U UV@stdZddlmZddlZddlZddlZddlmZmZm Z m Z m Z m Z GdddeZ dd Zd d Zd d ZdS)z8 Lockfile behaviour implemented via Unix PID files. )absolute_importN)LockBase AlreadyLocked LockFailed NotLocked NotMyLock LockTimeoutc@sLeZdZdZdddZddZdd Zd d Zdd d ZddZ ddZ dS) PIDLockFileaA Lockfile implemented as a Unix PID file. The lock file is a normal file named by the attribute `path`. A lock's PID file contains a single line of text, containing the process ID (PID) of the process that acquired the lock. >>> lock = PIDLockFile('somefile') >>> lock = PIDLockFile('somefile') FNcCst||d||j|_dS)NF)r__init__pathZ unique_name)selfr Zthreadedtimeoutr/pidlockfile.pyr $szPIDLockFile.__init__cCs t|jS)z- Get the PID from the lock file. )read_pid_from_pidfiler r rrrread_pid*szPIDLockFile.read_pidcCstj|jS)zv Test if the lock is currently held. The lock is held if the PID file for this lock exists. )osr existsrrrr is_locked/szPIDLockFile.is_lockedcCs|ot|kS)z Test if the lock is held by the current process. Returns ``True`` if the current process ID matches the number stored in the PID file. )rrgetpidrrrrr i_am_locking7szPIDLockFile.i_am_lockingc Cs|dk r |n|j}t}|dk r2|dkr2||7}zt|jWntk r}zt|jtjkrt|kr|dk r|dkrtd|jntd|jt |dk r|dpdnt d|jW5d}~XYq2XdSq2dS)z Acquire the lock. Creates the PID file for this lock, or raises an error if the lock could not be acquired. Nrz&Timeout waiting to acquire lock for %sz%s is already locked g?zfailed to create %s) rtimewrite_pid_to_pidfiler OSErrorerrnoZEEXISTr rsleepr)r rZend_timeexcrrracquire?s&   zPIDLockFile.acquirecCs:|std|j|s,td|jt|jdS)z Release the lock. Removes the PID file to release the lock, or raises an error if the current process does not hold the lock. z%s is not lockedz%s is locked, but not by meN)rrr rrremove_existing_pidfilerrrrrelease_s zPIDLockFile.releasecCst|jdS)z Break an existing lock. Removes the PID file if it already exists, otherwise does nothing. N)r!r rrrr break_locklszPIDLockFile.break_lock)FN)N) __name__ __module__ __qualname____doc__r rrrr r"r#rrrrr s   r cCsbd}zt|d}Wntk r&Yn8X|}z t|}Wntk rTYnX||S)z Read the PID recorded in the named PID file. Read and return the numeric PID recorded as text in the named PID file. If the PID file cannot be read, or if the content is not a valid PID, return ``None``. Nr)openIOErrorreadlinestripint ValueErrorclose) pidfile_pathpidpidfilelinerrrrvs  rcCsRtjtjBtjB}d}t|||}t|d}t}|d||dS)u Write the PID in the named PID file. Get the numeric process ID (“PID”) of the current process and write it to the named file as a line of text. iwz%s N) rO_CREATO_EXCLO_WRONLYr)fdopenrwriter/)r0Z open_flagsZ open_modeZ pidfile_fdr2r1rrrrs rc CsFzt|Wn2tk r@}z|jtjkr.nW5d}~XYnXdS)z Remove the named PID file if it exists. Removing a PID file that doesn't already exist puts us in the desired state, so we ignore the condition if the file does not exist. N)rremoverrZENOENT)r0rrrrr!s  r!)r'Z __future__rrrrrrrrrr r rrr!rrrr s  ]"