def lock_path(directory, timeout=10):
"""
Context manager that acquires a lock on a directory. This will block until
the lock can be acquired, or the timeout time has expired (whichever occurs
first).
For locking exclusively, file or directory has to be opened in Write mode.
Python doesn't allow directories to be opened in Write Mode. So we
workaround by locking a hidden file in the directory.
:param directory: directory to be locked
:param timeout: timeout (in seconds)
"""
mkdirs(directory)
lockpath = '%s/.lock' % directory
fd = os.open(lockpath, os.O_WRONLY | os.O_CREAT)
try:
with LockTimeout(timeout, lockpath):
while True:
try:
fcntl.flock(fd, fcntl.LOCK_EX | fcntl.LOCK_NB)
break
except IOError, err:
if err.errno != errno.EAGAIN:
raise
sleep(0.01)
yield True
def lock_file(filename, timeout=10, append=False, unlink=True):
"""
Context manager that acquires a lock on a file. This will block until
the lock can be acquired, or the timeout time has expired (whichever occurs
first).
:param filename: file to be locked
:param timeout: timeout (in seconds)
:param append: True if file should be opened in append mode
:param unlink: True if the file should be unlinked at the end
"""
flags = os.O_CREAT | os.O_RDWR
if append:
flags |= os.O_APPEND
mode = 'a+'
else:
mode = 'r+'
fd = os.open(filename, flags)
file_obj = os.fdopen(fd, mode)
try:
with LockTimeout(timeout, filename):
while True:
try:
fcntl.flock(fd, fcntl.LOCK_EX | fcntl.LOCK_NB)
break
except IOError, err:
if err.errno != errno.EAGAIN:
raise
sleep(0.01)
yield file_obj
def _timeout(self, call):
with LockTimeout(self.timeout, self.db_file):
while True:
try:
return call()
except sqlite3.OperationalError as e:
if 'locked' not in str(e):
raise
sleep(0.05)
def _db_timeout(timeout, db_file, call):
with LockTimeout(timeout, db_file):
retry_wait = 0.001
while True:
try:
return call()
except sqlite3.OperationalError as e:
if 'locked' not in str(e):
raise
sleep(retry_wait)
retry_wait = min(retry_wait * 2, 0.05)
def lock_path(directory, timeout=10):
"""
Context manager that acquires a lock on a directory. This will block until
the lock can be acquired, or the timeout time has expired (whichever occurs
first).
:param directory: directory to be locked
:param timeout: timeout (in seconds)
"""
mkdirs(directory)
fd = os.open(directory, os.O_RDONLY)
try:
with LockTimeout(timeout, directory):
while True:
try:
fcntl.flock(fd, fcntl.LOCK_EX | fcntl.LOCK_NB)
break
except IOError, err:
if err.errno != errno.EAGAIN:
raise
sleep(0.01)
yield True
