12 from ws4py.client.threadedclient import WebSocketClient
14 _logger = logging.getLogger('arvados.events')
16 class EventClient(WebSocketClient):
17 def __init__(self, url, filters, on_event, last_log_id):
18 ssl_options = {'ca_certs': arvados.util.ca_certs_path()}
19 if config.flag_is_true('ARVADOS_API_HOST_INSECURE'):
20 ssl_options['cert_reqs'] = ssl.CERT_NONE
22 ssl_options['cert_reqs'] = ssl.CERT_REQUIRED
24 # Warning: If the host part of url resolves to both IPv6 and
25 # IPv4 addresses (common with "localhost"), only one of them
26 # will be attempted -- and it might not be the right one. See
27 # ws4py's WebSocketBaseClient.__init__.
28 super(EventClient, self).__init__(url, ssl_options=ssl_options)
29 self.filters = filters
30 self.on_event = on_event
31 self.last_log_id = last_log_id
34 self.subscribe(self.filters, self.last_log_id)
36 def received_message(self, m):
37 self.on_event(json.loads(str(m)))
39 def close_connection(self):
41 self.sock.shutdown(socket.SHUT_RDWR)
46 def subscribe(self, filters, last_log_id=None):
47 m = {"method": "subscribe", "filters": filters}
48 if last_log_id is not None:
49 m["last_log_id"] = last_log_id
50 self.send(json.dumps(m))
52 def unsubscribe(self, filters):
53 self.send(json.dumps({"method": "unsubscribe", "filters": filters}))
55 class PollClient(threading.Thread):
56 def __init__(self, api, filters, on_event, poll_time, last_log_id):
57 super(PollClient, self).__init__()
60 self.filters = [filters]
63 self.on_event = on_event
64 self.poll_time = poll_time
66 self.stop = threading.Event()
67 self.last_log_id = last_log_id
71 if self.last_log_id != None:
72 self.id = self.last_log_id
74 for f in self.filters:
75 items = self.api.logs().list(limit=1, order="id desc", filters=f).execute()['items']
77 if items[0]['id'] > self.id:
78 self.id = items[0]['id']
80 self.on_event({'status': 200})
82 while not self.stop.isSet():
84 for f in self.filters:
85 items = self.api.logs().list(order="id asc", filters=f+[["id", ">", str(self.id)]]).execute()['items']
91 self.stop.wait(self.poll_time)
93 def run_forever(self):
94 # Have to poll here, otherwise KeyboardInterrupt will never get processed.
95 while not self.stop.is_set():
103 # "join() raises a RuntimeError if an attempt is made to join the
104 # current thread as that would cause a deadlock. It is also an
105 # error to join() a thread before it has been started and attempts
106 # to do so raises the same exception."
109 def subscribe(self, filters):
110 self.on_event({'status': 200})
111 self.filters.append(filters)
113 def unsubscribe(self, filters):
114 del self.filters[self.filters.index(filters)]
117 def _subscribe_websocket(api, filters, on_event, last_log_id=None):
118 endpoint = api._rootDesc.get('websocketUrl', None)
120 raise errors.FeatureNotEnabledError(
121 "Server does not advertise a websocket endpoint")
122 uri_with_token = "{}?api_token={}".format(endpoint, api.api_token)
123 client = EventClient(uri_with_token, filters, on_event, last_log_id)
131 client.close_connection()
133 def subscribe(api, filters, on_event, poll_fallback=15, last_log_id=None):
136 a client object retrieved from arvados.api(). The caller should not use this client object for anything else after calling subscribe().
138 Initial subscription filters.
140 The callback when a message is received.
142 If websockets are not available, fall back to polling every N seconds. If poll_fallback=False, this will return None if websockets are not available.
144 Log rows that are newer than the log id
147 if not poll_fallback:
148 return _subscribe_websocket(api, filters, on_event, last_log_id)
151 return _subscribe_websocket(api, filters, on_event, last_log_id)
152 except Exception as e:
153 _logger.warn("Falling back to polling after websocket error: %s" % e)
154 p = PollClient(api, filters, on_event, poll_fallback, last_log_id)