Mercurial > hg
view tests/test-util.py @ 39561:d06834e0f48e
wireprotov2peer: stream decoded responses
Previously, wire protocol version 2 would buffer all response data.
Only once all data was received did we CBOR decode it and resolve
the future associated with the command. This was obviously not
desirable. In future commits that introduce large response payloads,
this caused significant memory bloat and slowed down client
operations due to waiting on the server.
This commit refactors the response handling code so that response
data can be streamed.
Command response objects now contain a buffered CBOR decoder. As
new data arrives, it is fed into the decoder. Decoded objects are
made available to the generator as they are decoded.
Because there is a separate thread processing incoming frames and
feeding data into the response object, there is the potential for
race conditions when mutating response objects. So a lock has been
added to guard access to critical state variables.
Because the generator emitting decoded objects needs to wait on
those objects to become available, we've added an Event for the
generator to wait on so it doesn't busy loop. This does mean
there is the potential for deadlocks. And I'm pretty sure they can
occur in some scenarios. We already have a handful of TODOs around
this. But I've added some more. Fixing this will likely require
moving the background thread receiving frames into clienthandler.
We likely would have done this anyway when implementing the client
bits for the SSH transport.
Test output changes because the initial CBOR map holding the overall
response state is now always handled internally by the response
object.
Differential Revision: https://phab.mercurial-scm.org/D4474
author | Gregory Szorc <gregory.szorc@gmail.com> |
---|---|
date | Wed, 29 Aug 2018 15:17:11 -0700 |
parents | 331ab85e910b |
children | 2372284d9457 |
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# unit tests for mercuril.util utilities from __future__ import absolute_import import contextlib import itertools import unittest from mercurial import pycompat, util, utils @contextlib.contextmanager def mocktimer(incr=0.1, *additional_targets): """Replaces util.timer and additional_targets with a mock The timer starts at 0. On each call the time incremented by the value of incr. If incr is an iterable, then the time is incremented by the next value from that iterable, looping in a cycle when reaching the end. additional_targets must be a sequence of (object, attribute_name) tuples; the mock is set with setattr(object, attribute_name, mock). """ time = [0] try: incr = itertools.cycle(incr) except TypeError: incr = itertools.repeat(incr) def timer(): time[0] += next(incr) return time[0] # record original values orig = util.timer additional_origs = [(o, a, getattr(o, a)) for o, a in additional_targets] # mock out targets util.timer = timer for obj, attr in additional_targets: setattr(obj, attr, timer) try: yield finally: # restore originals util.timer = orig for args in additional_origs: setattr(*args) # attr.s default factory for util.timedstats.start binds the timer we # need to mock out. _start_default = (util.timedcmstats.start.default, 'factory') @contextlib.contextmanager def capturestderr(): """Replace utils.procutil.stderr with a pycompat.bytesio instance The instance is made available as the return value of __enter__. This contextmanager is reentrant. """ orig = utils.procutil.stderr utils.procutil.stderr = pycompat.bytesio() try: yield utils.procutil.stderr finally: utils.procutil.stderr = orig class timedtests(unittest.TestCase): def testtimedcmstatsstr(self): stats = util.timedcmstats() self.assertEqual(str(stats), '<unknown>') self.assertEqual(bytes(stats), b'<unknown>') stats.elapsed = 12.34 self.assertEqual(str(stats), pycompat.sysstr(util.timecount(12.34))) self.assertEqual(bytes(stats), util.timecount(12.34)) def testtimedcmcleanexit(self): # timestamps 1, 4, elapsed time of 4 - 1 = 3 with mocktimer([1, 3], _start_default): with util.timedcm('pass') as stats: # actual context doesn't matter pass self.assertEqual(stats.start, 1) self.assertEqual(stats.elapsed, 3) self.assertEqual(stats.level, 1) def testtimedcmnested(self): # timestamps 1, 3, 6, 10, elapsed times of 6 - 3 = 3 and 10 - 1 = 9 with mocktimer([1, 2, 3, 4], _start_default): with util.timedcm('outer') as outer_stats: with util.timedcm('inner') as inner_stats: # actual context doesn't matter pass self.assertEqual(outer_stats.start, 1) self.assertEqual(outer_stats.elapsed, 9) self.assertEqual(outer_stats.level, 1) self.assertEqual(inner_stats.start, 3) self.assertEqual(inner_stats.elapsed, 3) self.assertEqual(inner_stats.level, 2) def testtimedcmexception(self): # timestamps 1, 4, elapsed time of 4 - 1 = 3 with mocktimer([1, 3], _start_default): try: with util.timedcm('exceptional') as stats: raise ValueError() except ValueError: pass self.assertEqual(stats.start, 1) self.assertEqual(stats.elapsed, 3) self.assertEqual(stats.level, 1) def testtimeddecorator(self): @util.timed def testfunc(callcount=1): callcount -= 1 if callcount: testfunc(callcount) # timestamps 1, 2, 3, 4, elapsed time of 3 - 2 = 1 and 4 - 1 = 3 with mocktimer(1, _start_default): with capturestderr() as out: testfunc(2) self.assertEqual(out.getvalue(), ( b' testfunc: 1.000 s\n' b' testfunc: 3.000 s\n' )) if __name__ == '__main__': import silenttestrunner silenttestrunner.main(__name__)