mopidy.commands — Mopidy 3.0.2 documentation

# Source code for mopidy.commands

    import argparse
    import collections
    import contextlib
    import logging
    import os
    import pathlib
    import signal
    import sys

    import pykka
    from pykka.messages import ProxyCall

    from mopidy import config as config_lib
    from mopidy import exceptions
    from mopidy.audio import Audio
    from mopidy.core import Core
    from mopidy.internal import deps, process, timer, versioning
    from mopidy.internal.gi import GLib

    logger = logging.getLogger(__name__)

    _default_config = [
        (pathlib.Path(base) / "mopidy" / "mopidy.conf").resolve()
        for base in GLib.get_system_config_dirs() + [GLib.get_user_config_dir()]
    ]
    DEFAULT_CONFIG = ":".join(map(str, _default_config))

    def config_files_type(value):
        return value.split(":")

    def config_override_type(value):
        try:
            section, remainder = value.split("/", 1)
            key, value = remainder.split("=", 1)
            return (section.strip(), key.strip(), value.strip())
        except ValueError:
            raise argparse.ArgumentTypeError(
                f"{value} must have the format section/key=value"
            )

    class _ParserError(Exception):
        def __init__(self, message):
            self.message = message

    class _HelpError(Exception):
        pass

    class _ArgumentParser(argparse.ArgumentParser):
        def error(self, message):
            raise _ParserError(message)

    class _HelpAction(argparse.Action):
        def __init__(self, option_strings, dest=None, help=None):
            super().__init__(
                option_strings=option_strings,
                dest=dest or argparse.SUPPRESS,
                default=argparse.SUPPRESS,
                nargs=0,
                help=help,
            )

        def __call__(self, parser, namespace, values, option_string=None):
            raise _HelpError()

    class Command:

        """Command parser and runner for building trees of commands.

        This class provides a wraper around :class:`argparse.ArgumentParser`
        for handling this type of command line application in a better way than
        argprases own sub-parser handling.
        """

        help = None
        #: Help text to display in help output.

        def __init__(self):
            self._children = collections.OrderedDict()
            self._arguments = []
            self._overrides = {}

        def _build(self):
            actions = []
            parser = _ArgumentParser(add_help=False)
            parser.register("action", "help", _HelpAction)

            for args, kwargs in self._arguments:
                actions.append(parser.add_argument(*args, **kwargs))

            parser.add_argument(
                "_args", nargs=argparse.REMAINDER, help=argparse.SUPPRESS
            )
            return parser, actions

        def add_child(self, name, command):
            """Add a child parser to consider using.

            :param name: name to use for the sub-command that is being added.
            :type name: string
            """
            self._children[name] = command

        def add_argument(self, *args, **kwargs):
            """Add an argument to the parser.

            This method takes all the same arguments as the
            :class:`argparse.ArgumentParser` version of this method.
            """
            self._arguments.append((args, kwargs))

        def set(self, **kwargs):
            """Override a value in the finaly result of parsing."""
            self._overrides.update(kwargs)

        def exit(self, status_code=0, message=None, usage=None):
            """Optionally print a message and exit."""
            print("\n\n".join(m for m in (usage, message) if m))
            sys.exit(status_code)

        def format_usage(self, prog=None):
            """Format usage for current parser."""
            actions = self._build()[1]
            prog = prog or os.path.basename(sys.argv[0])
            return self._usage(actions, prog) + "\n"

        def _usage(self, actions, prog):
            formatter = argparse.HelpFormatter(prog)
            formatter.add_usage(None, actions, [])
            return formatter.format_help().strip()

        def format_help(self, prog=None):
            """Format help for current parser and children."""
            actions = self._build()[1]
            prog = prog or os.path.basename(sys.argv[0])

            formatter = argparse.HelpFormatter(prog)
            formatter.add_usage(None, actions, [])

            if self.help:
                formatter.add_text(self.help)

            if actions:
                formatter.add_text("OPTIONS:")
                formatter.start_section(None)
                formatter.add_arguments(actions)
                formatter.end_section()

            subhelp = []
            for name, child in self._children.items():
                child._subhelp(name, subhelp)

            if subhelp:
                formatter.add_text("COMMANDS:")
                subhelp.insert(0, "")

            return formatter.format_help() + "\n".join(subhelp)

        def _subhelp(self, name, result):
            actions = self._build()[1]

            if self.help or actions:
                formatter = argparse.HelpFormatter(name)
                formatter.add_usage(None, actions, [], "")
                formatter.start_section(None)
                formatter.add_text(self.help)
                formatter.start_section(None)
                formatter.add_arguments(actions)
                formatter.end_section()
                formatter.end_section()
                result.append(formatter.format_help())

            for childname, child in self._children.items():
                child._subhelp(" ".join((name, childname)), result)

        def parse(self, args, prog=None):
            """Parse command line arguments.

