diff --git a/Doc/library/test.rst b/Doc/library/test.rst index 5c458bf3ec2f26..e255952d4570ef 100644 --- a/Doc/library/test.rst +++ b/Doc/library/test.rst @@ -413,6 +413,51 @@ The :mod:`test.support` module defines the following constants: The :mod:`test.support` module defines the following functions: +.. function:: busy_retry(timeout, err_msg=None, /, *, error=True) + + Run the loop body until ``break`` stops the loop. + + After *timeout* seconds, raise an :exc:`AssertionError` if *error* is true, + or just stop the loop if *error* is false. + + Example:: + + for _ in support.busy_retry(support.SHORT_TIMEOUT): + if check(): + break + + Example of error=False usage:: + + for _ in support.busy_retry(support.SHORT_TIMEOUT, error=False): + if check(): + break + else: + raise RuntimeError('my custom error') + +.. function:: sleeping_retry(timeout, err_msg=None, /, *, init_delay=0.010, max_delay=1.0, error=True) + + Wait strategy that applies exponential backoff. + + Run the loop body until ``break`` stops the loop. Sleep at each loop + iteration, but not at the first iteration. The sleep delay is doubled at + each iteration (up to *max_delay* seconds). + + See :func:`busy_retry` documentation for the parameters usage. + + Example raising an exception after SHORT_TIMEOUT seconds:: + + for _ in support.sleeping_retry(support.SHORT_TIMEOUT): + if check(): + break + + Example of error=False usage:: + + for _ in support.sleeping_retry(support.SHORT_TIMEOUT, error=False): + if check(): + break + else: + raise RuntimeError('my custom error') + .. function:: is_resource_enabled(resource) Return ``True`` if *resource* is enabled and available. The list of diff --git a/Lib/test/_test_multiprocessing.py b/Lib/test/_test_multiprocessing.py index 4a588d96deb943..dca5a19d2ed620 100644 --- a/Lib/test/_test_multiprocessing.py +++ b/Lib/test/_test_multiprocessing.py @@ -4313,18 +4313,13 @@ def test_shared_memory_cleaned_after_process_termination(self): p.terminate() p.wait() - deadline = time.monotonic() + support.LONG_TIMEOUT - t = 0.1 - while time.monotonic() < deadline: - time.sleep(t) - t = min(t*2, 5) + err_msg = ("A SharedMemory segment was leaked after " + "a process was abruptly terminated") + for _ in support.sleeping_retry(support.LONG_TIMEOUT, err_msg): try: smm = shared_memory.SharedMemory(name, create=False) except FileNotFoundError: break - else: - raise AssertionError("A SharedMemory segment was leaked after" - " a process was abruptly terminated.") if os.name == 'posix': # Without this line it was raising warnings like: @@ -5334,9 +5329,10 @@ def create_and_register_resource(rtype): p.terminate() p.wait() - deadline = time.monotonic() + support.LONG_TIMEOUT - while time.monotonic() < deadline: - time.sleep(.5) + err_msg = (f"A {rtype} resource was leaked after a process was " + f"abruptly terminated") + for _ in support.sleeping_retry(support.SHORT_TIMEOUT, + err_msg): try: _resource_unlink(name2, rtype) except OSError as e: @@ -5344,10 +5340,7 @@ def create_and_register_resource(rtype): # EINVAL self.assertIn(e.errno, (errno.ENOENT, errno.EINVAL)) break - else: - raise AssertionError( - f"A {rtype} resource was leaked after a process was " - f"abruptly terminated.") + err = p.stderr.read().decode('utf-8') p.stderr.close() expected = ('resource_tracker: There appear to be 2 leaked {} ' @@ -5575,18 +5568,17 @@ def wait_proc_exit(self): # but this can take a bit on slow machines, so wait a few seconds # if there are other children too (see #17395). join_process(self.proc) + start_time = time.monotonic() - t = 0.01 - while len(multiprocessing.active_children()) > 1: - time.sleep(t) - t *= 2 - dt = time.monotonic() - start_time - if dt >= 5.0: - test.support.environment_altered = True - support.print_warning(f"multiprocessing.Manager still has " - f"{multiprocessing.active_children()} " - f"active children after {dt} seconds") + for _ in support.sleeping_retry(5.0, error=False): + if len(multiprocessing.active_children()) <= 1: break + else: + dt = time.monotonic() - start_time + support.environment_altered = True + support.print_warning(f"multiprocessing.Manager still has " + f"{multiprocessing.active_children()} " + f"active children after {dt:.1f} seconds") def run_worker(self, worker, obj): self.proc = multiprocessing.Process(target=worker, args=(obj, )) @@ -5884,17 +5876,15 @@ def tearDownClass(cls): # but this can take a bit on slow machines, so wait a few seconds # if there are other children too (see #17395) start_time = time.monotonic() - t = 0.01 - while len(multiprocessing.active_children()) > 1: - time.sleep(t) - t *= 2 - dt = time.monotonic() - start_time - if dt >= 5.0: - test.support.environment_altered = True - support.print_warning(f"multiprocessing.Manager still has " - f"{multiprocessing.active_children()} " - f"active children after {dt} seconds") + for _ in support.sleeping_retry(5.0, error=False): + if len(multiprocessing.active_children()) <= 1: break + else: + dt = time.monotonic() - start_time + support.environment_altered = True + support.print_warning(f"multiprocessing.Manager still has " + f"{multiprocessing.active_children()} " + f"active children after {dt:.1f} seconds") gc.collect() # do garbage collection if cls.manager._number_of_objects() != 0: diff --git a/Lib/test/fork_wait.py b/Lib/test/fork_wait.py index 4d3dbd8e83f5a9..c565f593559483 100644 --- a/Lib/test/fork_wait.py +++ b/Lib/test/fork_wait.py @@ -54,10 +54,8 @@ def test_wait(self): self.threads.append(thread) # busy-loop to wait for threads - deadline = time.monotonic() + support.SHORT_TIMEOUT - while len(self.alive) < NUM_THREADS: - time.sleep(0.1) - if deadline < time.monotonic(): + for _ in support.sleeping_retry(support.SHORT_TIMEOUT, error=False): + if len(self.alive) >= NUM_THREADS: break a = sorted(self.alive.keys()) diff --git a/Lib/test/support/__init__.py b/Lib/test/support/__init__.py index 4baaeb766317f1..a62e8b4ec4f6b7 100644 --- a/Lib/test/support/__init__.py +++ b/Lib/test/support/__init__.py @@ -2250,3 +2250,79 @@ def atfork_func(): pass atfork_func.reference = ref_cycle os.register_at_fork(before=atfork_func) + + +def busy_retry(timeout, err_msg=None, /, *, error=True): + """ + Run the loop body until "break" stops the loop. + + After *timeout* seconds, raise an AssertionError if *error* is true, + or just stop if *error is false. + + Example: + + for _ in support.busy_retry(support.SHORT_TIMEOUT): + if check(): + break + + Example of error=False usage: + + for _ in support.busy_retry(support.SHORT_TIMEOUT, error=False): + if check(): + break + else: + raise RuntimeError('my custom error') + + """ + if timeout <= 0: + raise ValueError("timeout must be greater than zero") + + start_time = time.monotonic() + deadline = start_time + timeout + + while True: + yield + + if time.monotonic() >= deadline: + break + + if error: + dt = time.monotonic() - start_time + msg = f"timeout ({dt:.1f} seconds)" + if err_msg: + msg = f"{msg}: {err_msg}" + raise AssertionError(msg) + + +def sleeping_retry(timeout, err_msg=None, /, + *, init_delay=0.010, max_delay=1.0, error=True): + """ + Wait strategy that applies exponential backoff. + + Run the loop body until "break" stops the loop. Sleep at each loop + iteration, but not at the first iteration. The sleep delay is doubled at + each iteration (up to *max_delay* seconds). + + See busy_retry() documentation for the parameters usage. + + Example raising an exception after SHORT_TIMEOUT seconds: + + for _ in support.sleeping_retry(support.SHORT_TIMEOUT): + if check(): + break + + Example of error=False usage: + + for _ in support.sleeping_retry(support.SHORT_TIMEOUT, error=False): + if check(): + break + else: + raise RuntimeError('my custom error') + """ + + delay = init_delay + for _ in busy_retry(timeout, err_msg, error=error): + yield + + time.sleep(delay) + delay = min(delay * 2, max_delay) diff --git a/Lib/test/test__xxsubinterpreters.py b/Lib/test/test__xxsubinterpreters.py index 5d0ed9ea14ac7f..f20aae8e21c66f 100644 --- a/Lib/test/test__xxsubinterpreters.py +++ b/Lib/test/test__xxsubinterpreters.py @@ -45,12 +45,11 @@ def _wait_for_interp_to_run(interp, timeout=None): # run subinterpreter eariler than the main thread in multiprocess. if timeout is None: timeout = support.SHORT_TIMEOUT - start_time = time.monotonic() - deadline = start_time + timeout - while not interpreters.is_running(interp): - if time.monotonic() > deadline: - raise RuntimeError('interp is not running') - time.sleep(0.010) + for _ in