rafthttp/peer.go
View File

@ -23,6 +23,7 @@ import (
"github.com/coreos/etcd/pkg/types"
"github.com/coreos/etcd/raft"
"github.com/coreos/etcd/raft/raftpb"
"github.com/coreos/etcd/snap"
)
const (
@ -57,6 +58,11 @@ type Peer interface {
// When it fails to send message out, it will report the status to underlying
// raft.
send(m raftpb.Message)
// sendSanp sends the merged snapshot message to the remote peer. Its behavior
// is similar to send.
sendSnap(m snap.Message)
// update updates the urls of remote peer.
update(urls types.URLs)
// attachOutgoingConn attachs the outgoing connection to the peer for
@ -110,7 +116,7 @@ type peer struct {
done chan struct{}
}
func startPeer(streamRt, pipelineRt http.RoundTripper, urls types.URLs, local, to, cid types.ID, snapst *snapshotStore, r Raft, fs *stats.FollowerStats, errorc chan error, v3demo bool) *peer {
func startPeer(streamRt, pipelineRt http.RoundTripper, urls types.URLs, local, to, cid types.ID, r Raft, fs *stats.FollowerStats, errorc chan error, v3demo bool) *peer {
picker := newURLPicker(urls)
status := newPeerStatus(to)
p := &peer{
@ -121,7 +127,7 @@ func startPeer(streamRt, pipelineRt http.RoundTripper, urls types.URLs, local, t
msgAppV2Writer: startStreamWriter(to, status, fs, r),
writer: startStreamWriter(to, status, fs, r),
pipeline: newPipeline(pipelineRt, picker, local, to, cid, status, fs, r, errorc),
snapSender: newSnapshotSender(pipelineRt, picker, local, to, cid, status, snapst, r, errorc),
snapSender: newSnapshotSender(pipelineRt, picker, local, to, cid, status, r, errorc),
sendc: make(chan raftpb.Message),
recvc: make(chan raftpb.Message, recvBufSize),
propc: make(chan raftpb.Message, maxPendingProposals),
@ -158,10 +164,6 @@ func startPeer(streamRt, pipelineRt http.RoundTripper, urls types.URLs, local, t
if paused {
continue
}
if p.v3demo && isMsgSnap(m) {
go p.snapSender.send(m)
continue
}
writec, name := p.pick(m)
select {
case writec <- m:
@ -209,6 +211,10 @@ func (p *peer) send(m raftpb.Message) {
}
}
func (p *peer) sendSnap(m snap.Message) {
go p.snapSender.send(m)
}
func (p *peer) update(urls types.URLs) {
select {
case p.newURLsC <- urls:

24
rafthttp/snapshot_sender.go
View File

@ -24,7 +24,7 @@ import (
"github.com/coreos/etcd/pkg/httputil"
"github.com/coreos/etcd/pkg/types"
"github.com/coreos/etcd/raft"
"github.com/coreos/etcd/raft/raftpb"
"github.com/coreos/etcd/snap"
)
type snapshotSender struct {
@ -34,14 +34,13 @@ type snapshotSender struct {
tr http.RoundTripper
picker *urlPicker
status *peerStatus
snapst *snapshotStore
r Raft
errorc chan error
stopc chan struct{}
}
func newSnapshotSender(tr http.RoundTripper, picker *urlPicker, from, to, cid types.ID, status *peerStatus, snapst *snapshotStore, r Raft, errorc chan error) *snapshotSender {
func newSnapshotSender(tr http.RoundTripper, picker *urlPicker, from, to, cid types.ID, status *peerStatus, r Raft, errorc chan error) *snapshotSender {
return &snapshotSender{
from: from,
to: to,
@ -49,7 +48,6 @@ func newSnapshotSender(tr http.RoundTripper, picker *urlPicker, from, to, cid ty
tr: tr,
picker: picker,
status: status,
snapst: snapst,
r: r,
errorc: errorc,
stopc: make(chan struct{}),
@ -58,10 +56,12 @@ func newSnapshotSender(tr http.RoundTripper, picker *urlPicker, from, to, cid ty
func (s *snapshotSender) stop() { close(s.stopc) }
func (s *snapshotSender) send(m raftpb.Message) {
func (s *snapshotSender) send(merged snap.Message) {
m := merged.Message
start := time.Now()
body := createSnapBody(m, s.snapst)
body := createSnapBody(merged)
defer body.Close()
u := s.picker.pick()
@ -142,20 +142,16 @@ type readCloser struct {
io.Closer
}
// createSnapBody creates the request body for the given raft snapshot message.
// Callers should close body when done reading from it.
func createSnapBody(m raftpb.Message, snapst *snapshotStore) io.ReadCloser {
func createSnapBody(merged snap.Message) io.ReadCloser {
buf := new(bytes.Buffer)
enc := &messageEncoder{w: buf}
// encode raft message
if err := enc.encode(m); err != nil {
if err := enc.encode(merged.Message); err != nil {
plog.Panicf("encode message error (%v)", err)
}
// get snapshot
rc := snapst.get(m.Snapshot.Metadata.Index)
return &readCloser{
Reader: io.MultiReader(buf, rc),
Closer: rc,
Reader: io.MultiReader(buf, merged.ReadCloser),
Closer: merged.ReadCloser,
}
}

