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OpenStack Study: control.py**** CubicPower OpenStack Study **** def gated_by(predicate): def wrap(f): def wrapped_f(*args): if predicate: return f(*args) else: return None return wrapped_f return wrap
**** CubicPower OpenStack Study **** def pid_files(server, pid_file): pid_files = [] if pid_file: if os.path.exists(os.path.abspath(pid_file)): pid_files = [os.path.abspath(pid_file)] else: if os.path.exists('/var/run/glance/%s.pid' % server): pid_files = ['/var/run/glance/%s.pid' % server] for pid_file in pid_files: pid = int(open(pid_file).read().strip()) yield pid_file, pid
**** CubicPower OpenStack Study **** def do_start(verb, pid_file, server, args): if verb != 'Respawn' and pid_file == CONF.pid_file: for pid_file, pid in pid_files(server, pid_file): if os.path.exists('/proc/%s' % pid): print(_("%(serv)s appears to already be running: %(pid)s") % {'serv': server, 'pid': pid_file}) return else: print(_("Removing stale pid file %s") % pid_file) os.unlink(pid_file) try: resource.setrlimit(resource.RLIMIT_NOFILE, (MAX_DESCRIPTORS, MAX_DESCRIPTORS)) resource.setrlimit(resource.RLIMIT_DATA, (MAX_MEMORY, MAX_MEMORY)) except ValueError: print(_('Unable to increase file descriptor limit. ' 'Running as non-root?')) os.environ['PYTHON_EGG_CACHE'] = '/tmp' def write_pid_file(pid_file, pid): fp = open(pid_file, 'w') fp.write('%d\n' % pid) fp.close() def redirect_to_null(fds): with open(os.devnull, 'r+b') as nullfile: for desc in fds: # close fds try: os.dup2(nullfile.fileno(), desc) except OSError: pass def redirect_to_syslog(fds, server): log_cmd = 'logger -t "%s[%d]"' % (server, os.getpid()) process = subprocess.Popen(log_cmd, shell=True, stdin=subprocess.PIPE) for desc in fds: # pipe to logger command try: os.dup2(process.stdin.fileno(), desc) except OSError: pass def redirect_stdio(server, capture_output): input = [sys.stdin.fileno()] output = [sys.stdout.fileno(), sys.stderr.fileno()] redirect_to_null(input) if capture_output: redirect_to_syslog(output, server) else: redirect_to_null(output) @gated_by(CONF.capture_output) def close_stdio_on_exec(): fds = [sys.stdin.fileno(), sys.stdout.fileno(), sys.stderr.fileno()] for desc in fds: # set close on exec flag fcntl.fcntl(desc, fcntl.F_SETFD, fcntl.FD_CLOEXEC) def launch(pid_file, conf_file=None, capture_output=False, await_time=0): args = [server] msg = (_('%(verb)sing %(serv)s') % {'verb': verb, 'serv': server}) if conf_file: args += ['--config-file', conf_file] msg += 'with %s' % conf_file print(msg) close_stdio_on_exec() pid = os.fork() if pid == 0: os.setsid() redirect_stdio(server, capture_output) try: os.execlp('%s' % server, *args) except OSError as e: msg = (_('unable to launch %(serv)s. Got error: %(e)s') % {'serv': server, 'e': e}) sys.exit(msg) sys.exit(0) else: write_pid_file(pid_file, pid) await_child(pid, await_time) return pid @gated_by(CONF.await_child) def await_child(pid, await_time): bail_time = time.time() + await_time while time.time() < bail_time: reported_pid, status = os.waitpid(pid, os.WNOHANG) if reported_pid == pid: global exitcode exitcode = os.WEXITSTATUS(status) break time.sleep(0.05) conf_file = None if args and os.path.exists(args[0]): conf_file = os.path.abspath(os.path.expanduser(args[0])) return launch(pid_file, conf_file, CONF.capture_output, CONF.await_child)
**** CubicPower OpenStack Study **** def do_check_status(pid_file, server): if os.path.exists(pid_file): pid = open(pid_file).read().strip() print(_("%(serv)s (pid %(pid)s) is running...") % {'serv': server, 'pid': pid}) else: print(_("%s is stopped") % server)
**** CubicPower OpenStack Study **** def get_pid_file(server, pid_file): pid_file = (os.path.abspath(pid_file) if pid_file else '/var/run/glance/%s.pid' % server) dir, file = os.path.split(pid_file) if not os.path.exists(dir): try: os.makedirs(dir) except OSError: pass if not os.access(dir, os.W_OK): fallback = os.path.join(tempfile.mkdtemp(), '%s.pid' % server) msg = (_('Unable to create pid file %(pid)s. Running as non-root?