mirror of
https://github.com/moby/moby.git
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105 lines
2.4 KiB
Go
105 lines
2.4 KiB
Go
// Copyright 2016 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 wal
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import (
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"fmt"
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"os"
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"path/filepath"
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"go.etcd.io/etcd/client/pkg/v3/fileutil"
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"go.uber.org/zap"
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)
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// filePipeline pipelines allocating disk space
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type filePipeline struct {
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lg *zap.Logger
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// dir to put files
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dir string
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// size of files to make, in bytes
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size int64
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// count number of files generated
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count int
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filec chan *fileutil.LockedFile
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errc chan error
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donec chan struct{}
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}
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func newFilePipeline(lg *zap.Logger, dir string, fileSize int64) *filePipeline {
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if lg == nil {
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lg = zap.NewNop()
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}
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fp := &filePipeline{
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lg: lg,
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dir: dir,
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size: fileSize,
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filec: make(chan *fileutil.LockedFile),
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errc: make(chan error, 1),
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donec: make(chan struct{}),
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}
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go fp.run()
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return fp
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}
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// Open returns a fresh file for writing. Rename the file before calling
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// Open again or there will be file collisions.
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func (fp *filePipeline) Open() (f *fileutil.LockedFile, err error) {
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select {
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case f = <-fp.filec:
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case err = <-fp.errc:
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}
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return f, err
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}
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func (fp *filePipeline) Close() error {
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close(fp.donec)
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return <-fp.errc
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}
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func (fp *filePipeline) alloc() (f *fileutil.LockedFile, err error) {
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// count % 2 so this file isn't the same as the one last published
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fpath := filepath.Join(fp.dir, fmt.Sprintf("%d.tmp", fp.count%2))
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if f, err = fileutil.LockFile(fpath, os.O_CREATE|os.O_WRONLY, fileutil.PrivateFileMode); err != nil {
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return nil, err
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}
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if err = fileutil.Preallocate(f.File, fp.size, true); err != nil {
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fp.lg.Error("failed to preallocate space when creating a new WAL", zap.Int64("size", fp.size), zap.Error(err))
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f.Close()
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return nil, err
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}
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fp.count++
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return f, nil
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}
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func (fp *filePipeline) run() {
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defer close(fp.errc)
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for {
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f, err := fp.alloc()
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if err != nil {
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fp.errc <- err
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return
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}
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select {
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case fp.filec <- f:
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case <-fp.donec:
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os.Remove(f.Name())
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f.Close()
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return
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}
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}
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}
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