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Differential D1459

workers: handling exceptions in windows workers
ClosedPublic

Authored by wlis on Nov 20 2017, 1:37 PM.

Details

Reviewers
durin42
Group Reviewers
hg-reviewers
Commits
rHG71427ff1dff8: workers: handling exceptions in windows workers
Summary

This adds handling of exceptions from worker threads and resurfaces them as if the function ran without workers.
If any of the threads throws, the main thread kills all running threads giving them 5 sec to handle the interruption and raises the first exception received.

We don't have to join threads if is_alive() is false

Test Plan

Ran multiple updates/enable/disable sparse profile and things worked well

Ran test on CentOS- all tests passing on @ passed here

Added a forged exception into the worker code and got it properly resurfaced and the rest of workers killed: P58642088
PS C:\open\<repo>> ..\facebook-hg-rpms\build\hg\hg.exe --config extensions.fsmonitor=! sparse --enable-profile <profile>
updating [==> ] 1300/39166 1m57sException in thread Thread-3:
Traceback (most recent call last):

File "C:\open\facebook-hg-rpms\build\hg\hg-python\lib\threading.py", line 801, in __bootstrap_inner
  self.run()
File "C:\open\facebook-hg-rpms\build\hg\mercurial\worker.py", line 244, in run
  raise e

Exception: Forged exception

Exception in thread Thread-2:
Traceback (most recent call last):

File "C:\open\facebook-hg-rpms\build\hg\hg-python\lib\threading.py", line 801, in __bootstrap_inner
  self.run()
File "C:\open\facebook-hg-rpms\build\hg\mercurial\worker.py", line 244, in run
  raise e

Exception: Forged exception
<...>
Traceback (most recent call last):

File "C:\open\facebook-hg-rpms\build\hg\hgexe.py", line 41, in <module>
  dispatch.run()
File "C:\open\facebook-hg-rpms\build\hg\mercurial\dispatch.py", line 85, in run
  status = (dispatch(req) or 0) & 255
File "C:\open\facebook-hg-rpms\build\hg\mercurial\dispatch.py", line 173, in dispatch
  ret = _runcatch(req)
File "C:\open\facebook-hg-rpms\build\hg\mercurial\dispatch.py", line 324, in _runcatch
  return _callcatch(ui, _runcatchfunc)
File "C:\open\facebook-hg-rpms\build\hg\mercurial\dispatch.py", line 332, in _callcatch
  return scmutil.callcatch(ui, func)
File "C:\open\facebook-hg-rpms\build\hg\mercurial\scmutil.py", line 154, in callcatch
  return func()
File "C:\open\facebook-hg-rpms\build\hg\mercurial\dispatch.py", line 314, in _runcatchfunc
  return _dispatch(req)
File "C:\open\facebook-hg-rpms\build\hg\mercurial\dispatch.py", line 951, in _dispatch
  cmdpats, cmdoptions)
File "C:\open\facebook-hg-rpms\build\hg\hg-python\lib\site-packages\remotefilelog\__init__.py", line 415, in runcommand
  return orig(lui, repo, *args, **kwargs)
File "C:\open\facebook-hg-rpms\build\hg\hg-python\lib\site-packages\hgext3rd\undo.py", line 118, in _runcommandwrapper
  result = orig(lui, repo, cmd, fullargs, *args)
File "C:\open\facebook-hg-rpms\build\hg\hgext\journal.py", line 84, in runcommand
  return orig(lui, repo, cmd, fullargs, *args)
File "C:\open\facebook-hg-rpms\build\hg\hg-python\lib\site-packages\hgext3rd\perftweaks.py", line 268, in _tracksparseprofiles
  res = runcommand(lui, repo, *args)
File "C:\open\facebook-hg-rpms\build\hg\hg-python\lib\site-packages\hgext3rd\perftweaks.py", line 256, in _trackdirstatesizes
  res = runcommand(lui, repo, *args)
File "C:\open\facebook-hg-rpms\build\hg\hg-python\lib\site-packages\hgext3rd\copytrace.py", line 144, in _runcommand
  return orig(lui, repo, cmd, fullargs, ui, *args, **kwargs)
File "C:\open\facebook-hg-rpms\build\hg\hg-python\lib\site-packages\hgext3rd\fbamend\hiddenoverride.py", line 119, in runcommand
  result = orig(lui, repo, cmd, fullargs, *args)
File "C:\open\facebook-hg-rpms\build\hg\mercurial\dispatch.py", line 712, in runcommand
  ret = _runcommand(ui, options, cmd, d)
File "C:\open\facebook-hg-rpms\build\hg\mercurial\dispatch.py", line 959, in _runcommand
  return cmdfunc()
File "C:\open\facebook-hg-rpms\build\hg\mercurial\dispatch.py", line 948, in <lambda>
  d = lambda: util.checksignature(func)(ui, *args, **strcmdopt)
File "C:\open\facebook-hg-rpms\build\hg\mercurial\util.py", line 1183, in check
  return func(*args, **kwargs)
File "C:\open\facebook-hg-rpms\build\hg\hg-python\lib\site-packages\hgext3rd\fbsparse.py", line 860, in sparse
  disableprofile=disableprofile, force=force)
File "C:\open\facebook-hg-rpms\build\hg\hg-python\lib\site-packages\hgext3rd\fbsparse.py", line 949, in _config
  len, _refresh(ui, repo, oldstatus, oldsparsematch, force))
File "C:\open\facebook-hg-rpms\build\hg\hg-python\lib\site-packages\hgext3rd\fbsparse.py", line 1116, in _refresh
  mergemod.applyupdates(repo, typeactions, repo[None], repo['.'], False)
File "C:\open\facebook-hg-rpms\build\hg\hg-python\lib\site-packages\remotefilelog\__init__.py", line 311, in applyupdates
  return orig(repo, actions, wctx, mctx, overwrite, labels=labels)
File "C:\open\facebook-hg-rpms\build\hg\mercurial\merge.py", line 1464, in applyupdates
  for i, item in prog:
File "C:\open\facebook-hg-rpms\build\hg\mercurial\worker.py", line 286, in _windowsworker
  raise t.exception

