Golang AllocDirFS.List方法代码示例

// blockUntilNextLog returns a channel that will have data sent when the next
// log index or anything greater is created.
func blockUntilNextLog(fs allocdir.AllocDirFS, t *tomb.Tomb, logPath, task, logType string, nextIndex int64) chan error {
	nextPath := filepath.Join(logPath, fmt.Sprintf("%s.%s.%d", task, logType, nextIndex))
	next := make(chan error, 1)

	go func() {
		eofCancelCh, err := fs.BlockUntilExists(nextPath, t)
		if err != nil {
			next <- err
			close(next)
			return
		}

		ticker := time.NewTicker(nextLogCheckRate)
		defer ticker.Stop()
		scanCh := ticker.C
		for {
			select {
			case <-t.Dead():
				next <- fmt.Errorf("shutdown triggered")
				close(next)
				return
			case err := <-eofCancelCh:
				next <- err
				close(next)
				return
			case <-scanCh:
				entries, err := fs.List(logPath)
				if err != nil {
					next <- fmt.Errorf("failed to list entries: %v", err)
					close(next)
					return
				}

				indexes, err := logIndexes(entries, task, logType)
				if err != nil {
					next <- err
					close(next)
					return
				}

				// Scan and see if there are any entries larger than what we are
				// waiting for.
				for _, entry := range indexes {
					if entry.idx >= nextIndex {
						next <- nil
						close(next)
						return
					}
				}
			}
		}
	}()

	return next
}

func (s *HTTPServer) logs(follow bool, offset int64,
	origin, task, logType string,
	fs allocdir.AllocDirFS, output io.WriteCloser) error {

	// Create the framer
	framer := NewStreamFramer(output, streamHeartbeatRate, streamBatchWindow, streamFrameSize)
	framer.Run()
	defer framer.Destroy()

	// Path to the logs
	logPath := filepath.Join(allocdir.SharedAllocName, allocdir.LogDirName)

	// nextIdx is the next index to read logs from
	var nextIdx int64
	switch origin {
	case "start":
		nextIdx = 0
	case "end":
		nextIdx = math.MaxInt64
		offset *= -1
	default:
		return invalidOrigin
	}

	// Create a tomb to cancel watch events
	t := tomb.Tomb{}
	defer func() {
		t.Kill(nil)
		t.Done()
	}()

	for {
		// Logic for picking next file is:
		// 1) List log files
		// 2) Pick log file closest to desired index
		// 3) Open log file at correct offset
		// 3a) No error, read contents
		// 3b) If file doesn't exist, goto 1 as it may have been rotated out
		entries, err := fs.List(logPath)
		if err != nil {
			return fmt.Errorf("failed to list entries: %v", err)
		}

		// If we are not following logs, determine the max index for the logs we are
		// interested in so we can stop there.
		maxIndex := int64(math.MaxInt64)
		if !follow {
			_, idx, _, err := findClosest(entries, maxIndex, 0, task, logType)
			if err != nil {
				return err
			}
			maxIndex = idx
		}

		logEntry, idx, openOffset, err := findClosest(entries, nextIdx, offset, task, logType)
		if err != nil {
			return err
		}

		var eofCancelCh chan error
		exitAfter := false
		if !follow && idx > maxIndex {
			// Exceeded what was there initially so return
			return nil
		} else if !follow && idx == maxIndex {
			// At the end
			eofCancelCh = make(chan error)
			close(eofCancelCh)
			exitAfter = true
		} else {
			eofCancelCh = blockUntilNextLog(fs, &t, logPath, task, logType, idx+1)
		}

		p := filepath.Join(logPath, logEntry.Name)
		err = s.stream(openOffset, p, fs, framer, eofCancelCh)

		if err != nil {
			// Check if there was an error where the file does not exist. That means
			// it got rotated out from under us.
			if os.IsNotExist(err) {
				continue
			}

			// Check if the connection was closed
			if err == syscall.EPIPE {
				return nil
			}

			return fmt.Errorf("failed to stream %q: %v", p, err)
		}

		if exitAfter {
			return nil
		}

		//Since we successfully streamed, update the overall offset/idx.
		offset = int64(0)
		nextIdx = idx + 1
	}

//.........这里部分代码省略.........