def test_shared_memory_SharedMemoryManager_basics(self):
smm1 = shared_memory.SharedMemoryManager()
with self.assertRaises(ValueError):
smm1.SharedMemory(
size=9) # Fails if SharedMemoryServer not started
smm1.start()
lol = [smm1.ShareableList(range(i)) for i in range(5, 10)]
lom = [smm1.SharedMemory(size=j) for j in range(32, 128, 16)]
doppleganger_list0 = shared_memory.ShareableList(name=lol[0].shm.name)
self.assertEqual(len(doppleganger_list0), 5)
doppleganger_shm0 = shared_memory.SharedMemory(name=lom[0].name)
self.assertGreaterEqual(len(doppleganger_shm0.buf), 32)
held_name = lom[0].name
smm1.shutdown()
if sys.platform != "win32":
# Calls to unlink() have no effect on Windows platform; shared
# memory will only be released once final process exits.
with self.assertRaises(FileNotFoundError):
# No longer there to be attached to again.
absent_shm = shared_memory.SharedMemory(name=held_name)
with shared_memory.SharedMemoryManager() as smm2:
sl = smm2.ShareableList("howdy")
shm = smm2.SharedMemory(size=128)
held_name = sl.shm.name
if sys.platform != "win32":
with self.assertRaises(FileNotFoundError):
# No longer there to be attached to again.
absent_sl = shared_memory.ShareableList(name=held_name)
def __init__(self, shape, dtype=np.float64, name=None):
"""Creates a new SharedNDArray.
If name is left blank, a new POSIX shared memory segment is created using a random name.
Args:
shape: Shape of the wrapped ndarray.
dtype: Data type of the wrapped ndarray.
name: Optional; the filesystem path of the underlying POSIX shared memory.
Returns:
A new SharedNDArray of the given shape and dtype and backed by the given optional name.
Raises:
SharedNDArrayError: if an error occurs.
"""
size = MINIMUMSHMSIZE + int(np.prod(shape)) * np.dtype(dtype).itemsize
if name:
try:
self._shm = shared_memory.SharedMemory(name, size=size)
except shared_memory.ExistentialError as ee:
raise ee.__class__(f"{ee.args[0]}; requested name: {name}")
else:
self._shm = shared_memory.SharedMemory(None,
flags=shared_memory.O_CREX,
size=size)
self.array = np.ndarray(shape, dtype, self._shm.buf, order='C')
def _attach_existing_shmem_then_write(shmem_name_or_obj, binary_data):
if isinstance(shmem_name_or_obj, str):
local_sms = shared_memory.SharedMemory(shmem_name_or_obj)
else:
local_sms = shmem_name_or_obj
local_sms.buf[:len(binary_data)] = binary_data
local_sms.close()
def test_shared_memory_across_processes(self):
# bpo-40135: don't define shared memory block's name in case of
# the failure when we run multiprocessing tests in parallel.
sms = shared_memory.SharedMemory(create=True, size=512)
self.addCleanup(sms.unlink)
# Verify remote attachment to existing block by name is working.
p = multiprocessing.Process(
target=self._attach_existing_shmem_then_write,
args=(sms.name, b'howdy'))
p.daemon = True
p.start()
p.join()
self.assertEqual(bytes(sms.buf[:5]), b'howdy')
# Verify pickling of SharedMemory instance also works.
p = multiprocessing.Process(
target=self._attach_existing_shmem_then_write,
args=(sms, b'HELLO'))
p.daemon = True
p.start()
p.join()
self.assertEqual(bytes(sms.buf[:5]), b'HELLO')
sms.close()
def test_shared_memory_cleaned_after_process_termination(self):
cmd = '''if 1:
import os, time, sys
import shared_memory
# Create a shared_memory segment, and send the segment name
sm = shared_memory.SharedMemory(create=True, size=10)
sys.stdout.write(sm.name + '\\n')
sys.stdout.flush()
time.sleep(100)
'''
with subprocess.Popen([sys.executable, '-E', '-c', cmd],
stdout=subprocess.PIPE,
stderr=subprocess.PIPE) as p:
name = p.stdout.readline().strip().decode()