\n' 'Falling back to a temp file, you can stop %(service)s ' 'service using:\n' ' %(file)s %(server)s stop --pid-file %(fb)s') % {'pid': pid_file, 'service': server, 'file': __file__, 'server': server, 'fb': fallback}) print(msg) pid_file = fallback return pid_file
**** CubicPower OpenStack Study **** def do_stop(server, args, graceful=False): if graceful and server in GRACEFUL_SHUTDOWN_SERVERS: sig = signal.SIGHUP else: sig = signal.SIGTERM did_anything = False pfiles = pid_files(server, CONF.pid_file) for pid_file, pid in pfiles: did_anything = True try: os.unlink(pid_file) except OSError: pass try: print(_('Stopping %(serv)s (pid %(pid)s) with signal(%(sig)s)') % {'serv': server, 'pid': pid, 'sig': sig}) os.kill(pid, sig) except OSError: print(_("Process %d not running") % pid) for pid_file, pid in pfiles: for _junk in xrange(150): # 15 seconds if not os.path.exists('/proc/%s' % pid): break time.sleep(0.1) else: print(_('Waited 15 seconds for pid %(pid)s (%(file)s) to die;' ' giving up') % {'pid': pid, 'file': pid_file}) if not did_anything: print(_('%s is already stopped') % server)
**** CubicPower OpenStack Study **** def add_command_parsers(subparsers): cmd_parser = argparse.ArgumentParser(add_help=False) cmd_subparsers = cmd_parser.add_subparsers(dest='command') for cmd in ALL_COMMANDS: parser = cmd_subparsers.add_parser(cmd) parser.add_argument('args', nargs=argparse.REMAINDER) for server in ALL_SERVERS: full_name = 'glance-' + server parser = subparsers.add_parser(server, parents=[cmd_parser]) parser.set_defaults(servers=[full_name]) parser = subparsers.add_parser(full_name, parents=[cmd_parser]) parser.set_defaults(servers=[full_name]) parser = subparsers.add_parser('all', parents=[cmd_parser]) parser.set_defaults(servers=['glance-' + s for s in ALL_SERVERS])
**** CubicPower OpenStack Study **** def main(): global exitcode opts = [ cfg.SubCommandOpt('server', title='Server types', help='Available server types', handler=add_command_parsers), cfg.StrOpt('pid-file', metavar='PATH', help='File to use as pid file. Default: ' '/var/run/glance/$server.pid.'), cfg.IntOpt('await-child', metavar='DELAY', default=0, help='Period to wait for service death ' 'in order to report exit code ' '(default is to not wait at all).'), cfg.BoolOpt('capture-output', default=False, help='Capture stdout/err in syslog ' 'instead of discarding it.'), cfg.BoolOpt('respawn', default=False, help='Restart service on unexpected death.'), ] CONF.register_cli_opts(opts) config.parse_args(usage=USAGE) @gated_by(CONF.await_child) @gated_by(CONF.respawn) def mutually_exclusive(): sys.stderr.write('--await-child and --respawn are mutually exclusive') sys.exit(1) mutually_exclusive() @gated_by(CONF.respawn) def anticipate_respawn(children): while children: pid, status = os.wait() if pid in children: (pid_file, server, args) = children.pop(pid) running = os.path.exists(pid_file) one_second_ago = time.time() - 1 bouncing = (running and os.path.getmtime(pid_file) >= one_second_ago) if running and not bouncing: args = (pid_file, server, args) new_pid = do_start('Respawn', *args) children[new_pid] = args else: rsn = 'bouncing' if bouncing else 'deliberately stopped' print(_('Supressed respawn as %(serv)s was %(rsn)s.') % {'serv': server, 'rsn': rsn}) if CONF.server.command == 'start': children = {} for server in CONF.server.servers: pid_file = get_pid_file(server, CONF.pid_file) args = (pid_file, server, CONF.server.args) pid = do_start('Start', *args) children[pid] = args anticipate_respawn(children) if CONF.server.command == 'status': for server in CONF.server.servers: pid_file = get_pid_file(server, CONF.pid_file) do_check_status(pid_file, server) if CONF.server.command == 'stop': for server in CONF.server.servers: do_stop(server, CONF.server.args) if CONF.server.command == 'shutdown': for server in CONF.server.servers: do_stop(server, CONF.server.args, graceful=True) if CONF.server.command == 'restart': for server in CONF.server.servers: do_stop(server, CONF.server.args) for server in CONF.server.servers: pid_file = get_pid_file(server, CONF.pid_file) do_start('Restart', pid_file, server, CONF.server.args) if (CONF.server.command == 'reload' or CONF.server.command == 'force-reload'): for server in CONF.server.servers: do_stop(server, CONF.server.args, graceful=True) pid_file = get_pid_file(server, CONF.pid_file) do_start('Restart', pid_file, server, CONF.server.args) sys.exit(exitcode)
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