Exception: Forged exception
PS C:\open\ovrsource>

Diff Detail

Repository
rHG Mercurial
Lint
Automatic diff as part of commit; lint not applicable.
Unit
Automatic diff as part of commit; unit tests not applicable.

Event Timeline

wlis created this revision.Nov 20 2017, 1:37 PM
durin42 accepted this revision.Dec 5 2017, 5:27 PM
This revision is now accepted and ready to land.Dec 5 2017, 5:27 PM
Closed by commit rHG71427ff1dff8: workers: handling exceptions in windows workers (authored by wlis). · Explain WhyDec 15 2017, 12:13 PM
This revision was automatically updated to reflect the committed changes.

Revision Contents
Changeset List

PathPackages
Mmercurial/worker.py (63 lines)

Diff 4486

mercurial/worker.py

def __init__(self, taskqueue, resultqueue, func, staticargs, def __init__(self, taskqueue, resultqueue, func, staticargs,
group=None, target=None, name=None, verbose=None): group=None, target=None, name=None, verbose=None):
threading.Thread.__init__(self, group=group, target=target, threading.Thread.__init__(self, group=group, target=target,
name=name, verbose=verbose) name=name, verbose=verbose)
self._taskqueue = taskqueue self._taskqueue = taskqueue
self._resultqueue = resultqueue self._resultqueue = resultqueue
self._func = func self._func = func
self._staticargs = staticargs self._staticargs = staticargs
self._interrupted = False
self.exception = None
def interrupt(self):
self._interrupted = True
def run(self): def run(self):
try:
while not self._taskqueue.empty(): while not self._taskqueue.empty():
try: try:
args = self._taskqueue.get_nowait() args = self._taskqueue.get_nowait()
for res in self._func(*self._staticargs + (args,)): for res in self._func(*self._staticargs + (args,)):
self._resultqueue.put(res) self._resultqueue.put(res)
# threading doesn't provide a native way to
# interrupt execution. handle it manually at every
# iteration.
if self._interrupted:
return
except util.empty: except util.empty:
break break
except Exception as e:
# store the exception such that the main thread can resurface
# it as if the func was running without workers.
self.exception = e
raise
workers = _numworkers(ui)
threads = [] threads = []
def killworkers():
for t in threads:
t.interrupt()
for t in threads:
# try to let the threads handle interruption, but don't wait
# indefintely. the thread could be in infinite loop, handling
# a very long task or in a deadlock situation
t.join(5)
if t.is_alive():
raise error.Abort(_('failed to join worker thread'))
workers = _numworkers(ui)
resultqueue = util.queue() resultqueue = util.queue()
taskqueue = util.queue() taskqueue = util.queue()
# partition work to more pieces than workers to minimize the chance # partition work to more pieces than workers to minimize the chance
# of uneven distribution of large tasks between the workers # of uneven distribution of large tasks between the workers
for pargs in partition(args, workers * 20): for pargs in partition(args, workers * 20):
taskqueue.put(pargs) taskqueue.put(pargs)
for _i in range(workers): for _i in range(workers):
t = Worker(taskqueue, resultqueue, func, staticargs) t = Worker(taskqueue, resultqueue, func, staticargs)
threads.append(t) threads.append(t)
t.start() t.start()
while any(t.is_alive() for t in threads):
while len(threads) > 0:
while not resultqueue.empty(): while not resultqueue.empty():
yield resultqueue.get() yield resultqueue.get()
t = threads[0] threads[0].join(0.05)
t.join(0.05) finishedthreads = [_t for _t in threads if not _t.is_alive()]
if not t.is_alive(): for t in finishedthreads:
if t.exception is not None:
try:
killworkers()
except Exception:
# pass over the workers joining failure. it is more
# important to surface the inital exception than the
# fact that one of workers may be processing a large
# task and does not get to handle the interruption.
ui.warn(_("failed to kill worker threads while handling "
"an exception"))
raise t.exception
threads.remove(t) threads.remove(t)
while not resultqueue.empty(): while not resultqueue.empty():
yield resultqueue.get() yield resultqueue.get()
if pycompat.iswindows: if pycompat.iswindows:
_platformworker = _windowsworker _platformworker = _windowsworker
else: else:
_platformworker = _posixworker _platformworker = _posixworker