support.sleeping_retry(timeout, error=False): + if interpreters.is_running(interp): + break + else: + raise RuntimeError('interp is not running') @contextlib.contextmanager diff --git a/Lib/test/test_concurrent_futures.py b/Lib/test/test_concurrent_futures.py index 6f3b4609232bbb..c12165366bb251 100644 --- a/Lib/test/test_concurrent_futures.py +++ b/Lib/test/test_concurrent_futures.py @@ -256,12 +256,12 @@ def test_initializer(self): else: with self.assertRaises(BrokenExecutor): future.result() + # At some point, the executor should break - t1 = time.monotonic() - while not self.executor._broken: - if time.monotonic() - t1 > 5: - self.fail("executor not broken after 5 s.") - time.sleep(0.01) + for _ in support.sleeping_retry(5, "executor not broken"): + if self.executor._broken: + break + # ... and from this point submit() is guaranteed to fail with self.assertRaises(BrokenExecutor): self.executor.submit(get_init_status) diff --git a/Lib/test/test_multiprocessing_main_handling.py b/Lib/test/test_multiprocessing_main_handling.py index 510d8d3a7597e1..35e9cd64fa6c01 100644 --- a/Lib/test/test_multiprocessing_main_handling.py +++ b/Lib/test/test_multiprocessing_main_handling.py @@ -40,6 +40,7 @@ import sys import time from multiprocessing import Pool, set_start_method +from test import support # We use this __main__ defined function in the map call below in order to # check that multiprocessing in correctly running the unguarded @@ -59,13 +60,11 @@ def f(x): results = [] with Pool(5) as pool: pool.map_async(f, [1, 2, 3], callback=results.extend) - start_time = time.monotonic() - while not results: - time.sleep(0.05) - # up to 1 min to report the results - dt = time.monotonic() - start_time - if dt > 60.0: - raise RuntimeError("Timed out waiting for results (%.1f sec)" % dt) + + # up to 1 min to report the results + for _ in support.sleeping_retry(60, "Timed out waiting for results"): + if results: + break results.sort() print(start_method, "->", results) @@ -86,19 +85,17 @@ def f(x): import sys import time from multiprocessing import Pool, set_start_method +from test import support start_method = sys.argv[1] set_start_method(start_method) results = [] with Pool(5) as pool: pool.map_async(int, [1, 4, 9], callback=results.extend) - start_time = time.monotonic() - while not results: - time.sleep(0.05) - # up to 1 min to report the results - dt = time.monotonic() - start_time - if dt > 60.0: - raise RuntimeError("Timed out waiting for results (%.1f sec)" % dt) + # up to 1 min to report the results + for _ in support.sleeping_retry(60, "Timed out waiting for results"): + if results: + break results.sort() print(start_method, "->", results) diff --git a/Lib/test/test_signal.py b/Lib/test/test_signal.py index 6aa529b0620001..a1d074a56cf656 100644 --- a/Lib/test/test_signal.py +++ b/Lib/test/test_signal.py @@ -812,13 +812,14 @@ def test_itimer_virtual(self): signal.signal(signal.SIGVTALRM, self.sig_vtalrm) signal.setitimer(self.itimer, 0.3, 0.2) - start_time = time.monotonic() - while time.monotonic() - start_time < 60.0: + for _ in support.busy_retry(60.0, error=False): # use up some virtual time by doing real work _ = pow(12345, 67890, 10000019) if signal.getitimer(self.itimer) == (0.0, 0.0): - break # sig_vtalrm handler stopped this itimer - else: # Issue 8424 + # sig_vtalrm handler stopped this itimer + break + else: + # bpo-8424 self.skipTest("timeout: likely cause: machine too slow or load too " "high") @@ -832,13 +833,14 @@ def test_itimer_prof(self): signal.signal(signal.SIGPROF, self.sig_prof) signal.setitimer(self.itimer, 0.2, 0.2) - start_time = time.monotonic() - while time.monotonic() - start_time < 60.0: + for _ in support.busy_retry(60.0, error=False): # do some work _ = pow(12345, 67890, 10000019) if signal.getitimer(self.itimer) == (0.0, 0.0): - break # sig_prof handler stopped this itimer - else: # Issue 8424 + # sig_prof handler stopped this itimer + break + else: + # bpo-8424 self.skipTest("timeout: likely cause: machine too slow or load too " "high") @@ -1307,8 +1309,6 @@ def handler(signum, frame): self.setsig(signal.SIGALRM, handler) # for ITIMER_REAL expected_sigs = 0 - deadline = time.monotonic() + support.SHORT_TIMEOUT - while expected_sigs < N: # Hopefully the SIGALRM will be received somewhere