[FLUME-2811] Taildir source doesn't call stop() on graceful shutdown

• Type: Bug
• Status: Open
• Priority: Critical
• Resolution: Unresolved
• Affects Version/s: 1.7.0
• Component/s: Sinks+Sources
• Labels: newbie
• Assignee: Umesh Chaudhary
• Reporter: Jun Seok Hong
• Created: 14/Oct/15 06:26
• Updated: 17/Sep/22 17:20

Description

Taildir source doesn't call stop() on graceful shutdown.

Test configuration.
source - taildir
channel - PseudoTxnMemoryChannel / flume-kafka-channel
sink - none

I found that flume sometimes doesn't terminate with Taildir source.
I had to kill the process to terminate it.

tailFileProcess() function in TaildirSource.java has a infinite loop.

When the process interrupted, ChannelException will happen, but it can't breaks the infinite loop.
I think that's the reason why Taildir can't call stop() function.

TaildirSource.java

 private void tailFileProcess(TailFile tf, boolean backoffWithoutNL)
      throws IOException, InterruptedException {
    while (true) {
      reader.setCurrentFile(tf);
      List<Event> events = reader.readEvents(batchSize, backoffWithoutNL);
      if (events.isEmpty()) {
        break;
      }
      sourceCounter.addToEventReceivedCount(events.size());
      sourceCounter.incrementAppendBatchReceivedCount();
      try {
        getChannelProcessor().processEventBatch(events);
        reader.commit();
      } catch (ChannelException ex) {
        logger.warn("The channel is full or unexpected failure. " +
          "The source will try again after " + retryInterval + " ms");
        TimeUnit.MILLISECONDS.sleep(retryInterval);
        retryInterval = retryInterval << 1;
        retryInterval = Math.min(retryInterval, maxRetryInterval);
        continue;
      }
      retryInterval = 1000;
      sourceCounter.addToEventAcceptedCount(events.size());
      sourceCounter.incrementAppendBatchAcceptedCount();
      if (events.size() < batchSize) {
        break;
      }
    }
  }