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fix forking task runner task shutdown to be more graceful #8085

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Merged
clintropolis merged 2 commits into from
Jul 23, 2019
Merged

fix forking task runner task shutdown to be more graceful #8085

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fix forking task runner shutdown to be more graceful
clintropolis Jul 15, 2019
5429a57
javadoc
clintropolis Jul 15, 2019
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42 changes: 25 additions & 17 deletions indexing-service/src/main/java/org/apache/druid/indexing/overlord/ForkingTaskRunner.java
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Original file line number Diff line number Diff line change
Expand Up @@ -527,16 +527,7 @@ public void stop()

synchronized (tasks) {
for (ForkingTaskRunnerWorkItem taskWorkItem : tasks.values()) {
if (taskWorkItem.processHolder != null) {
log.info("Closing output stream to task[%s].", taskWorkItem.getTask().getId());
try {
taskWorkItem.processHolder.process.getOutputStream().close();
}
catch (Exception e) {
log.warn(e, "Failed to close stdout to task[%s]. Destroying task.", taskWorkItem.getTask().getId());
taskWorkItem.processHolder.process.destroy();
}
}
shutdownTaskProcess(taskWorkItem);
}
}

Expand Down Expand Up @@ -593,12 +584,8 @@ public void shutdown(final String taskid, String reason)
}

taskInfo.shutdown = true;
}

if (taskInfo.processHolder != null) {
// Will trigger normal failure mechanisms due to process exit
log.info("Killing process for task: %s", taskid);
taskInfo.processHolder.process.destroy();
shutdownTaskProcess(taskInfo);
}
}

Expand Down Expand Up @@ -694,8 +681,10 @@ public InputStream openStream() throws IOException
);
}

// Save running tasks to a file, so they can potentially be restored on next startup. Suppresses exceptions that
// occur while saving.
/**
* Save running tasks to a file, so they can potentially be restored on next startup. Suppresses exceptions that occur
* while saving.
*/
@GuardedBy("tasks")
private void saveRunningTasks()
{
Expand All @@ -714,6 +703,25 @@ private void saveRunningTasks()
}
}

/**
* Close task output stream (input stream of process) sending EOF telling process to terminate, destroying the process
* if an exception is encountered.
*/
private void shutdownTaskProcess(ForkingTaskRunnerWorkItem taskInfo)
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@jihoonson jihoonson Jul 15, 2019 •
edited
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Would you add a comment like "this method triggers lifecycle.stop()"?

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@clintropolis clintropolis Jul 15, 2019

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It sort of seems like a misleading comment, since it doesn't call that directly, it's just closing the stream of the forked task and destroying it if that encounters an exception. Also since I am not entirely sure that lifecycle stop wasn't being called previously...

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@clintropolis clintropolis Jul 15, 2019

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That said, I agree it probably needs some sort of javadoc/comment, i'll see what I can come up with

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@clintropolis clintropolis Jul 15, 2019

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added javadoc

{
if (taskInfo.processHolder != null) {
// Will trigger normal failure mechanisms due to process exit
log.info("Closing output stream to task[%s].", taskInfo.getTask().getId());
try {
taskInfo.processHolder.process.getOutputStream().close();
}
catch (Exception e) {
log.warn(e, "Failed to close stdout to task[%s]. Destroying task.", taskInfo.getTask().getId());
taskInfo.processHolder.process.destroy();
}
}
}

private File getRestoreFile()
{
return new File(taskConfig.getBaseTaskDir(), TASK_RESTORE_FILENAME);
Expand Down