mirror of
https://github.com/chrislusf/seaweedfs
synced 2024-09-12 20:10:41 +02:00
146 lines
4 KiB
Go
146 lines
4 KiB
Go
package chunk_cache
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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/syndtr/goleveldb/leveldb/opt"
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"github.com/chrislusf/seaweedfs/weed/glog"
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"github.com/chrislusf/seaweedfs/weed/storage"
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"github.com/chrislusf/seaweedfs/weed/storage/backend"
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"github.com/chrislusf/seaweedfs/weed/storage/types"
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"github.com/chrislusf/seaweedfs/weed/util"
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)
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// This implements an on disk cache
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// The entries are an FIFO with a size limit
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type ChunkCacheVolume struct {
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DataBackend backend.BackendStorageFile
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nm storage.NeedleMapper
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fileName string
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smallBuffer []byte
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sizeLimit int64
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lastModTime time.Time
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fileSize int64
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}
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func LoadOrCreateChunkCacheVolume(fileName string, preallocate int64) (*ChunkCacheVolume, error) {
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v := &ChunkCacheVolume{
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smallBuffer: make([]byte, types.NeedlePaddingSize),
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fileName: fileName,
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sizeLimit: preallocate,
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}
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var err error
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if exists, canRead, canWrite, modTime, fileSize := util.CheckFile(v.fileName + ".dat"); exists {
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if !canRead {
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return nil, fmt.Errorf("cannot read cache file %s.dat", v.fileName)
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}
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if !canWrite {
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return nil, fmt.Errorf("cannot write cache file %s.dat", v.fileName)
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}
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if dataFile, err := os.OpenFile(v.fileName+".dat", os.O_RDWR|os.O_CREATE, 0644); err != nil {
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return nil, fmt.Errorf("cannot create cache file %s.dat: %v", v.fileName, err)
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} else {
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v.DataBackend = backend.NewDiskFile(dataFile)
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v.lastModTime = modTime
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v.fileSize = fileSize
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}
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} else {
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if v.DataBackend, err = backend.CreateVolumeFile(v.fileName+".dat", preallocate, 0); err != nil {
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return nil, fmt.Errorf("cannot create cache file %s.dat: %v", v.fileName, err)
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}
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v.lastModTime = time.Now()
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}
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var indexFile *os.File
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if indexFile, err = os.OpenFile(v.fileName+".idx", os.O_RDWR|os.O_CREATE, 0644); err != nil {
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return nil, fmt.Errorf("cannot write cache index %s.idx: %v", v.fileName, err)
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}
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glog.V(1).Infoln("loading leveldb", v.fileName+".ldb")
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opts := &opt.Options{
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BlockCacheCapacity: 2 * 1024 * 1024, // default value is 8MiB
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WriteBuffer: 1 * 1024 * 1024, // default value is 4MiB
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CompactionTableSizeMultiplier: 10, // default value is 1
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}
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if v.nm, err = storage.NewLevelDbNeedleMap(v.fileName+".ldb", indexFile, opts); err != nil {
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return nil, fmt.Errorf("loading leveldb %s error: %v", v.fileName+".ldb", err)
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}
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return v, nil
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}
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func (v *ChunkCacheVolume) Shutdown() {
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if v.DataBackend != nil {
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v.DataBackend.Close()
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v.DataBackend = nil
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}
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if v.nm != nil {
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v.nm.Close()
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v.nm = nil
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}
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}
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func (v *ChunkCacheVolume) destroy() {
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v.Shutdown()
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os.Remove(v.fileName + ".dat")
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os.Remove(v.fileName + ".idx")
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os.RemoveAll(v.fileName + ".ldb")
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}
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func (v *ChunkCacheVolume) Reset() (*ChunkCacheVolume, error) {
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v.destroy()
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return LoadOrCreateChunkCacheVolume(v.fileName, v.sizeLimit)
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}
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func (v *ChunkCacheVolume) GetNeedle(key types.NeedleId) ([]byte, error) {
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nv, ok := v.nm.Get(key)
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if !ok {
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return nil, storage.ErrorNotFound
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}
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data := make([]byte, nv.Size)
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if readSize, readErr := v.DataBackend.ReadAt(data, nv.Offset.ToAcutalOffset()); readErr != nil {
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return nil, fmt.Errorf("read %s.dat [%d,%d): %v",
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v.fileName, nv.Offset.ToAcutalOffset(), nv.Offset.ToAcutalOffset()+int64(nv.Size), readErr)
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} else {
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if readSize != int(nv.Size) {
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return nil, fmt.Errorf("read %d, expected %d", readSize, nv.Size)
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}
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}
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return data, nil
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}
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func (v *ChunkCacheVolume) WriteNeedle(key types.NeedleId, data []byte) error {
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offset := v.fileSize
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written, err := v.DataBackend.WriteAt(data, offset)
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if err != nil {
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return err
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} else if written != len(data) {
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return fmt.Errorf("partial written %d, expected %d", written, len(data))
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}
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v.fileSize += int64(written)
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extraSize := written % types.NeedlePaddingSize
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if extraSize != 0 {
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v.DataBackend.WriteAt(v.smallBuffer[:types.NeedlePaddingSize-extraSize], offset+int64(written))
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v.fileSize += int64(types.NeedlePaddingSize - extraSize)
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}
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if err := v.nm.Put(key, types.ToOffset(offset), types.Size(len(data))); err != nil {
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return err
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}
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return nil
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}
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