X-Git-Url: https://osm.etsi.org/gitweb/?a=blobdiff_plain;f=juju%2Fclient%2Fconnection.py;h=7457391877e481c1c237e3bdc8c68a8e6cdadd65;hb=eac6d53d640fec2d1adab425c0ce891136b5784b;hp=3011a8adfb2ae307e23ea2dd45cedcbb00990eda;hpb=896db9ff2ab6afeb9756948c771bddae942e2723;p=osm%2FN2VC.git diff --git a/juju/client/connection.py b/juju/client/connection.py index 3011a8a..7457391 100644 --- a/juju/client/connection.py +++ b/juju/client/connection.py @@ -8,18 +8,86 @@ import shlex import ssl import string import subprocess +import weakref import websockets +from concurrent.futures import CancelledError from http.client import HTTPSConnection +from pathlib import Path import asyncio import yaml -from juju import tag -from juju.errors import JujuAPIError, JujuConnectionError +from juju import tag, utils +from juju.client import client +from juju.errors import JujuError, JujuAPIError, JujuConnectionError +from juju.utils import IdQueue log = logging.getLogger("websocket") +class Monitor: + """ + Monitor helper class for our Connection class. + + Contains a reference to an instantiated Connection, along with a + reference to the Connection.receiver Future. Upon inspecttion of + these objects, this class determines whether the connection is in + an 'error', 'connected' or 'disconnected' state. + + Use this class to stay up to date on the health of a connection, + and take appropriate action if the connection errors out due to + network issues or other unexpected circumstances. + + """ + ERROR = 'error' + CONNECTED = 'connected' + DISCONNECTING = 'disconnecting' + DISCONNECTED = 'disconnected' + + def __init__(self, connection): + self.connection = weakref.ref(connection) + self.reconnecting = asyncio.Lock(loop=connection.loop) + self.close_called = asyncio.Event(loop=connection.loop) + self.receiver_stopped = asyncio.Event(loop=connection.loop) + self.pinger_stopped = asyncio.Event(loop=connection.loop) + self.receiver_stopped.set() + self.pinger_stopped.set() + + @property + def status(self): + """ + Determine the status of the connection and receiver, and return + ERROR, CONNECTED, or DISCONNECTED as appropriate. + + For simplicity, we only consider ourselves to be connected + after the Connection class has setup a receiver task. This + only happens after the websocket is open, and the connection + isn't usable until that receiver has been started. + + """ + connection = self.connection() + + # the connection instance was destroyed but someone kept + # a separate reference to the monitor for some reason + if not connection: + return self.DISCONNECTED + + # connection cleanly disconnected or not yet opened + if not connection.ws: + return self.DISCONNECTED + + # close called but not yet complete + if self.close_called.is_set(): + return self.DISCONNECTING + + # connection closed uncleanly (we didn't call connection.close) + if self.receiver_stopped.is_set() or not connection.ws.open: + return self.ERROR + + # everything is fine! + return self.CONNECTED + + class Connection: """ Usage:: @@ -34,28 +102,45 @@ class Connection: # Connect to the currently active model client = await Connection.connect_current() + Note: Any connection method or constructor can accept an optional `loop` + argument to override the default event loop from `asyncio.get_event_loop`. """ + + DEFAULT_FRAME_SIZE = 'default_frame_size' + MAX_FRAME_SIZE = 2**22 + "Maximum size for a single frame. Defaults to 4MB." + def __init__( self, endpoint, uuid, username, password, cacert=None, - macaroons=None, loop=None): + macaroons=None, loop=None, max_frame_size=DEFAULT_FRAME_SIZE): self.endpoint = endpoint + self._endpoint = endpoint self.uuid = uuid - self.username = username - self.password = password - self.macaroons = macaroons + if macaroons: + self.macaroons = macaroons + self.username = '' + self.password = '' + else: + self.macaroons = [] + self.username = username + self.password = password self.cacert = cacert + self._cacert = cacert self.loop = loop or asyncio.get_event_loop() self.