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Adds the following: - daemonie(), start_daemon(), stop_daemon() utility funcs. - RPC service app constructor and service daemon. - SPaaS Service Stack daemon - Entrypoints for the SPaaS stack and the SPaaS RPC daemons.
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Aug 9, 2019
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -1,96 +1,50 @@ | ||
| import multiprocessing as mp | ||
| import logging | ||
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| import requests | ||
| import structlog | ||
| import waitress | ||
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| from scenario_player.exceptions.services import ServiceProcessException | ||
| from scenario_player.services.utils.factories import construct_flask_app | ||
| from scenario_player.services.utils.factories import ( | ||
| construct_flask_app, | ||
| default_service_daemon_cli, | ||
| start_daemon, | ||
| stop_daemon, | ||
| ) | ||
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| log = structlog.getLogger(__name__) | ||
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| class ServiceProcess(mp.Process): | ||
| """:class:`multiprocessing.Process` subclass for running the SP services. | ||
| def serve_spaas_stack(logfile_path, host, port): | ||
| """Run an RPC flask app as a daemonized process.""" | ||
| logging.basicConfig(filename=logfile_path, filemode="a+", level=logging.DEBUG) | ||
| log = structlog.getLogger() | ||
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| The class's :meth:`.stop` method checks the server status and shuts it down | ||
| via a POST request. | ||
| app = construct_flask_app() | ||
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| Instances of this class have their :attr:`.daemon` attribute **always** set | ||
| to `True`, regardless of any keywords passed to the class constructor. | ||
| It can only be overridden by setting it after class initialization. | ||
| log.info("Starting SPaaS Service Stack", host=host, port=port) | ||
| waitress.serve(app, host=host, port=port) | ||
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| Should the service not be reachable, it calls :meth:`.kill` instead, since | ||
| the assumption is that it is stuck in a deadlock. | ||
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| Also offers a :func:`.app_is_responsive` property, which returns a boolean. | ||
| This return `True` if a `GET /status` request returns a response (the status | ||
| code does not matter) and `False` if a connection error or timeout occurred. | ||
| """ | ||
| def service_daemon(): | ||
| parser = default_service_daemon_cli() | ||
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| def __init__(self, *args, host: str = "127.0.0.1", port: int = 5000, **kwargs): | ||
| if "target" in kwargs: | ||
| raise ValueError("'target' is not supported by this class!") | ||
| super(ServiceProcess, self).__init__(*args, **kwargs) | ||
| self.daemon = True | ||
| self.host = host | ||
| self.port = port | ||
| args = parser.parse_args() | ||
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| @property | ||
| def is_reachable(self) -> bool: | ||
| try: | ||
| requests.get(f"http://{self.host}:{self.port}/status") | ||
| except (requests.ConnectionError, requests.Timeout): | ||
| # The service does not appear to be reachable. | ||
| return False | ||
| else: | ||
| return True | ||
| logfile_path = args.raiden_dir.joinpath("spaas") | ||
| logfile_path.mkdir(exist_ok=True, parents=True) | ||
| logfile_path = logfile_path.joinpath("SPaaS-Stack.log") | ||
| logfile_path.touch() | ||
|
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| def stop(self) -> None: | ||
| """Gracefully stop the service, if possible. Otherwise, kill it. | ||
| PIDFILE = args.raiden_dir.joinpath("spaas", "service-stack.pid") | ||
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| This depends on if and how the Service's `/shutdown` endpoint responds. | ||
| If we cannot connect to it, or our request times out, we assume the service | ||
| is dead in the water and kill it. | ||
| If we do get a response, but its status code is not in the `2xx` range, | ||
| we check if the service is otherwise working, by making a GET request to | ||
| the `/status` endpoint. If this does succeed, we must assume the | ||
| shutdown sequence is faulty, and raise a :exc:`ServiceProcessException`. | ||
| .. Note:: | ||
| In order for this method to work correctly, it requires the | ||
| :var:`scenario_player.services.common.blueprints.admin_blueprint` | ||
| to be registered with the app to gracefully shut it down. | ||
| Should the blueprint not be registered, it will *always* call :meth:`.kill`. | ||
| :raises ServiceProcessException: if we failed to shut down the service. | ||
| """ | ||