45
rafthttp/snapshot_store.go
View File

@ -1,45 +0,0 @@
// 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 rafthttp
import (
"io"
)
// snapshotStore is the store of snapshot. Caller could put one
// snapshot into the store, and get it later.
// snapshotStore stores at most one snapshot at a time, or it panics.
type snapshotStore struct {
rc io.ReadCloser
// index of the stored snapshot
// index is 0 if and only if there is no snapshot stored.
index uint64
}
func (s *snapshotStore) put(rc io.ReadCloser, index uint64) {
if s.index != 0 {
plog.Panicf("unexpected put when there is one snapshot stored")
}
s.rc, s.index = rc, index
}
func (s *snapshotStore) get(index uint64) io.ReadCloser {
if s.index == index {
// set index to 0 to indicate no snapshot stored
s.index = 0
return s.rc
}
return nil
}

43
rafthttp/transport.go
View File

@ -15,7 +15,6 @@
package rafthttp
import (
"io"
"net/http"
"sync"
"time"
@ -29,6 +28,7 @@ import (
"github.com/coreos/etcd/pkg/types"
"github.com/coreos/etcd/raft"
"github.com/coreos/etcd/raft/raftpb"
"github.com/coreos/etcd/snap"
)
var plog = logutil.NewMergeLogger(capnslog.NewPackageLogger("github.com/coreos/etcd", "rafthttp"))
@ -40,12 +40,6 @@ type Raft interface {
ReportSnapshot(id uint64, status raft.SnapshotStatus)
}
// SnapshotSaver is the interface that wraps the SaveFrom method.
type SnapshotSaver interface {
// SaveFrom saves the snapshot data at the given index from the given reader.
SaveFrom(r io.Reader, index uint64) error
}
type Transporter interface {
// Start starts the given Transporter.
// Start MUST be called before calling other functions in the interface.
@ -62,6 +56,9 @@ type Transporter interface {
// If the id cannot be found in the transport, the message
// will be ignored.
Send(m []raftpb.Message)
// SendSnapshot sends out the given snapshot message to a remote peer.
// The behavior of SendSnapshot is similar to Send.
SendSnapshot(m snap.Message)
// AddRemote adds a remote with given peer urls into the transport.
// A remote helps newly joined member to catch up the progress of cluster,
// and will not be used after that.
@ -86,14 +83,6 @@ type Transporter interface {
// If the connection is active since peer was added, it returns the adding time.
// If the connection is currently inactive, it returns zero time.
ActiveSince(id types.ID) time.Time
// SnapshotReady accepts a snapshot at the given index that is ready to send out.
// It is expected that caller sends a raft snapshot message with
// the given index soon, and the accepted snapshot will be sent out
// together. After sending, snapshot sent status is reported
// through Raft.SnapshotStatus.
// SnapshotReady MUST not be called when the snapshot sent status of previous
// accepted one has not been reported.
SnapshotReady(rc io.ReadCloser, index uint64)
// Stop closes the connections and stops the transporter.
Stop()
}
@ -108,10 +97,10 @@ type Transport struct {
DialTimeout time.Duration // maximum duration before timing out dial of the request
TLSInfo transport.TLSInfo // TLS information used when creating connection
ID types.ID // local member ID
ClusterID types.ID // raft cluster ID for request validation
Raft Raft // raft state machine, to which the Transport forwards received messages and reports status
SnapSaver SnapshotSaver // used to save snapshot in v3 snapshot messages
ID types.ID // local member ID
ClusterID types.ID // raft cluster ID for request validation
Raft Raft // raft state machine, to which the Transport forwards received messages and reports status
Snapshotter *snap.Snapshotter
ServerStats *stats.ServerStats // used to record general transportation statistics
// used to record transportation statistics with followers when
// performing as leader in raft protocol
@ -130,8 +119,6 @@ type Transport struct {
remotes map[types.ID]*remote // remotes map that helps newly joined member to catch up
peers map[types.ID]Peer // peers map
snapst *snapshotStore
prober probing.Prober
}
@ -147,7 +134,6 @@ func (t *Transport) Start() error {
}
t.remotes = make(map[types.ID]*remote)
t.peers = make(map[types.ID]Peer)
t.snapst = &snapshotStore{}
t.prober = probing.NewProber(t.pipelineRt)
return nil
}
@ -155,7 +141,7 @@ func (t *Transport) Start() error {
func (t *Transport) Handler() http.Handler {
pipelineHandler := newPipelineHandler(t.Raft, t.ClusterID)
streamHandler := newStreamHandler(t, t.Raft, t.ID, t.ClusterID)
snapHandler := newSnapshotHandler(t.Raft, t.SnapSaver, t.ClusterID)
snapHandler := newSnapshotHandler(t.Raft, t.Snapshotter, t.ClusterID)
mux := http.NewServeMux()
mux.Handle(RaftPrefix, pipelineHandler)
mux.Handle(RaftStreamPrefix+"/", streamHandler)
@ -240,7 +226,7 @@ func (t *Transport) AddPeer(id types.ID, us []string) {
plog.Panicf("newURLs %+v should never fail: %+v", us, err)
}
fs := t.LeaderStats.Follower(id.String())
t.peers[id] = startPeer(t.streamRt, t.pipelineRt, urls, t.ID, id, t.ClusterID, t.snapst, t.Raft, fs, t.ErrorC, t.V3demo)
t.peers[id] = startPeer(t.streamRt, t.pipelineRt, urls, t.ID, id, t.ClusterID, t.Raft, fs, t.ErrorC, t.V3demo)
addPeerToProber(t.prober, id.String(), us)
}
@ -296,8 +282,13 @@ func (t *Transport) ActiveSince(id types.ID) time.Time {
return time.Time{}
}
func (t *Transport) SnapshotReady(rc io.ReadCloser, index uint64) {
t.snapst.put(rc, index)
func (t *Transport) SendSnapshot(m snap.Message) {
p := t.peers[types.ID(m.To)]
if p == nil {
m.ReadCloser.Close()
return
}
p.sendSnap(m)
}
type Pausable interface {