__request_id__ = 0 self.addr = None self.ws = None self.facades = {} + self.messages = IdQueue(loop=self.loop) + self.monitor = Monitor(connection=self) + if max_frame_size is self.DEFAULT_FRAME_SIZE: + max_frame_size = self.MAX_FRAME_SIZE + self.max_frame_size = max_frame_size @property def is_open(self): - if self.ws: - return self.ws.open - return False + return self.monitor.status == Monitor.CONNECTED def _get_ssl(self, cert=None): return ssl.create_default_context( @@ -70,19 +155,86 @@ class Connection: kw = dict() kw['ssl'] = self._get_ssl(self.cacert) kw['loop'] = self.loop + kw['max_size'] = self.max_frame_size self.addr = url self.ws = await websockets.connect(url, **kw) + self.loop.create_task(self.receiver()) + self.monitor.receiver_stopped.clear() log.info("Driver connected to juju %s", url) + self.monitor.close_called.clear() return self async def close(self): + if not self.ws: + return + self.monitor.close_called.set() + await self.monitor.pinger_stopped.wait() + await self.monitor.receiver_stopped.wait() await self.ws.close() + self.ws = None - async def recv(self): - result = await self.ws.recv() - if result is not None: - result = json.loads(result) - return result + async def recv(self, request_id): + if not self.is_open: + raise websockets.exceptions.ConnectionClosed(0, 'websocket closed') + return await self.messages.get(request_id) + + async def receiver(self): + try: + while self.is_open: + result = await utils.run_with_interrupt( + self.ws.recv(), + self.monitor.close_called, + loop=self.loop) + if self.monitor.close_called.is_set(): + break + if result is not None: + result = json.loads(result) + await self.messages.put(result['request-id'], result) + except CancelledError: + pass + except websockets.ConnectionClosed as e: + log.warning('Receiver: Connection closed, reconnecting') + await self.messages.put_all(e) + # the reconnect has to be done as a task because the receiver will + # be cancelled by the reconnect and we don't want the reconnect + # to be aborted half-way through + self.loop.create_task(self.reconnect()) + return + except Exception as e: + log.exception("Error in receiver") + # make pending listeners aware of the error + await self.messages.put_all(e) + raise + finally: + self.monitor.receiver_stopped.set() + + async def pinger(self): + ''' + A Controller can time us out if we are silent for too long. This + is especially true in JaaS, which has a fairly strict timeout. + + To prevent timing out, we send a ping every ten seconds. + + ''' + async def _do_ping(): + try: + await pinger_facade.Ping() + await asyncio.sleep(10, loop=self.loop) + except CancelledError: + pass + + pinger_facade = client.PingerFacade.from_connection(self) + try: + while True: + await utils.run_with_interrupt( + _do_ping(), + self.monitor.close_called, + loop=self.loop) + if self.monitor.close_called.is_set(): + break + finally: + self.monitor.pinger_stopped.set() + return async def rpc(self, msg, encoder=None): self.__request_id__ += 1 @@ -92,10 +244,44 @@ class Connection: if "version" not in msg: msg['version'] = self.facades[msg['type']] outgoing = json.dumps(msg, indent=2, cls=encoder) - await self.ws.send(outgoing) - result = await self.recv() - if result and 'error' in result: + for attempt in range(3): + try: + await self.ws.send(outgoing) + break + except websockets.ConnectionClosed: + if attempt == 2: + raise + log.warning('RPC: Connection closed, reconnecting') + # the reconnect has to be done in a separate task because, + # if it is triggered by the pinger, then this RPC call will + # be cancelled when the pinger is cancelled by the reconnect, + # and we don't want the reconnect to be aborted halfway through + await asyncio.wait([self.reconnect()], loop=self.loop) + result = await self.recv(msg['request-id']) + + if not result: + return result + + if 'error' in result: + # API Error Response raise JujuAPIError(result) + + if 'response' not in result: + # This may never happen + return result + + if 'results' in result['response']: + # Check for errors in a result list. + errors = [] + for res in result['response']['results']: + if res.get('error', {}).get('message'): + errors.append(res['error']['message']) + if errors: + raise JujuError(errors) + + elif result['response'].get('error', {}).get('message'): + raise JujuError(result['response']['error']['message']) + return result def http_headers(self): @@ -157,6 +343,7 @@ class Connection: self.cacert, self.macaroons, self.loop, + self.max_frame_size, ) async def controller(self): @@ -173,10 +360,72 @@ class Connection: self.loop, ) + async def _try_endpoint(self, endpoint, cacert): + success = False + result = None + new_endpoints = [] + + self.endpoint = endpoint + self.cacert = cacert + await self.open() + try: + result = await self.login() + if 'discharge-required-error' in result['response']: + log.info('Macaroon discharge required, disconnecting') + else: + # successful login! + log.info('Authenticated') + success = True + except JujuAPIError as e: + if e.error_code != 'redirection required': + raise + log.info('Controller requested redirect') + redirect_info = await self.redirect_info() + redir_cacert = redirect_info['ca-cert'] + new_endpoints = [ + ("{value}:{port}".format(**s), redir_cacert) + for servers in redirect_info['servers'] + for s in servers if s["scope"] == 'public' + ] + finally: + if not success: + await self.close() + return success, result, new_endpoints + + async def reconnect(self): + """ Force a reconnection. + """ + monitor = self.monitor + if monitor.reconnecting.locked() or monitor.close_called.is_set(): + return + async with monitor.reconnecting: + await self.close() + await self._connect() + + async def _connect(self): + endpoints = [(self._endpoint, self._cacert)] + while endpoints: + _endpoint, _cacert = endpoints.pop(0) + success, result, new_endpoints = await self._try_endpoint( + _endpoint, _cacert) + if success: + break + endpoints.extend(new_endpoints) + else: + # ran out of endpoints without a successful login + raise Exception("Couldn't authenticate to {}".format( + self._endpoint)) + + response = result['response'] + self.info = response.copy() + self.build_facades(response.get('facades', {})) + self.loop.create_task(self.pinger()) + self.monitor.pinger_stopped.clear() + @classmethod async def connect( cls, endpoint, uuid, username, password, cacert=None, - macaroons=None, loop=None): + macaroons=None, loop=None, max_frame_size=None): """Connect to the websocket. If uuid is None, the connection will be to the controller. Otherwise it @@ -184,51 +433,28 @@ class Connection: """ client = cls(endpoint, uuid, username, password, cacert, macaroons, - loop) - await client.open() - - redirect_info = await client.redirect_info() - if not redirect_info: - await client.login(username, password, macaroons) - return client - - await client.close() - servers = [ - s for servers in redirect_info['servers'] - for s in servers if s["scope"] == 'public' - ] - for server in servers: - client = cls( - "{value}:{port}".format(**server), uuid, username, - password, redirect_info['ca-cert'], macaroons) - await client.open() - try: - result = await client.login(username, password, macaroons) - if 'discharge-required-error' in result: - continue - return client - except Exception as e: - await client.close() - log.exception(e) - - raise Exception( - "Couldn't authenticate to %s", endpoint) + loop, max_frame_size) + await client._connect() + return client @classmethod - async def connect_current(cls, loop=None): + async def connect_current(cls, loop=None, max_frame_size=None): """Connect to the currently active model. """ jujudata = JujuData() + controller_name = jujudata.current_controller() - models = jujudata.models()[controller_name] - model_name = models['current-model'] + if not controller_name: + raise JujuConnectionError('No current controller') + + model_name = jujudata.current_model() return await cls.connect_model( - '{}:{}'.format(controller_name, model_name), loop) + '{}:{}'.format(controller_name, model_name), loop, max_frame_size) @classmethod - async def connect_current_controller(cls, loop=None): + async def connect_current_controller(cls, loop=None, max_frame_size=None): """Connect to the currently active controller. """ @@ -237,10 +463,12 @@ class Connection: if not controller_name: raise JujuConnectionError('No current controller') - return await cls.connect_controller(controller_name, loop) + return await cls.connect_controller(controller_name, loop, + max_frame_size) @classmethod - async def connect_controller(cls, controller_name, loop=None): + async def connect_controller(cls, controller_name, loop=None, + max_frame_size=None): """Connect to a