# Based on code from <http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/66012>
# Eventually (read: probably never) I'll rewrite this myself, so that it's not cookie-cutter code.



import sys, os, time

from signal import SIGTERM


def startstop(action,
              stdout='/dev/null',
              stderr=None,
              stdin='/dev/null',
              pidfile='pid.txt',
              startmsg = 'Started with pid %s' ):
    try:
        pf  = file(pidfile,'r')
        pid = int(pf.read().strip())
        pf.close()
    except IOError:
        pid = None
    if 'stop' == action or 'restart' == action:
        if not pid:
            mess = "Could not stop, pid file '%s' missing.\n"
            sys.stderr.write(mess % pidfile)
            if 'stop' == action:
                sys.exit(1)
            action = 'start'
            pid = None
        else:
           try:
              while 1:
                  os.kill(pid,SIGTERM)
                  time.sleep(1)
           except OSError, err:
              err = str(err)
              if err.find("No such process") > 0:
                  os.remove(pidfile)

                  sys.stderr.write("Killed process %s.\n" % pid)
                  if 'stop' == action:
                      sys.exit(0)
                  action = 'start'
                  pid = None
              else:
                  print str(err)
                  sys.exit(1)
    if 'start' == action:
        if pid:
            mess = "Start aborded since pid file '%s' exists.\n"
            sys.stderr.write(mess % pidfile)
            sys.exit(1)
        deamonize(stdout,stderr,stdin,pidfile,startmsg)
        return

def deamonize(stdout='/dev/null',
              stderr=None,
              stdin='/dev/null',
              pidfile=None,
              startmsg = 'started with pid %s'):
    '''
        This forks the current process into a daemon.
        The stdin, stdout, and stderr arguments are file names that
        will be opened and be used to replace the standard file descriptors
        in sys.stdin, sys.stdout, and sys.stderr.
        These arguments are optional and default to /dev/null.
        Note that stderr is opened unbuffered, so
        if it shares a file with stdout then interleaved output
        may not appear in the order that you expect.
    '''
    # Do first fork.
    try: 
        pid = os.fork() 
        if pid > 0: sys.exit(0) # Exit first parent.
    except OSError, e: 
        sys.stderr.write("fork #1 failed: (%d) %s\n" % (e.errno, e.strerror))
        sys.exit(1)
        
    # Decouple from parent environment.
    #os.chdir("/") 
    os.umask(0) 
    os.setsid() 
    
    # Do second fork.
    try: 
        pid = os.fork() 
        if pid > 0: sys.exit(0) # Exit second parent.
    except OSError, e: 
        sys.stderr.write("fork #2 failed: (%d) %s\n" % (e.errno, e.strerror))
        sys.exit(1)
     
    # Open file descriptors and print start message
    if not stderr: stderr = stdout
    si = file(stdin, 'r')
    so = file(stdout, 'a+')
    se = file(stderr, 'a+', 0)
    pid = str(os.getpid())
    sys.stderr.write("%s\n" % startmsg % pid)
    sys.stderr.flush()
    if pidfile: file(pidfile,'w+').write("%s\n" % pid)
    
    # Redirect standard file descriptors.
    os.dup2(si.fileno(), sys.stdin.fileno())
    os.dup2(so.fileno(), sys.stdout.fileno())
    os.dup2(se.fileno(), sys.stderr.fileno())