# lockfile --help Usage: lockfile -v | -nnn | -r nnn | -l nnn | -s nnn | -! | -ml | -mu | file ... # rpm -qf `which lockfile` procmail-3.22-25.1.el6.x86_64As can be seen above, /usr/bin/lockfile is part of procmail, which comes with its own dependencies (usually sendmail or postfix etc.). I did not like having to install those MTA type dependencies to setup procmail for locking purposes. This is the reason why I wrote lockfile.py.
#!/usr/bin/python # Author Evuraan Gmail dot com import optparse,sys,os,time def usage(): print """ Usage : lockfile.py
Usage : lockfile.py -l Example : lockfile.py -l 1300 /tmp/my.lockfile.txt Example : lockfile.py /tmp/my.lockfile.txt """ def remove_lockfile(lock_file): os.remove(lock_file) def set_lockfile(lock_file): write_file = open(lock_file,"w",) write_file.write(str(time.time())) write_file.close() if os.path.isfile(lock_file): # file exists, good enough for us. return 0 else: return 1 #if the lockfile exists, check for locktimeout def checklock(lock_file): if os.path.isfile(lock_file): # lock file exists. check how old etc. mtime = float(os.path.getmtime(lock_file)) delta = time.time() - mtime if float(delta) >= float(locktimeout): # file is stale, over write it if set_lockfile(lock_file) != 0: sys.exit(1) else: #file is not stale. new. spanking new. sys.exit(1) else: # no lock file. if set_lockfile(lock_file) != 0: sys.exit(1) if __name__ == "__main__": parser = optparse.OptionParser() parser.add_option('-l', '--locktimeout', dest="locktimeout", type="int", default="3489999999", help="""If you specify a locktimeout then a lockfile will be removed by force after locktimeout seconds have passed since the lockfile was last modified/created (most likely by some other program that unexpectedly died a long time ago, and hence could not clean up any leftover lockfiles).""" ) options,remainder = parser.parse_args() #print "locktimeout :", options.locktimeout #print "remainder :", remainder global locktimeout locktimeout = options.locktimeout try: if len(remainder) == 0: print "Invalid usage" usage() sys.exit(2) else: global lock_file lock_file = remainder except: sys.exit(2) #print "Ahem", lock_file checklock(lock_file)
$ wget https://evuraan.info/evuraan/stuff/lockfile.py.txt --no-check-certificate -O lock.py
$ ./lockfile.py Invalid usage Usage : lockfile.py
Usage : lockfile.py -l Example : lockfile.py -l 1300 /tmp/my.lockfile.txt Example : lockfile.py /tmp/my.lockfile.txt $ ./lockfile.py --help Usage: lockfile.py [options] Options: -h, --help show this help message and exit -l LOCKTIMEOUT, --locktimeout=LOCKTIMEOUT If you specify a locktimeout then a lockfile will be removed by force after locktimeout seconds have passed since the lockfile was last modified/created (most likely by some other program that unexpectedly died a long time ago, and hence could not clean up any leftover lockfiles). $ ./lockfile.py /tmp/mylockfile ; echo $? 0 $ ./lockfile.py /tmp/mylockfile ; echo $? 1
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