controller by name. """ @@ -251,45 +479,54 @@ class Connection: accounts = jujudata.accounts()[controller_name] username = accounts['user'] password = accounts.get('password') - macaroons = get_macaroons() if not password else None + macaroons = get_macaroons(controller_name) if not password else None return await cls.connect( - endpoint, None, username, password, cacert, macaroons, loop) + endpoint, None, username, password, cacert, macaroons, loop, + max_frame_size) @classmethod - async def connect_model(cls, model, loop=None): + async def connect_model(cls, model, loop=None, max_frame_size=None): """Connect to a model by name. - :param str model: : + :param str model: [:] """ - controller_name, model_name = model.split(':') - jujudata = JujuData() + + if ':' in model: + # explicit controller given + controller_name, model_name = model.split(':') + else: + # use the current controller if one isn't explicitly given + controller_name = jujudata.current_controller() + model_name = model + + accounts = jujudata.accounts()[controller_name] + username = accounts['user'] + # model name must include a user prefix, so add it if it doesn't + if '/' not in model_name: + model_name = '{}/{}'.format(username, model_name) + controller = jujudata.controllers()[controller_name] endpoint = controller['api-endpoints'][0] cacert = controller.get('ca-cert') - accounts = jujudata.accounts()[controller_name] - username = accounts['user'] password = accounts.get('password') models = jujudata.models()[controller_name] - model_name = '{}/{}'.format(username, model_name) model_uuid = models['models'][model_name]['uuid'] - macaroons = get_macaroons() if not password else None + macaroons = get_macaroons(controller_name) if not password else None return await cls.connect( - endpoint, model_uuid, username, password, cacert, macaroons, loop) + endpoint, model_uuid, username, password, cacert, macaroons, loop, + max_frame_size) - def build_facades(self, info): + def build_facades(self, facades): self.facades.clear() - for facade in info: + for facade in facades: self.facades[facade['name']] = facade['versions'][-1] - async def login(self, username, password, macaroons=None): - if macaroons: - username = '' - password = '' - + async def login(self): + username = self.username if username and not username.startswith('user-'): username = 'user-{}'.format(username) @@ -299,14 +536,11 @@ class Connection: "version": 3, "params": { "auth-tag": username, - "credentials": password, + "credentials": self.password, "nonce": "".join(random.sample(string.printable, 12)), - "macaroons": macaroons or [] + "macaroons": self.macaroons }}) - response = result['response'] - self.build_facades(response.get('facades', {})) - self.info = response.copy() - return response + return result async def redirect_info(self): try: @@ -333,6 +567,14 @@ class JujuData: output = yaml.safe_load(output) return output.get('current-controller', '') + def current_model(self, controller_name=None): + if not controller_name: + controller_name = self.current_controller() + models = self.models()[controller_name] + if 'current-model' not in models: + raise JujuError('No current model') + return models['current-model'] + def controllers(self): return self._load_yaml('controllers.yaml', 'controllers') @@ -348,16 +590,26 @@ class JujuData: return yaml.safe_load(f)[key] -def get_macaroons(): +def get_macaroons(controller_name=None): """Decode and return macaroons from default ~/.go-cookies """ - try: - cookie_file = os.path.expanduser('~/.go-cookies') - with open(cookie_file, 'r') as f: - cookies = json.load(f) - except (OSError, ValueError): - log.warn("Couldn't load macaroons from %s", cookie_file) + cookie_files = [] + if controller_name: + cookie_files.append('~/.local/share/juju/cookies/{}.json'.format( + controller_name)) + cookie_files.append('~/.go-cookies') + for cookie_file in cookie_files: + cookie_file = Path(cookie_file).expanduser() + if cookie_file.exists(): + try: + cookies = json.loads(cookie_file.read_text()) + break + except (OSError, ValueError): + log.warn("Couldn't load macaroons from %s", cookie_file) + return [] + else: + log.warn("Couldn't load macaroons from %s", ' or '.join(cookie_files)) return [] base64_macaroons = [