            Will recursively parse commands until a final parser is found or an
            error occurs. In the case of errors we will print a message and exit.
            Otherwise, any overrides are applied and the current parser stored
            in the command attribute of the return value.

            :param args: list of arguments to parse
            :type args: list of strings
            :param prog: name to use for program
            :type prog: string
            :rtype: :class:`argparse.Namespace`
            """
            prog = prog or os.path.basename(sys.argv[0])
            try:
                return self._parse(
                    args, argparse.Namespace(), self._overrides.copy(), prog
                )
            except _HelpError:
                self.exit(0, self.format_help(prog))

        def _parse(self, args, namespace, overrides, prog):
            overrides.update(self._overrides)
            parser, actions = self._build()

            try:
                result = parser.parse_args(args, namespace)
            except _ParserError as exc:
                self.exit(1, str(exc), self._usage(actions, prog))

            if not result._args:
                for attr, value in overrides.items():
                    setattr(result, attr, value)
                delattr(result, "_args")
                result.command = self
                return result

            child = result._args.pop(0)
            if child not in self._children:
                usage = self._usage(actions, prog)
                self.exit(1, f"unrecognized command: {child}", usage)

            return self._children[child]._parse(
                result._args, result, overrides, " ".join([prog, child])
            )

        def run(self, *args, **kwargs):
            """Run the command.

            Must be implemented by sub-classes that are not simply an intermediate
            in the command namespace.
            """
            raise NotImplementedError

    @contextlib.contextmanager
    def _actor_error_handling(name):
        try:
            yield
        except exceptions.BackendError as exc:
            logger.error("Backend (%s) initialization error: %s", name, exc)
        except exceptions.FrontendError as exc:
            logger.error("Frontend (%s) initialization error: %s", name, exc)
        except exceptions.MixerError as exc:
            logger.error("Mixer (%s) initialization error: %s", name, exc)
        except Exception:
            logger.exception("Got un-handled exception from %s", name)

    # TODO: move out of this utility class
    class RootCommand(Command):
        def __init__(self):
            super().__init__()
            self.set(base_verbosity_level=0)
            self.add_argument(
                "-h", "--help", action="help", help="Show this message and exit"
            )
            self.add_argument(
                "--version",
                action="version",
                version=f"Mopidy {versioning.get_version()}",
            )
            self.add_argument(
                "-q",
                "--quiet",
                action="store_const",
                const=-1,
                dest="verbosity_level",
                help="less output (warning level)",
            )
            self.add_argument(
                "-v",
                "--verbose",
                action="count",
                dest="verbosity_level",
                default=0,
                help="more output (repeat up to 4 times for even more)",
            )
            self.add_argument(
                "--config",
                action="store",
                dest="config_files",
                type=config_files_type,
                default=DEFAULT_CONFIG,
                metavar="FILES",
                help="config files to use, colon seperated, later files override",
            )
            self.add_argument(
                "-o",
                "--option",
                action="append",
                dest="config_overrides",
                type=config_override_type,
                metavar="OPTIONS",
                help="`section/key=value` values to override config options",
            )

        def run(self, args, config):
            def on_sigterm(loop):
                logger.info("GLib mainloop got SIGTERM. Exiting...")
                loop.quit()

            loop = GLib.MainLoop()
            GLib.unix_signal_add(
                GLib.PRIORITY_DEFAULT, signal.SIGTERM, on_sigterm, loop
            )

            mixer_class = self.get_mixer_class(config, args.registry["mixer"])
            backend_classes = args.registry["backend"]
            frontend_classes = args.registry["frontend"]
            core = None

            exit_status_code = 0
            try:
                mixer = None
                if mixer_class is not None:
                    mixer = self.start_mixer(config, mixer_class)
                if mixer:
                    self.configure_mixer(config, mixer)
                audio = self.start_audio(config, mixer)
                backends = self.start_backends(config, backend_classes, audio)
                core = self.start_core(config, mixer, backends, audio)
                self.start_frontends(config, frontend_classes, core)
                logger.info("Starting GLib mainloop")
                loop.run()
            except (
                exceptions.BackendError,
                exceptions.FrontendError,
                exceptions.MixerError,
            ):
                logger.info("Initialization error. Exiting...")
                exit_status_code = 1
            except KeyboardInterrupt:
                logger.info("Interrupted. Exiting...")
            except Exception:
                logger.exception("Uncaught exception")
            finally:
                loop.quit()
                self.stop_frontends(frontend_classes)
                self.stop_core(core)
                self.stop_backends(backend_classes)
                self.stop_audio()
                if mixer_class is not None:
                    self.stop_mixer(mixer_class)
                process.stop_remaining_actors()
            return exit_status_code