# killing abruptly processes holding reference to a shared memory
# segment should not leak the given memory segment.
p.terminate()
p.wait()
deadline = time.monotonic() + 60
t = 0.1
while time.monotonic() < deadline:
time.sleep(t)
t = min(t * 2, 5)
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':
# A warning was emitted by the subprocess' own
# resource_tracker (on Windows, shared memory segments
# are released automatically by the OS).
err = p.stderr.read().decode()
self.assertIn(
"resource_tracker: There appear to be 1 leaked "
"shared_memory objects to clean up at shutdown", err)
def test_shared_memory_basics(self):
sms = shared_memory.SharedMemory('test01_tsmb', create=True, size=512)
self.addCleanup(sms.unlink)
# Verify attributes are readable.
self.assertEqual(sms.name, 'test01_tsmb')
self.assertGreaterEqual(sms.size, 512)
self.assertGreaterEqual(len(sms.buf), sms.size)
# Modify contents of shared memory segment through memoryview.
sms.buf[0] = 42
self.assertEqual(sms.buf[0], 42)
# Attach to existing shared memory segment.
also_sms = shared_memory.SharedMemory('test01_tsmb')
self.assertEqual(also_sms.buf[0], 42)
also_sms.close()
# Attach to existing shared memory segment but specify a new size.
same_sms = shared_memory.SharedMemory('test01_tsmb',
size=20 * sms.size)
self.assertLess(same_sms.size, 20 * sms.size) # Size was ignored.
same_sms.close()
if _USE_POSIX:
# Posix Shared Memory can only be unlinked once. Here we
# test an implementation detail that is not observed across
# all supported platforms (since WindowsNamedSharedMemory
# manages unlinking on its own and unlink() does nothing).
# True release of shared memory segment does not necessarily
# happen until process exits, depending on the OS platform.
with self.assertRaises(FileNotFoundError):
sms_uno = shared_memory.SharedMemory('test01_dblunlink',
create=True,
size=5000)
try:
self.assertGreaterEqual(sms_uno.size, 5000)
sms_duo = shared_memory.SharedMemory('test01_dblunlink')
sms_duo.unlink() # First shm_unlink() call.
sms_duo.close()
sms_uno.close()
finally:
sms_uno.unlink() # A second shm_unlink() call is bad.
with self.assertRaises(FileExistsError):
# Attempting to create a new shared memory segment with a
# name that is already in use triggers an exception.
there_can_only_be_one_sms = shared_memory.SharedMemory(
'test01_tsmb', create=True, size=512)
if _USE_POSIX:
# Requesting creation of a shared memory segment with the option
# to attach to an existing segment, if that name is currently in
# use, should not trigger an exception.
# Note: Using a smaller size could possibly cause truncation of
# the existing segment but is OS platform dependent. In the
# case of MacOS/darwin, requesting a smaller size is disallowed.
class OptionalAttachSharedMemory(shared_memory.SharedMemory):
_flags = os.O_CREAT | os.O_RDWR
ok_if_exists_sms = OptionalAttachSharedMemory('test01_tsmb')
self.assertEqual(ok_if_exists_sms.size, sms.size)
ok_if_exists_sms.close()
# Attempting to attach to an existing shared memory segment when
# no segment exists with the supplied name triggers an exception.
with self.assertRaises(FileNotFoundError):
nonexisting_sms = shared_memory.SharedMemory('test01_notthere')
nonexisting_sms.unlink() # Error should occur on prior line.
sms.close()
# Test creating a shared memory segment with negative size
with self.assertRaises(ValueError):
sms_invalid = shared_memory.SharedMemory(create=True, size=-1)
# Test creating a shared memory segment with size 0
with self.assertRaises(ValueError):
sms_invalid = shared_memory.SharedMemory(create=True, size=0)
# Test creating a shared memory segment without size argument
with self.assertRaises(ValueError):
sms_invalid = shared_memory.SharedMemory(create=True)