| shutdown_type = "werkzeug.server.shutdown" | ||
| try: | ||
| resp = requests.post(f"http://{self.host}:{self.port}/shutdown") | ||
| except (requests.ConnectionError, requests.Timeout): | ||
| # The server is not responding. Kill it with a hammer. | ||
| shutdown_type = "SIGKILL" | ||
| return self.kill() | ||
| else: | ||
| try: | ||
| resp.raise_for_status() | ||
| except requests.HTTPError: | ||
| if self.is_reachable: | ||
| # The server doesn't want to play ball - "gently" terminate its ass. | ||
| shutdown_type = "SIGTERM" | ||
| self.terminate() | ||
| finally: | ||
| if self.is_reachable: | ||
| # The server still exists.Notify a human about its insubordinantion. | ||
| raise ServiceProcessException("Shutdown sequence could not be initialized!") | ||
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| log.info("SPaaS Server shutdown", shutdown_type=shutdown_type) | ||
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| def run(self): | ||
| """Run the Service.""" | ||
| app = construct_flask_app() | ||
| waitress.serve(app, host=self.host, port=self.port) | ||
| if args.command == "start": | ||
| start_daemon( | ||
| PIDFILE, | ||
| serve_spaas_stack, | ||
| logfile_path, | ||
| args.host, | ||
| args.port, | ||
| stdout=logfile_path, | ||
| stderr=logfile_path, | ||
| ) | ||
| elif args.command == "stop": | ||
| stop_daemon(PIDFILE) |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,88 @@ | ||
| """Utility script to run an RPC Service instance from the command line. | ||
| TODO: Actually make use of the `--log-service` argument and configure | ||
| logging accordingly, if given. | ||
| """ | ||
| import logging | ||
| import pathlib | ||
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| import flask | ||
| import structlog | ||
| import waitress | ||
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| from scenario_player.services.common.blueprints import admin_blueprint, metrics_blueprint | ||
| from scenario_player.services.rpc.blueprints import ( | ||
| instances_blueprint, | ||
| tokens_blueprint, | ||
| transactions_blueprint, | ||
| ) | ||
| from scenario_player.services.rpc.utils import RPCRegistry | ||
| from scenario_player.services.utils.factories import ( | ||
| default_service_daemon_cli, | ||
| start_daemon, | ||
| stop_daemon, | ||
| ) | ||
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| def rpc_app(): | ||
| """Create a :mod:`flask` app using only the RPC blueprints.""" | ||
| from scenario_player import __version__ | ||
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| log = logging.getLogger() | ||
| NAME = "SPaaS-RPC-Service" | ||
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| log.info("Creating RPC Flask App", version=__version__, name=NAME) | ||
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| app = flask.Flask(NAME) | ||
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| log.debug("Creating RPC Client Registry") | ||
| app.config["rpc-client"] = RPCRegistry() | ||
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| blueprints = [ | ||
| admin_blueprint, | ||
| instances_blueprint, | ||
| metrics_blueprint, | ||
| tokens_blueprint, | ||
| transactions_blueprint, | ||
| ] | ||
| for bp in blueprints: | ||
| log.debug("Registering blueprint", blueprint=bp.name) | ||
| app.register_blueprint(bp) | ||
| return app | ||
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| def serve_rpc(logfile_path, host, port): | ||
| """Run an RPC flask app as a daemonized process.""" | ||
| logging.basicConfig(filename=logfile_path, filemode="a+", level=logging.DEBUG) | ||
| log = structlog.getLogger() | ||
|
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| app = rpc_app() | ||
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| log.info("Starting RPC Service", host=host, port=port) | ||
| waitress.serve(app, host=host, port=port) | ||
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| def service_daemon(): | ||
| parser = default_service_daemon_cli() | ||
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| args = parser.parse_args() | ||
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| logfile_path = args.raiden_dir.joinpath("spaas") | ||
| logfile_path.mkdir(exist_ok=True, parents=True) | ||
| logfile_path = logfile_path.joinpath("SPaaS-RPC.log") | ||
| logfile_path.touch() | ||
|
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| PIDFILE = args.raiden_dir.joinpath("spaas", "rpc-service.pid") | ||
|
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| if args.command == "start": | ||
| start_daemon( | ||
| PIDFILE, | ||
| serve_rpc, | ||
| logfile_path, | ||
| args.host, | ||
| args.port, | ||
| stdout=logfile_path, | ||
| stderr=logfile_path, | ||
| ) | ||
| elif args.command == "stop": | ||
| stop_daemon(PIDFILE) |
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