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Solaar
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documentation and logging for

This commit is contained in:
Daniel Pavel 2013-06-07 14:24:05 +02:00
parent 996597dcb1
commit a1ecebf5bf
1 changed files with 17 additions and 8 deletions
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25
lib/solaar/appinstance.py
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@ -12,18 +12,26 @@ import fcntl as _fcntl
import os.path as _path
import os as _os
from solaar import NAME
_program = NAME.lower()
del NAME
from logging import getLogger, DEBUG as _DEBUG
_log = getLogger('solaar.appinstance')
_log = getLogger(__name__)
del getLogger
def check():
"""Select a file lock location and try to acquire it.
Suitable locations are $XDG_RUNTIME_DIR, /run/lock, /var/lock, and $TMPDIR.
The first one found and writable is used.
"""
# ensure no more than a single instance runs at a time
lock_fd = None
for p in _os.environ.get('XDG_RUNTIME_DIR'), '/run/lock', '/var/lock', _os.environ.get('TMPDIR', '/tmp'):
# pick the first temporary writable folder
if p and _path.isdir(p) and _os.access(p, _os.W_OK):
lock_path = _path.join(p, 'solaar.single-instance.%d' % _os.getuid())
lock_path = _path.join(p, _program + '.single-instance.' + str(_os.getuid()))
try:
lock_fd = open(lock_path, 'wb')
if _log.isEnabledFor(_DEBUG):
@ -36,23 +44,24 @@ def check():
try:
_fcntl.flock(lock_fd, _fcntl.LOCK_EX | _fcntl.LOCK_NB)
if _log.isEnabledFor(_DEBUG):
_log.debug("acquired single-instance lock (%s)", lock_fd)
_log.debug("acquired single-instance lock %s", lock_fd)
return lock_fd
except IOError as e:
if e.errno == 11:
_log.warn("lock file is busy, solaar already running: %s", e)
_log.warn("lock file is busy, %s already running: %s", _program, e)
import sys
sys.exit("solaar: error: Solaar is already running.")
sys.exit(_program + ": error: already running")
else:
raise
else:
import sys
print ("solaar: warning: failed to create single instance lock file, ignoring.", file=sys.stderr)
print (_program + ": warning: no suitable location for the lockfile found; ignoring", file=sys.stderr)
def close(lock_fd):
if _log.isEnabledFor(_DEBUG):
_log.debug("releasing single-instance lock (%s)", lock_fd)
"""Release a file lock."""
if lock_fd:
_fcntl.flock(lock_fd, _fcntl.LOCK_UN)
lock_fd.close()
if _log.isEnabledFor(_DEBUG):
_log.debug("released single-instance lock %s", lock_fd)