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https://github.com/etcd-io/etcd.git
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f6cd4d4f5b
Computing the snapshot file path is error prone; snapshot recovery was constructing file paths missing a path separator so the snapshot would never be loaded. Instead, refactor the backend path handling to use helper functions where possible.
82 lines
2.8 KiB
Go
82 lines
2.8 KiB
Go
// Copyright 2017 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 etcdserver
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import (
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"fmt"
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"os"
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"time"
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"github.com/coreos/etcd/lease"
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"github.com/coreos/etcd/mvcc"
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"github.com/coreos/etcd/mvcc/backend"
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"github.com/coreos/etcd/raft/raftpb"
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"github.com/coreos/etcd/snap"
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)
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func newBackend(cfg *ServerConfig) backend.Backend {
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bcfg := backend.DefaultBackendConfig()
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bcfg.Path = cfg.backendPath()
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if cfg.QuotaBackendBytes > 0 && cfg.QuotaBackendBytes != DefaultQuotaBytes {
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// permit 10% excess over quota for disarm
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bcfg.MmapSize = uint64(cfg.QuotaBackendBytes + cfg.QuotaBackendBytes/10)
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}
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return backend.New(bcfg)
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}
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// openSnapshotBackend renames a snapshot db to the current etcd db and opens it.
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func openSnapshotBackend(cfg *ServerConfig, ss *snap.Snapshotter, snapshot raftpb.Snapshot) (backend.Backend, error) {
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snapPath, err := ss.DBFilePath(snapshot.Metadata.Index)
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if err != nil {
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return nil, fmt.Errorf("database snapshot file path error: %v", err)
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}
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if err := os.Rename(snapPath, cfg.backendPath()); err != nil {
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return nil, fmt.Errorf("rename snapshot file error: %v", err)
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}
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return openBackend(cfg), nil
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}
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// openBackend returns a backend using the current etcd db.
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func openBackend(cfg *ServerConfig) backend.Backend {
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fn := cfg.backendPath()
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beOpened := make(chan backend.Backend)
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go func() {
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beOpened <- newBackend(cfg)
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}()
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select {
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case be := <-beOpened:
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return be
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case <-time.After(time.Second):
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plog.Warningf("another etcd process is using %q and holds the file lock.", fn)
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plog.Warningf("waiting for it to exit before starting...")
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}
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return <-beOpened
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}
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// recoverBackendSnapshot recovers the DB from a snapshot in case etcd crashes
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// before updating the backend db after persisting raft snapshot to disk,
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// violating the invariant snapshot.Metadata.Index < db.consistentIndex. In this
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// case, replace the db with the snapshot db sent by the leader.
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func recoverSnapshotBackend(cfg *ServerConfig, oldbe backend.Backend, snapshot raftpb.Snapshot) (backend.Backend, error) {
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var cIndex consistentIndex
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kv := mvcc.New(oldbe, &lease.FakeLessor{}, &cIndex)
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defer kv.Close()
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if snapshot.Metadata.Index <= kv.ConsistentIndex() {
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return oldbe, nil
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}
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oldbe.Close()
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return openSnapshotBackend(cfg, snap.New(cfg.SnapDir()), snapshot)
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}
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