package autofile import ( "bufio" "errors" "fmt" "io" "os" "path/filepath" "regexp" "strconv" "strings" "sync" "time" "github.com/tendermint/tendermint/libs/service" ) const ( defaultGroupCheckDuration = 5000 * time.Millisecond defaultHeadSizeLimit = 10 * 1024 * 1024 // 10MB defaultTotalSizeLimit = 1 * 1024 * 1024 * 1024 // 1GB maxFilesToRemove = 4 // needs to be greater than 1 ) /* You can open a Group to keep restrictions on an AutoFile, like the maximum size of each chunk, and/or the total amount of bytes stored in the group. The first file to be written in the Group.Dir is the head file. Dir/ - Once the Head file reaches the size limit, it will be rotated. Dir/ - .000 // First rolled file - // New head path, starts empty. // The implicit index is 001. As more files are written, the index numbers grow... Dir/ - .000 // First rolled file - .001 // Second rolled file - ... - // New head path The Group can also be used to binary-search for some line, assuming that marker lines are written occasionally. */ type Group struct { service.BaseService ID string Head *AutoFile // The head AutoFile to write to headBuf *bufio.Writer Dir string // Directory that contains .Head ticker *time.Ticker mtx sync.Mutex headSizeLimit int64 totalSizeLimit int64 groupCheckDuration time.Duration minIndex int // Includes head maxIndex int // Includes head, where Head will move to // close this when the processTicks routine is done. // this ensures we can cleanup the dir after calling Stop // and the routine won't be trying to access it anymore doneProcessTicks chan struct{} // TODO: When we start deleting files, we need to start tracking GroupReaders // and their dependencies. } // OpenGroup creates a new Group with head at headPath. It returns an error if // it fails to open head file. func OpenGroup(headPath string, groupOptions ...func(*Group)) (*Group, error) { dir, err := filepath.Abs(filepath.Dir(headPath)) if err != nil { return nil, err } head, err := OpenAutoFile(headPath) if err != nil { return nil, err } g := &Group{ ID: "group:" + head.ID, Head: head, headBuf: bufio.NewWriterSize(head, 4096*10), Dir: dir, headSizeLimit: defaultHeadSizeLimit, totalSizeLimit: defaultTotalSizeLimit, groupCheckDuration: defaultGroupCheckDuration, minIndex: 0, maxIndex: 0, doneProcessTicks: make(chan struct{}), } for _, option := range groupOptions { option(g) } g.BaseService = *service.NewBaseService(nil, "Group", g) gInfo := g.readGroupInfo() g.minIndex = gInfo.MinIndex g.maxIndex = gInfo.MaxIndex return g, nil } // GroupCheckDuration allows you to overwrite default groupCheckDuration. func GroupCheckDuration(duration time.Duration) func(*Group) { return func(g *Group) { g.groupCheckDuration = duration } } // GroupHeadSizeLimit allows you to overwrite default head size limit - 10MB. func GroupHeadSizeLimit(limit int64) func(*Group) { return func(g *Group) { g.headSizeLimit = limit } } // GroupTotalSizeLimit allows you to overwrite default total size limit of the group - 1GB. func GroupTotalSizeLimit(limit int64) func(*Group) { return func(g *Group) { g.totalSizeLimit = limit } } // OnStart implements service.Service by starting the goroutine that checks file // and group limits. func (g *Group) OnStart() error { g.ticker = time.NewTicker(g.groupCheckDuration) go g.processTicks() return nil } // OnStop implements service.Service by stopping the goroutine described above. // NOTE: g.Head must be closed separately using Close. func (g *Group) OnStop() { g.ticker.Stop() g.FlushAndSync() } // Wait blocks until all internal goroutines are finished. Supposed to be // called after Stop. func (g *Group) Wait() { // wait for processTicks routine to finish <-g.doneProcessTicks } // Close closes the head file. The group must be stopped by this moment. func (g *Group) Close() { g.FlushAndSync() g.mtx.Lock() _ = g.Head.closeFile() g.mtx.Unlock() } // HeadSizeLimit returns the current head size limit. func (g *Group) HeadSizeLimit() int64 { g.mtx.Lock() defer g.mtx.Unlock() return g.headSizeLimit } // TotalSizeLimit