def test_transaction_with_context_manager(lock_path):
class TestContextManager(object):
def __enter__(self):
vals['entered'] = True
def __exit__(self, t, v, tb):
vals['exited'] = True
vals['exception'] = (t or v or tb)
def exit_fn(t, v, tb):
vals['exited_fn'] = True
vals['exception_fn'] = (t or v or tb)
lock = lk.Lock(lock_path)
vals = {'entered': False, 'exited': False, 'exited_fn': False,
'exception': False, 'exception_fn': False}
with lk.ReadTransaction(lock, TestContextManager, exit_fn):
pass
assert vals['entered']
assert vals['exited']
assert not vals['exception']
assert vals['exited_fn']
assert not vals['exception_fn']
vals = {'entered': False, 'exited': False, 'exited_fn': False,
'exception': False, 'exception_fn': False}
with lk.ReadTransaction(lock, TestContextManager):
pass
assert vals['entered']
assert vals['exited']
assert not vals['exception']
assert not vals['exited_fn']
assert not vals['exception_fn']
vals = {'entered': False, 'exited': False, 'exited_fn': False,
'exception': False, 'exception_fn': False}
with lk.WriteTransaction(lock, TestContextManager, exit_fn):
pass
assert vals['entered']
assert vals['exited']
assert not vals['exception']
assert vals['exited_fn']
assert not vals['exception_fn']
vals = {'entered': False, 'exited': False, 'exited_fn': False,
'exception': False, 'exception_fn': False}
with lk.WriteTransaction(lock, TestContextManager):
pass
assert vals['entered']
assert vals['exited']
assert not vals['exception']
assert not vals['exited_fn']
assert not vals['exception_fn']
def test_nested_write_transaction(lock_path):
"""Ensure that the outermost write transaction writes."""
def write(t, v, tb):
vals['wrote'] = True
vals = collections.defaultdict(lambda: False)
lock = AssertLock(lock_path, vals)
# write/write
with lk.WriteTransaction(lock, release=write):
assert not vals['wrote']
with lk.WriteTransaction(lock, release=write):
assert not vals['wrote']
assert not vals['wrote']
assert vals['wrote']
# read/write
vals.clear()
with lk.ReadTransaction(lock):
assert not vals['wrote']
with lk.WriteTransaction(lock, release=write):
assert not vals['wrote']
assert vals['wrote']
# write/read/write
vals.clear()
with lk.WriteTransaction(lock, release=write):
assert not vals['wrote']
with lk.ReadTransaction(lock):
assert not vals['wrote']
with lk.WriteTransaction(lock, release=write):
assert not vals['wrote']
assert not vals['wrote']
assert not vals['wrote']
assert vals['wrote']
# read/write/read/write
vals.clear()
with lk.ReadTransaction(lock):
with lk.WriteTransaction(lock, release=write):
assert not vals['wrote']
with lk.ReadTransaction(lock):
assert not vals['wrote']
with lk.WriteTransaction(lock, release=write):
assert not vals['wrote']
assert not vals['wrote']
assert not vals['wrote']
assert vals['wrote']
def p1(barrier, q1, q2):
# exchange pids
p1_pid = os.getpid()
q1.put(p1_pid)
p2_pid = q2.get()
# set up lock
lock = lk.Lock(lock_path, debug=True)
with lk.WriteTransaction(lock):
# p1 takes write lock and writes pid/host to file
barrier.wait() # ------------------------------------ 1
assert lock.pid == p1_pid
assert lock.host == host
# wait for p2 to verify contents of file
barrier.wait() # ---------------------------------------- 2
# wait for p2 to take a write lock
barrier.wait() # ---------------------------------------- 3
# verify pid/host info again
with lk.ReadTransaction(lock):
assert lock.old_pid == p1_pid
assert lock.old_host == host
assert lock.pid == p2_pid
assert lock.host == host
barrier.wait() # ---------------------------------------- 4
def p2(barrier, q1, q2):
# exchange pids
p2_pid = os.getpid()
p1_pid = q1.get()
q2.put(p2_pid)
# set up lock
lock = lk.Lock(lock_path, debug=True)
# p1 takes write lock and writes pid/host to file
barrier.wait() # ---------------------------------------- 1
# verify that p1 wrote information to lock file
with lk.ReadTransaction(lock):
assert lock.pid == p1_pid
assert lock.host == host
barrier.wait() # ---------------------------------------- 2
# take a write lock on the file and verify pid/host info
with lk.WriteTransaction(lock):
assert lock.old_pid == p1_pid
assert lock.old_host == host
assert lock.pid == p2_pid
assert lock.host == host
barrier.wait() # ------------------------------------ 3
# wait for p1 to verify pid/host info
barrier.wait() # ---------------------------------------- 4
def test_lock_in_current_directory(tmpdir):
"""Make sure locks work even when their parent directory does not exist."""