67
snap/db.go Normal file
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@ -0,0 +1,67 @@
// 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 snap
import (
"fmt"
"io"
"io/ioutil"
"os"
"path"
"github.com/coreos/etcd/pkg/fileutil"
)
// SaveDBFrom saves snapshot of the database from the given reader. It
// guarantees the save operation is atomic.
func (s *Snapshotter) SaveDBFrom(r io.Reader, id uint64) error {
f, err := ioutil.TempFile(s.dir, "tmp")
if err != nil {
return err
}
_, err = io.Copy(f, r)
f.Close()
if err != nil {
os.Remove(f.Name())
return err
}
fn := path.Join(s.dir, fmt.Sprintf("%016x.snap.db", id))
if fileutil.Exist(fn) {
os.Remove(f.Name())
return nil
}
err = os.Rename(f.Name(), fn)
if err != nil {
os.Remove(f.Name())
return err
}
return nil
}
// DBFilePath returns the file path for the snapshot of the database with
// given id. If the snapshot does not exist, it returns error.
func (s *Snapshotter) DBFilePath(id uint64) (string, error) {
fns, err := fileutil.ReadDir(s.dir)
if err != nil {
return "", err
}
wfn := fmt.Sprintf("%016x.snap.db", id)
for _, fn := range fns {
if fn == wfn {
return path.Join(s.dir, fn), nil
}
}
return "", fmt.Errorf("snap: snapshot file doesn't exist")
}

34
snap/message.go Normal file
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@ -0,0 +1,34 @@
// 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 snap
import (
"io"
"github.com/coreos/etcd/raft/raftpb"
)
// Message is a struct that contains a raft Message and a ReadCloser. The type
// of raft message MUST be MsgSnap, which contains the raft meta-data and an
// additional data []byte field that contains the snapshot of the actual state
// machine.
// Message contains the ReadCloser field for handling large snapshot. This avoid
// copying the entire snapshot into a byte array, which consumes a lot of memory.
//
// User of Message should close the ReadCloser after sending it.
type Message struct {
raftpb.Message
ReadCloser io.ReadCloser
}