returns total size limit of the group. func (g *Group) TotalSizeLimit() int64 { g.mtx.Lock() defer g.mtx.Unlock() return g.totalSizeLimit } // MaxIndex returns index of the last file in the group. func (g *Group) MaxIndex() int { g.mtx.Lock() defer g.mtx.Unlock() return g.maxIndex } // MinIndex returns index of the first file in the group. func (g *Group) MinIndex() int { g.mtx.Lock() defer g.mtx.Unlock() return g.minIndex } // Write writes the contents of p into the current head of the group. It // returns the number of bytes written. If nn < len(p), it also returns an // error explaining why the write is short. // NOTE: Writes are buffered so they don't write synchronously // TODO: Make it halt if space is unavailable func (g *Group) Write(p []byte) (nn int, err error) { g.mtx.Lock() defer g.mtx.Unlock() return g.headBuf.Write(p) } // WriteLine writes line into the current head of the group. It also appends "\n". // NOTE: Writes are buffered so they don't write synchronously // TODO: Make it halt if space is unavailable func (g *Group) WriteLine(line string) error { g.mtx.Lock() defer g.mtx.Unlock() _, err := g.headBuf.Write([]byte(line + "\n")) return err } // Buffered returns the size of the currently buffered data. func (g *Group) Buffered() int { g.mtx.Lock() defer g.mtx.Unlock() return g.headBuf.Buffered() } // FlushAndSync writes any buffered data to the underlying file and commits the // current content of the file to stable storage (fsync). func (g *Group) FlushAndSync() error { g.mtx.Lock() defer g.mtx.Unlock() err := g.headBuf.Flush() if err == nil { err = g.Head.Sync() } return err } func (g *Group) processTicks() { defer close(g.doneProcessTicks) for { select { case <-g.ticker.C: g.checkHeadSizeLimit() g.checkTotalSizeLimit() case <-g.Quit(): return } } } // NOTE: this function is called manually in tests. func (g *Group) checkHeadSizeLimit() { limit := g.HeadSizeLimit() if limit == 0 { return } size, err := g.Head.Size() if err != nil { g.Logger.Error("Group's head may grow without bound", "head", g.Head.Path, "err", err) return } if size >= limit { g.RotateFile() } } func (g *Group) checkTotalSizeLimit() { limit := g.TotalSizeLimit() if limit == 0 { return } gInfo := g.readGroupInfo() totalSize := gInfo.TotalSize for i := 0; i < maxFilesToRemove; i++ { index := gInfo.MinIndex + i if totalSize < limit { return } if index == gInfo.MaxIndex { // Special degenerate case, just do nothing. g.Logger.Error("Group's head may grow without bound", "head", g.Head.Path) return } pathToRemove := filePathForIndex(g.Head.Path, index, gInfo.MaxIndex) fInfo, err := os.Stat(pathToRemove) if err != nil { g.Logger.Error("Failed to fetch info for file", "file", pathToRemove) continue } err = os.Remove(pathToRemove) if err != nil { g.Logger.Error("Failed to remove path", "path", pathToRemove) return } totalSize -= fInfo.Size() } } // RotateFile causes group to close the current head and assign it some index. // Note it does not create a new head. func (g *Group) RotateFile() { g.mtx.Lock() defer g.mtx.Unlock() headPath := g.Head.Path if err := g.headBuf.Flush(); err != nil { panic(err) } if err := g.Head.Sync(); err != nil { panic(err) } if err := g.Head.closeFile(); err != nil { panic(err) } indexPath := filePathForIndex(headPath, g.maxIndex, g.maxIndex+1) if err := os.Rename(headPath, indexPath); err != nil { panic(err) } g.maxIndex++ } // NewReader returns a new group reader. // CONTRACT: Caller must close the returned GroupReader. func (g *Group) NewReader(index int) (*GroupReader, error) { r := newGroupReader(g) err := r.SetIndex(index) if err != nil { return nil, err } return r, nil } // GroupInfo holds information about the group. type GroupInfo struct { MinIndex int // index of the first file in the group, including head MaxIndex int // index of the last file in the group, including head TotalSize int64 // total size of the group HeadSize int64 // size of the head } // Returns info after scanning all files in g.Head's dir. func (g *Group) ReadGroupInfo() GroupInfo { g.mtx.Lock() defer g.mtx.Unlock() return g.readGroupInfo() } // Index includes the head. // CONTRACT: caller should have called g.mtx.Lock func (g *Group) readGroupInfo() GroupInfo { groupDir := filepath.Dir(g.Head.Path) headBase := filepath.Base(g.Head.Path) var minIndex, maxIndex int = -1, -1 var totalSize, headSize int64 = 0, 0 dir, err := os.Open(groupDir) if err != nil { panic(err) } defer dir.Close() fiz, err := dir.Readdir(0) if err != nil { panic(err) } // For each file in the directory, filter by pattern for _, fileInfo := range fiz { if fileInfo.Name() == headBase { fileSize := fileInfo.Size() totalSize += fileSize headSize = fileSize continue } else if strings.HasPrefix(fileInfo.Name(), headBase) { fileSize := fileInfo.Size() totalSize += fileSize indexedFilePattern := regexp.MustCompile(`^.+\.([0-9]{3,})$`) submatch := indexedFilePattern.FindSubmatch([]byte(fileInfo.Name())) if len(submatch) != 0 { // Matches fileIndex, err := strconv.Atoi(string(submatch[1])) if err != nil { panic(err) } if maxIndex < fileIndex { maxIndex = fileIndex } if minIndex == -1 || fileIndex < minIndex { minIndex = fileIndex } } } } // Now account for the head. if minIndex == -1 { // If there were no numbered files, // then the head is index 0. minIndex, maxIndex = 0, 0 } else { // Otherwise, the head file is 1 greater maxIndex++ } return GroupInfo{minIndex, maxIndex, totalSize, headSize} } func filePathForIndex(headPath string, index int, maxIndex int) string { if index == maxIndex { return headPath } return fmt.Sprintf("%v.%03d", headPath, index) } //-------------------------------------------------------------------------------- // GroupReader provides an interface for reading from a Group. type GroupReader struct { *Group mtx sync.Mutex curIndex int curFile *os.File curReader *bufio.Reader curLine []byte } func newGroupReader(g *Group) *GroupReader { return &GroupReader{ Group: g, curIndex: 0, curFile: nil, curReader: nil, curLine: nil, } } // Close closes the GroupReader by closing the cursor file. func (gr *GroupReader) Close() error { gr.mtx.Lock() defer gr.mtx.Unlock() if gr.curReader != nil { err := gr.curFile.Close() gr.curIndex = 0 gr.curReader = nil gr.curFile = nil gr.curLine = nil return err } return nil } // Read implements io.Reader, reading bytes from the current Reader // incrementing index until enough bytes are read. func (gr *GroupReader) Read(p []byte) (n int, err error) { lenP := len(p) if lenP == 0 { return 0, errors.New("given empty slice") } gr.mtx.Lock() defer gr.mtx.Unlock() // Open file if not open yet if gr.curReader == nil { if err = gr.openFile(gr.curIndex); err != nil { return 0, err } } // Iterate over files until enough bytes are read var nn int for { nn, err = gr.curReader.Read(p[n:]) n += nn switch { case err == io.EOF: if n >= lenP { return n, nil } // Open the next file if err1 := gr.openFile(gr.curIndex + 1); err1 != nil { return n, err1 } case err != nil: return n, err case nn == 0: // empty file return n, err } } } // IF index > gr.Group.maxIndex, returns io.EOF // CONTRACT: caller should hold gr.mtx func (gr *GroupReader) openFile(index int) error { // Lock on Group to ensure that head doesn't move in the meanwhile. gr.Group.mtx.Lock() defer gr.Group.mtx.Unlock() if index > gr.Group.maxIndex { return io.EOF } curFilePath := filePathForIndex(gr.Head.Path, index, gr.Group.maxIndex) curFile, err := os.OpenFile(curFilePath, os.O_RDONLY|os.O_CREATE, autoFilePerms) if err != nil { return err } curReader := bufio.NewReader(curFile) // Update gr.cur* if gr.curFile != nil { gr.curFile.Close() // TODO return error? } gr.curIndex = index gr.curFile = curFile gr.curReader = curReader gr.curLine = nil return nil } // CurIndex returns cursor's file index. func (gr *GroupReader) CurIndex() int { gr.mtx.Lock() defer gr.mtx.Unlock() return gr.curIndex } // SetIndex sets the cursor's file index to index by opening a file at this // position. func (gr *GroupReader) SetIndex(index int) error { gr.mtx.Lock() defer gr.mtx.Unlock() return gr.openFile(index) }