-from ws4py.client.threadedclient import WebSocketClient
-import thread
+import arvados
+import config
+import errors
+
+import logging
import json
-import os
+import threading
import time
-import ssl
+import os
import re
-import config
-import logging
+import ssl
+from ws4py.client.threadedclient import WebSocketClient
_logger = logging.getLogger('arvados.events')
class EventClient(WebSocketClient):
def __init__(self, url, filters, on_event):
- ssl_options = None
- if re.match(r'(?i)^(true|1|yes)$',
- config.get('ARVADOS_API_HOST_INSECURE', 'no')):
- ssl_options={'cert_reqs': ssl.CERT_NONE}
+ # Prefer system's CA certificates (if available)
+ ssl_options = {}
+ certs_path = '/etc/ssl/certs/ca-certificates.crt'
+ if os.path.exists(certs_path):
+ ssl_options['ca_certs'] = certs_path
+ if config.flag_is_true('ARVADOS_API_HOST_INSECURE'):
+ ssl_options['cert_reqs'] = ssl.CERT_NONE
else:
- ssl_options={'cert_reqs': ssl.CERT_REQUIRED}
+ ssl_options['cert_reqs'] = ssl.CERT_REQUIRED
- super(EventClient, self).__init__(url, ssl_options)
+ # Warning: If the host part of url resolves to both IPv6 and
+ # IPv4 addresses (common with "localhost"), only one of them
+ # will be attempted -- and it might not be the right one. See
+ # ws4py's WebSocketBaseClient.__init__.
+ super(EventClient, self).__init__(url, ssl_options=ssl_options)
self.filters = filters
self.on_event = on_event
def opened(self):
- self.send(json.dumps({"method": "subscribe", "filters": self.filters}))
+ self.subscribe(self.filters)
def received_message(self, m):
self.on_event(json.loads(str(m)))
except:
pass
-def subscribe(api, filters, on_event):
- ws = None
+ def subscribe(self, filters, last_log_id=None):
+ m = {"method": "subscribe", "filters": filters}
+ if last_log_id is not None:
+ m["last_log_id"] = last_log_id
+ self.send(json.dumps(m))
+
+ def unsubscribe(self, filters):
+ self.send(json.dumps({"method": "unsubscribe", "filters": filters}))
+
+class PollClient(threading.Thread):
+ def __init__(self, api, filters, on_event, poll_time):
+ super(PollClient, self).__init__()
+ self.api = api
+ if filters:
+ self.filters = [filters]
+ else:
+ self.filters = [[]]
+ self.on_event = on_event
+ self.poll_time = poll_time
+ self.daemon = True
+ self.stop = threading.Event()
+
+ def run(self):
+ self.id = 0
+ for f in self.filters:
+ items = self.api.logs().list(limit=1, order="id desc", filters=f).execute()['items']
+ if items:
+ if items[0]['id'] > self.id:
+ self.id = items[0]['id']
+
+ self.on_event({'status': 200})
+
+ while not self.stop.isSet():
+ max_id = self.id
+ for f in self.filters:
+ items = self.api.logs().list(order="id asc", filters=f+[["id", ">", str(self.id)]]).execute()['items']
+ for i in items:
+ if i['id'] > max_id:
+ max_id = i['id']
+ self.on_event(i)
+ self.id = max_id
+ self.stop.wait(self.poll_time)
+
+ def run_forever(self):
+ # Have to poll here, otherwise KeyboardInterrupt will never get processed.
+ while not self.stop.is_set():
+ self.stop.wait(1)
+
+ def close(self):
+ self.stop.set()
+ try:
+ self.join()
+ except RuntimeError:
+ # "join() raises a RuntimeError if an attempt is made to join the
+ # current thread as that would cause a deadlock. It is also an
+ # error to join() a thread before it has been started and attempts
+ # to do so raises the same exception."
+ pass
+
+ def subscribe(self, filters):
+ self.on_event({'status': 200})
+ self.filters.append(filters)
+
+ def unsubscribe(self, filters):
+ del self.filters[self.filters.index(filters)]
+
+
+def _subscribe_websocket(api, filters, on_event):
+ endpoint = api._rootDesc.get('websocketUrl', None)
+ if not endpoint:
+ raise errors.FeatureNotEnabledError(
+ "Server does not advertise a websocket endpoint")
+ uri_with_token = "{}?api_token={}".format(endpoint, api.api_token)
+ client = EventClient(uri_with_token, filters, on_event)
+ ok = False
+ try:
+ client.connect()
+ ok = True
+ return client
+ finally:
+ if not ok:
+ client.close_connection()
+
+def subscribe(api, filters, on_event, poll_fallback=15):
+ """
+ :api:
+ a client object retrieved from arvados.api(). The caller should not use this client object for anything else after calling subscribe().
+ :filters:
+ Initial subscription filters.
+ :on_event:
+ The callback when a message is received.
+ :poll_fallback:
+ 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.
+ """
+
+ if not poll_fallback:
+ return _subscribe_websocket(api, filters, on_event)
+
try:
- url = "{}?api_token={}".format(api._rootDesc['websocketUrl'], config.get('ARVADOS_API_TOKEN'))
- ws = EventClient(url, filters, on_event)
- ws.connect()
- return ws
- except Exception:
- if (ws):
- ws.close_connection()
- raise
+ return _subscribe_websocket(api, filters, on_event)
+ except Exception as e:
+ _logger.warn("Falling back to polling after websocket error: %s" % e)
+ p = PollClient(api, filters, on_event, poll_fallback)
+ p.start()
+ return p
projects / arvados.git / blobdiff