.. _fbf.memcached:

memcached
~~~~~~~~~

.. automodule:: fbf.memcached
        :show-inheritance:
        :members:
        :undoc-members:

CODE
----

    ::

        # fbf/memcached.py
        #
        #
        
        """ memcached support functions. """
        
.. _fbf.memcached_fbf_imports:

fbf imports
--------------

    ::

        
        from fbf.lib.datadir import getdatadir
        from fbf.lib.config import getmainconfig
        
.. _fbf.memcached_basic_imports:

basic imports
----------------

    ::

        
        import os
        import os.path
        import logging
        import time
        
        mc = None
        
        def isactive(path):
            stats = None
            if not mc: mcboot()
            if mc: stats = mc.get_stats()
            if stats: return stats
            return False
        
        def mcboot():
            if not getmainconfig().memcached: return
            logging.warn("memcached is enabled")
            try:
                import fbf.contrib.memcache as memcache
                rundir = getdatadir() + os.sep + 'run'
                sock = os.path.abspath(rundir + os.sep + "memcached.socket")
                global mc
                mc = memcache.Client(["unix:%s" % sock], debug=0)
                return isactive(sock)
            except ImportError as ex: logging.warn("using builtin cache - %s" % str(ex))
            except Exception as ex: logging.warn("error starting memcached client: %s" % str(ex))
        
        def getmc():
            if not getmainconfig().memcached: return
            logging.warn("memcached is enabled")
            global mc
            if mc: return mc
            else:
                startmcdaemon()
                if mcboot(): return mc
        
        def startmcdaemon():
            if not getmainconfig().memcached: return
            logging.warn("starting memcached daemon")
            try:
                from fbf.utils.popen import gozerpopen
                rundir = getdatadir() + os.sep + 'run'
                sock = os.path.abspath(rundir + os.sep + "memcached.socket")
                logging.warn("using unix socket %s" % sock)
                pidfile = sock[:-7] + ".pid"
                if os.path.exists(sock) and isactive(sock): logging.warn("memcached daemon is already running") ; return
                args = [[]]*4
                args[0] = "memcached"
                args[1] = "-s%s" % sock
                args[2] = "-P%s" % pidfile
                args[3] = "-d"
                logging.debug("running %s" % " ".join(args))
                proces = gozerpopen(args)
            except Exception as ex:
                if "No such file" in str(ex): logging.warn("no memcached installed") 
                else: logging.error('error running popen: %s' % str(ex))
                return
            data = proces.fromchild.readlines()
            returncode = proces.close()
            if returncode == 0: logging.warn("memcached started")
            else: logging.warn("can't start memcached (%s)" % returncode)
        
        def killmcdaemon():
            if not getmainconfig().memcached: return
            logging.warn("killing memcached daemon")
            rundir = getdatadir() + os.sep + 'run'
            sock = os.path.abspath(rundir + os.sep + "memcached.socket")
            pidfile = sock[:-7] + ".pid"
            try: pid = int(open(pidfile, "r").read().strip())
            except Exception as ex : logging.warn("can't determine pid of memcached from %s - %s" % (pidfile,str(ex))) ; return False
            logging.warn("pid is %s" % pid)
            data = isactive(sock)
            if not data: logging.warn("memcached is not runniing") ; return False
            try: curr_connections = int(data[0][1]["curr_connections"])
            except Exception as ex: logging.warn("can't determine current connections of memcached .. not killing - %s" % str(ex)) ; return False
            if curr_connections and curr_connections != 1: logging.warn("current connections of memcached is %s .. not killing" % curr_connections) ; return False
            try: os.kill(pid, 15) ; logging.warn("killed memcached with pid %s" % pid)
            except Exception as ex: logging.warn("failed to kill memcached (%s) - %s" % (pid, str(ex)))
            try: os.remove(pidfile)
            except: pass