135 lines
3.7 KiB
Go
135 lines
3.7 KiB
Go
// Copyright 2015 The etcd Authors
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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 storage
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import (
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"sync"
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"github.com/coreos/go-semver/semver"
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"go.uber.org/zap"
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"go.etcd.io/etcd/server/v3/etcdserver/api/snap"
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"go.etcd.io/etcd/server/v3/storage/wal"
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"go.etcd.io/etcd/server/v3/storage/wal/walpb"
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"go.etcd.io/raft/v3/raftpb"
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)
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type Storage interface {
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// Save function saves ents and state to the underlying stable storage.
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// Save MUST block until st and ents are on stable storage.
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Save(st raftpb.HardState, ents []raftpb.Entry) error
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// SaveSnap function saves snapshot to the underlying stable storage.
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SaveSnap(snap raftpb.Snapshot) error
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// Close closes the Storage and performs finalization.
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Close() error
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// Release releases the locked wal files older than the provided snapshot.
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Release(snap raftpb.Snapshot) error
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// Sync WAL
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Sync() error
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// MinimalEtcdVersion returns minimal etcd storage able to interpret WAL log.
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MinimalEtcdVersion() *semver.Version
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}
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type storage struct {
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lg *zap.Logger
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s *snap.Snapshotter
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// Mutex protected variables
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mux sync.RWMutex
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w *wal.WAL
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}
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func NewStorage(lg *zap.Logger, w *wal.WAL, s *snap.Snapshotter) Storage {
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return &storage{lg: lg, w: w, s: s}
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}
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// SaveSnap saves the snapshot file to disk and writes the WAL snapshot entry.
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func (st *storage) SaveSnap(snap raftpb.Snapshot) error {
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st.mux.RLock()
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defer st.mux.RUnlock()
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walsnap := walpb.Snapshot{
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Index: snap.Metadata.Index,
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Term: snap.Metadata.Term,
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ConfState: &snap.Metadata.ConfState,
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}
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// save the snapshot file before writing the snapshot to the wal.
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// This makes it possible for the snapshot file to become orphaned, but prevents
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// a WAL snapshot entry from having no corresponding snapshot file.
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err := st.s.SaveSnap(snap)
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if err != nil {
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return err
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}
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// gofail: var raftBeforeWALSaveSnaphot struct{}
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return st.w.SaveSnapshot(walsnap)
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}
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// Release releases resources older than the given snap and are no longer needed:
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// - releases the locks to the wal files that are older than the provided wal for the given snap.
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// - deletes any .snap.db files that are older than the given snap.
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func (st *storage) Release(snap raftpb.Snapshot) error {
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st.mux.RLock()
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defer st.mux.RUnlock()
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if err := st.w.ReleaseLockTo(snap.Metadata.Index); err != nil {
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return err
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}
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return st.s.ReleaseSnapDBs(snap)
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}
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func (st *storage) Save(s raftpb.HardState, ents []raftpb.Entry) error {
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st.mux.RLock()
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defer st.mux.RUnlock()
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return st.w.Save(s, ents)
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}
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func (st *storage) Close() error {
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st.mux.Lock()
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defer st.mux.Unlock()
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return st.w.Close()
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}
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func (st *storage) Sync() error {
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st.mux.RLock()
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defer st.mux.RUnlock()
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return st.w.Sync()
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}
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func (st *storage) MinimalEtcdVersion() *semver.Version {
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st.mux.Lock()
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defer st.mux.Unlock()
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walsnap := walpb.Snapshot{}
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sn, err := st.s.Load()
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if err != nil && err != snap.ErrNoSnapshot {
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panic(err)
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}
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if sn != nil {
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walsnap.Index = sn.Metadata.Index
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walsnap.Term = sn.Metadata.Term
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walsnap.ConfState = &sn.Metadata.ConfState
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}
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w, err := st.w.Reopen(st.lg, walsnap)
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if err != nil {
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panic(err)
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}
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_, _, ents, err := w.ReadAll()
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if err != nil {
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panic(err)
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}
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v := wal.MinimalEtcdVersion(ents)
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st.w = w
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return v
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}
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