with tmpdir.as_cwd():
# test we can create a lock in the current directory
lock = lk.Lock('lockfile')
for i in range(10):
with lk.ReadTransaction(lock):
pass
with lk.WriteTransaction(lock):
pass
# and that we can do the same thing after it's already there
lock = lk.Lock('lockfile')
for i in range(10):
with lk.ReadTransaction(lock):
pass
with lk.WriteTransaction(lock):
pass
def test_read_lock_read_only_dir_writable_lockfile(lock_dir, lock_path):
"""read-only directory, writable lockfile."""
touch(lock_path)
with read_only(lock_dir):
lock = lk.Lock(lock_path)
with lk.ReadTransaction(lock):
pass
with lk.WriteTransaction(lock):
pass
def test_read_lock_no_lockfile(lock_dir, lock_path):
"""read-only directory, no lockfile (so can't create)."""
with read_only(lock_dir):
lock = lk.Lock(lock_path)
with pytest.raises(lk.CantCreateLockError):
with lk.ReadTransaction(lock):
pass
with pytest.raises(lk.CantCreateLockError):
with lk.WriteTransaction(lock):
pass
def test_read_lock_on_read_only_lockfile(lock_dir, lock_path):
"""read-only directory, read-only lockfile."""
touch(lock_path)
with read_only(lock_path, lock_dir):
lock = lk.Lock(lock_path)
with lk.ReadTransaction(lock):
pass
with pytest.raises(lk.LockROFileError):
with lk.WriteTransaction(lock):
pass
def test_nested_reads(lock_path):
"""Ensure that write transactions won't re-read data."""
def read():
vals['read'] += 1
vals = collections.defaultdict(lambda: 0)
lock = AssertLock(lock_path, vals)
# read/read
vals.clear()
assert vals['read'] == 0
with lk.ReadTransaction(lock, acquire=read):
assert vals['read'] == 1
with lk.ReadTransaction(lock, acquire=read):
assert vals['read'] == 1
# write/write
vals.clear()
assert vals['read'] == 0
with lk.WriteTransaction(lock, acquire=read):
assert vals['read'] == 1
with lk.WriteTransaction(lock, acquire=read):
assert vals['read'] == 1
# read/write
vals.clear()
assert vals['read'] == 0
with lk.ReadTransaction(lock, acquire=read):
assert vals['read'] == 1
with lk.WriteTransaction(lock, acquire=read):
assert vals['read'] == 1
# write/read/write
vals.clear()
assert vals['read'] == 0
with lk.WriteTransaction(lock, acquire=read):
assert vals['read'] == 1
with lk.ReadTransaction(lock, acquire=read):
assert vals['read'] == 1
with lk.WriteTransaction(lock, acquire=read):
assert vals['read'] == 1
# read/write/read/write
vals.clear()
assert vals['read'] == 0
with lk.ReadTransaction(lock, acquire=read):
assert vals['read'] == 1
with lk.WriteTransaction(lock, acquire=read):
assert vals['read'] == 1
with lk.ReadTransaction(lock, acquire=read):
assert vals['read'] == 1
with lk.WriteTransaction(lock, acquire=read):
assert vals['read'] == 1
def test_transaction(lock_path):
def enter_fn():
vals['entered'] = True
def exit_fn(t, v, tb):
vals['exited'] = True
vals['exception'] = (t or v or tb)
lock = lk.Lock(lock_path)
vals = {'entered': False, 'exited': False, 'exception': False}
with lk.ReadTransaction(lock, enter_fn, exit_fn):
pass
assert vals['entered']
assert vals['exited']
assert not vals['exception']
vals = {'entered': False, 'exited': False, 'exception': False}
with lk.WriteTransaction(lock, enter_fn, exit_fn):
pass
assert vals['entered']
assert vals['exited']
assert not vals['exception']
def do_read_with_exception(exit_fn):
with lk.ReadTransaction(lock, TestContextManager, exit_fn):
raise Exception()
def do_read_with_exception():
with lk.ReadTransaction(lock, enter_fn, exit_fn):
raise Exception()
