https://github.com/python/cpython/commit/9211b3dabeacb92713ac3f5f0fa43bc7cf69afd8
commit: 9211b3dabeacb92713ac3f5f0fa43bc7cf69afd8
branch: main
author: Russell Keith-Magee <russ...@keith-magee.com>
committer: freakboy3742 <russ...@keith-magee.com>
date: 2025-02-28T07:33:10+08:00
summary:
gh-129200: Add locking to the iOS testbed startup sequence. (#130564)
Add a lock to ensure that only one iOS testbed per user can start at a time, so
that the simulator discovery process doesn't collide between instances.
files:
A Misc/NEWS.d/next/Tests/2025-02-26-15-10-16.gh-issue-129200.XH4TeC.rst
M Makefile.pre.in
M iOS/testbed/__main__.py
diff --git a/Makefile.pre.in b/Makefile.pre.in
index aafd13091e3555..7ac301c82678aa 100644
--- a/Makefile.pre.in
+++ b/Makefile.pre.in
@@ -2149,7 +2149,7 @@ testuniversal: all
# a full Xcode install that has an iPhone SE (3rd edition) simulator available.
# This must be run *after* a `make install` has completed the build. The
# `--with-framework-name` argument *cannot* be used when configuring the build.
-XCFOLDER:=iOSTestbed.$(MULTIARCH).$(shell date +%s)
+XCFOLDER:=iOSTestbed.$(MULTIARCH).$(shell date +%s).$$PPID
.PHONY: testios
testios:
@if test "$(MACHDEP)" != "ios"; then \
diff --git
a/Misc/NEWS.d/next/Tests/2025-02-26-15-10-16.gh-issue-129200.XH4TeC.rst
b/Misc/NEWS.d/next/Tests/2025-02-26-15-10-16.gh-issue-129200.XH4TeC.rst
new file mode 100644
index 00000000000000..7bcc754a74c0c1
--- /dev/null
+++ b/Misc/NEWS.d/next/Tests/2025-02-26-15-10-16.gh-issue-129200.XH4TeC.rst
@@ -0,0 +1,2 @@
+Multiple iOS testbed runners can now be started at the same time without
+introducing an ambiguity over simulator ownership.
diff --git a/iOS/testbed/__main__.py b/iOS/testbed/__main__.py
index d12a5ab065b517..b436c9af99d2c4 100644
--- a/iOS/testbed/__main__.py
+++ b/iOS/testbed/__main__.py
@@ -1,11 +1,14 @@
import argparse
import asyncio
+import fcntl
import json
+import os
import plistlib
import re
import shutil
import subprocess
import sys
+import tempfile
from contextlib import asynccontextmanager
from datetime import datetime
from pathlib import Path
@@ -36,6 +39,46 @@ class MySystemExit(Exception):
pass
+class SimulatorLock:
+ # An fcntl-based filesystem lock that can be used to ensure that
+ def __init__(self, timeout):
+ self.filename = Path(tempfile.gettempdir()) / "python-ios-testbed"
+ self.timeout = timeout
+
+ self.fd = None
+
+ async def acquire(self):
+ # Ensure the lockfile exists
+ self.filename.touch(exist_ok=True)
+
+ # Try `timeout` times to acquire the lock file, with a 1 second pause
+ # between each attempt. Report status every 10 seconds.
+ for i in range(0, self.timeout):
+ try:
+ fd = os.open(self.filename, os.O_RDWR | os.O_TRUNC, 0o644)
+ fcntl.flock(fd, fcntl.LOCK_EX | fcntl.LOCK_NB)
+ except OSError:
+ os.close(fd)
+ if i % 10 == 0:
+ print("... waiting", flush=True)
+ await asyncio.sleep(1)
+ else:
+ self.fd = fd
+ return
+
+ # If we reach the end of the loop, we've exceeded the allowed number of
+ # attempts.
+ raise ValueError("Unable to obtain lock on iOS simulator creation")
+
+ def release(self):
+ # If a lock is held, release it.
+ if self.fd is not None:
+ # Release the lock.
+ fcntl.flock(self.fd, fcntl.LOCK_UN)
+ os.close(self.fd)
+ self.fd = None
+
+
# All subprocesses are executed through this context manager so that no matter
# what happens, they can always be cancelled from another task, and they will
# always be cleaned up on exit.
@@ -107,7 +150,7 @@ async def list_devices():
raise
-async def find_device(initial_devices):
+async def find_device(initial_devices, lock):
while True:
new_devices = set(await list_devices()).difference(initial_devices)
if len(new_devices) == 0:
@@ -115,15 +158,16 @@ async def find_device(initial_devices):
elif len(new_devices) == 1:
udid = new_devices.pop()
print(f"{datetime.now():%Y-%m-%d %H:%M:%S}: New test simulator
detected")
- print(f"UDID: {udid}")
+ print(f"UDID: {udid}", flush=True)
+ lock.release()
return udid
else:
exit(f"Found more than one new device: {new_devices}")
-async def log_stream_task(initial_devices):
+async def log_stream_task(initial_devices, lock):
# Wait up to 5 minutes for the build to complete and the simulator to boot.
- udid = await asyncio.wait_for(find_device(initial_devices), 5 * 60)
+ udid = await asyncio.wait_for(find_device(initial_devices, lock), 5 * 60)
# Stream the iOS device's logs, filtering out messages that come from the
# XCTest test suite (catching NSLog messages from the test method), or
@@ -171,7 +215,7 @@ async def log_stream_task(initial_devices):
async def xcode_test(location, simulator, verbose):
# Run the test suite on the named simulator
- print("Starting xcodebuild...")
+ print("Starting xcodebuild...", flush=True)
args = [
"xcodebuild",
"test",
@@ -331,7 +375,17 @@ async def run_testbed(simulator: str, args: list[str],
verbose: bool=False):
location = Path(__file__).parent
print("Updating plist...", end="", flush=True)
update_plist(location, args)
- print(" done.")
+ print(" done.", flush=True)
+
+ # We need to get an exclusive lock on simulator creation, to avoid issues
+ # with multiple simulators starting and being unable to tell which
+ # simulator is due to which testbed instance. See
+ # https://github.com/python/cpython/issues/130294 for details. Wait up to
+ # 10 minutes for a simulator to boot.
+ print("Obtaining lock on simulator creation...", flush=True)
+ simulator_lock = SimulatorLock(timeout=10*60)
+ await simulator_lock.acquire()
+ print("Simulator lock acquired.", flush=True)
# Get the list of devices that are booted at the start of the test run.
# The simulator started by the test suite will be detected as the new
@@ -340,13 +394,15 @@ async def run_testbed(simulator: str, args: list[str],
verbose: bool=False):
try:
async with asyncio.TaskGroup() as tg:
- tg.create_task(log_stream_task(initial_devices))
+ tg.create_task(log_stream_task(initial_devices, simulator_lock))
tg.create_task(xcode_test(location, simulator=simulator,
verbose=verbose))
except* MySystemExit as e:
raise SystemExit(*e.exceptions[0].args) from None
except* subprocess.CalledProcessError as e:
# Extract it from the ExceptionGroup so it can be handled by `main`.
raise e.exceptions[0]
+ finally:
+ simulator_lock.release()
def main():
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