- ws = None
- if 'websocketUrl' in api._rootDesc:
- try:
- url = "{}?api_token={}".format(api._rootDesc['websocketUrl'], api.api_token)
- ws = EventClient(url, filters, on_event)
- ws.connect()
- return ws
- except Exception as e:
- _logger.warn("Got exception %s trying to connect to web sockets" % e)
- if ws:
- ws.close()
- if poll_fallback:
- _logger.warn("Web sockets not available, falling back to log table polling")
- p = PollClient(api, filters, on_event, poll_fallback)
- p.start()
- return p
- else:
- _logger.error("Web sockets not available")
- return None
+ """
+ :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:
+ 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