def write_pidfile(rundir, process_type=PROCESS_TYPE,
                  name=None, file=None): #@ReservedAssignment
    """
    Write a pid file in the run directory, using the given process type
    and process name for the filename.

    @rtype:   str
    @returns: full path to the pid file that was written
    """
    from feat.common.run import get_pidpath
    # don't shadow builtin file
    pid_file = file
    if pid_file is None:
        _ensure_dir(rundir, "rundir")
        filename = get_pidpath(rundir, process_type, name)
        pid_file = open(filename, 'w')
    else:
        filename = pid_file.name
    pid_file.write("%d\n" % (os.getpid(), ))
    pid_file.close()
    os.chmod(filename, 0644)
    return filename
Write a pid file in the run directory, using the given process type
    and process name for the filename.

    @rtype:   str
    @returns: full path to the pid file that was written