        def get_mixer_class(self, config, mixer_classes):
            logger.debug(
                "Available Mopidy mixers: %s",
                ", ".join(m.__name__ for m in mixer_classes) or "none",
            )

            if config["audio"]["mixer"] == "none":
                logger.debug("Mixer disabled")
                return None

            selected_mixers = [
                m for m in mixer_classes if m.name == config["audio"]["mixer"]
            ]
            if len(selected_mixers) != 1:
                logger.error(
                    'Did not find unique mixer "%s". Alternatives are: %s',
                    config["audio"]["mixer"],
                    ", ".join([m.name for m in mixer_classes]) + ", none" or "none",
                )
                process.exit_process()
            return selected_mixers[0]

        def start_mixer(self, config, mixer_class):
            logger.info("Starting Mopidy mixer: %s", mixer_class.__name__)
            with _actor_error_handling(mixer_class.__name__):
                mixer = mixer_class.start(config=config).proxy()
                try:
                    mixer.ping().get()
                    return mixer
                except pykka.ActorDeadError as exc:
                    logger.error("Actor died: %s", exc)
            return None

        def configure_mixer(self, config, mixer):
            volume = config["audio"]["mixer_volume"]
            if volume is not None:
                mixer.set_volume(volume)
                logger.info("Mixer volume set to %d", volume)
            else:
                logger.debug("Mixer volume left unchanged")

        def start_audio(self, config, mixer):
            logger.info("Starting Mopidy audio")
            return Audio.start(config=config, mixer=mixer).proxy()

        def start_backends(self, config, backend_classes, audio):
            logger.info(
                "Starting Mopidy backends: %s",
                ", ".join(b.__name__ for b in backend_classes) or "none",
            )

            backends = []
            for backend_class in backend_classes:
                with _actor_error_handling(backend_class.__name__):
                    with timer.time_logger(backend_class.__name__):
                        backend = backend_class.start(
                            config=config, audio=audio
                        ).proxy()
                        backends.append(backend)

            # Block until all on_starts have finished, letting them run in parallel
            for backend in backends[:]:
                try:
                    backend.ping().get()
                except pykka.ActorDeadError as exc:
                    backends.remove(backend)
                    logger.error("Actor died: %s", exc)

            return backends

        def start_core(self, config, mixer, backends, audio):
            logger.info("Starting Mopidy core")
            core = Core.start(
                config=config, mixer=mixer, backends=backends, audio=audio
            ).proxy()
            call = ProxyCall(attr_path=["_setup"], args=[], kwargs={})
            core.actor_ref.ask(call, block=True)
            return core

        def start_frontends(self, config, frontend_classes, core):
            logger.info(
                "Starting Mopidy frontends: %s",
                ", ".join(f.__name__ for f in frontend_classes) or "none",
            )

            for frontend_class in frontend_classes:
                with _actor_error_handling(frontend_class.__name__):
                    with timer.time_logger(frontend_class.__name__):
                        frontend_class.start(config=config, core=core)

        def stop_frontends(self, frontend_classes):
            logger.info("Stopping Mopidy frontends")
            for frontend_class in frontend_classes:
                process.stop_actors_by_class(frontend_class)

        def stop_core(self, core):
            logger.info("Stopping Mopidy core")
            if core:
                call = ProxyCall(attr_path=["_teardown"], args=[], kwargs={})
                core.actor_ref.ask(call, block=True)
            process.stop_actors_by_class(Core)

        def stop_backends(self, backend_classes):
            logger.info("Stopping Mopidy backends")
            for backend_class in backend_classes:
                process.stop_actors_by_class(backend_class)

        def stop_audio(self):
            logger.info("Stopping Mopidy audio")
            process.stop_actors_by_class(Audio)

        def stop_mixer(self, mixer_class):
            logger.info("Stopping Mopidy mixer")
            process.stop_actors_by_class(mixer_class)

    class ConfigCommand(Command):
        help = "Show currently active configuration."

        def __init__(self):
            super().__init__()
            self.set(base_verbosity_level=-1)

        def run(self, config, errors, schemas):
            data = config_lib.format(config, schemas, errors)

            # Throw away all bytes that are not valid UTF-8 before printing
            data = data.encode(errors="surrogateescape").decode(errors="replace")

            print(data)
            return 0

    class DepsCommand(Command):
        help = "Show dependencies and debug information."

        def __init__(self):
            super().__init__()
            self.set(base_verbosity_level=-1)

        def run(self):
            print(deps.format_dependency_list())
            return 0