during # initial processing of SIGUSR1. @@ -1317,8 +1317,9 @@ def handler(signum, frame): expected_sigs += 2 # Wait for handlers to run to avoid signal coalescing - while len(sigs) < expected_sigs and time.monotonic() < deadline: - time.sleep(1e-5) + for _ in support.sleeping_retry(support.SHORT_TIMEOUT, error=False): + if len(sigs) >= expected_sigs: + break # All ITIMER_REAL signals should have been delivered to the # Python handler diff --git a/Lib/test/test_ssl.py b/Lib/test/test_ssl.py index 6a66c167933de6..3acafbdaa6ee4b 100644 --- a/Lib/test/test_ssl.py +++ b/Lib/test/test_ssl.py @@ -2262,11 +2262,8 @@ def ssl_io_loop(self, sock, incoming, outgoing, func, *args, **kwargs): # A simple IO loop. Call func(*args) depending on the error we get # (WANT_READ or WANT_WRITE) move data between the socket and the BIOs. timeout = kwargs.get('timeout', support.SHORT_TIMEOUT) - deadline = time.monotonic() + timeout count = 0 - while True: - if time.monotonic() > deadline: - self.fail("timeout") + for _ in support.busy_retry(timeout): errno = None count += 1 try: diff --git a/Lib/test/test_support.py b/Lib/test/test_support.py index 23bcceedd71b2a..7738ca5e9b433d 100644 --- a/Lib/test/test_support.py +++ b/Lib/test/test_support.py @@ -9,7 +9,6 @@ import sys import tempfile import textwrap -import time import unittest import warnings @@ -461,18 +460,12 @@ def test_reap_children(self): # child process: do nothing, just exit os._exit(0) - t0 = time.monotonic() - deadline = time.monotonic() + support.SHORT_TIMEOUT - was_altered = support.environment_altered try: support.environment_altered = False stderr = io.StringIO() - while True: - if time.monotonic() > deadline: - self.fail("timeout") - + for _ in support.sleeping_retry(support.SHORT_TIMEOUT): with support.swap_attr(support.print_warning, 'orig_stderr', stderr): support.reap_children() @@ -481,9 +474,6 @@ def test_reap_children(self): if support.environment_altered: break - # loop until the child process completed - time.sleep(0.100) - msg = "Warning -- reap_children() reaped child process %s" % pid self.assertIn(msg, stderr.getvalue()) self.assertTrue(support.environment_altered) diff --git a/Lib/test/test_wait3.py b/Lib/test/test_wait3.py index 4ec7690ac19bbf..15d66ae825abf5 100644 --- a/Lib/test/test_wait3.py +++ b/Lib/test/test_wait3.py @@ -4,7 +4,6 @@ import os import subprocess import sys -import time import unittest from test.fork_wait import ForkWait from test import support @@ -20,14 +19,12 @@ def wait_impl(self, cpid, *, exitcode): # This many iterations can be required, since some previously run # tests (e.g. test_ctypes) could have spawned a lot of children # very quickly. - deadline = time.monotonic() + support.SHORT_TIMEOUT - while time.monotonic() <= deadline: + for _ in support.sleeping_retry(support.SHORT_TIMEOUT, error=False): # wait3() shouldn't hang, but some of the buildbots seem to hang # in the forking tests. This is an attempt to fix the problem. spid, status, rusage = os.wait3(os.WNOHANG) if spid == cpid: break - time.sleep(0.1) self.assertEqual(spid, cpid) self.assertEqual(os.waitstatus_to_exitcode(status), exitcode) diff --git a/Lib/test/test_wait4.py b/Lib/test/test_wait4.py index 24f1aaec60c56b..f66c0db1c20e6e 100644 --- a/Lib/test/test_wait4.py +++ b/Lib/test/test_wait4.py @@ -2,7 +2,6 @@ """ import os -import time import sys import unittest from test.fork_wait import ForkWait @@ -22,14 +21,12 @@ def wait_impl(self, cpid, *, exitcode): # Issue #11185: wait4 is broken on AIX and will always return 0 # with WNOHANG. option = 0 - deadline = time.monotonic() + support.SHORT_TIMEOUT - while time.monotonic() <= deadline: + for _ in support.sleeping_retry(support.SHORT_TIMEOUT, error=False): # wait4() shouldn't hang, but some of the buildbots seem to hang # in the forking tests. This is an attempt to fix the problem. spid, status, rusage = os.wait4(cpid, option) if spid == cpid: break - time.sleep(0.1) self.assertEqual(spid, cpid) self.assertEqual(os.waitstatus_to_exitcode(status), exitcode) self.assertTrue(rusage)
Note: This service is not intended for secure transactions such as banking, social media, email, or purchasing. Use at your own risk. We assume no liability whatsoever for broken pages.
Alternative Proxies: