import re
import config
import logging
+import arvados
_logger = logging.getLogger('arvados.events')
def __init__(self, api, filters, on_event, poll_time):
super(PollClient, self).__init__()
self.api = api
- self.filters = filters
- self.on_event = on_event
- items = self.api.logs().list(limit=1, order=["id desc"], filters=filters).execute()['items']
- if len(items) > 0:
- self.id = items[0]["id"]
+ if filters:
+ self.filters = [filters]
else:
- self.id = 0
+ self.filters = [[]]
+ self.on_event = on_event
self.poll_time = poll_time
- self.loop = True
- self.on_event({'status': 200})
+ self.stop = threading.Event()
def run(self):
- while self.loop:
- time.sleep(self.poll_time)
- items = self.api.logs().list(order=["id asc"], filters=self.filters+[["id", ">", str(self.id)]]).execute()['items']
- for i in items:
- self.id = i['id']
- self.on_event(i)
+ 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 close(self):
- self.loop = False
+ self.stop.set()
self.join()
def subscribe(self, filters):
self.on_event({'status': 200})
- self.filters += filters
+ self.filters.append(filters)
def unsubscribe(self, filters):
del self.filters[self.filters.index(filters)]
+
def subscribe(api, filters, on_event, poll_fallback=15):
+ '''
+ api: Must be a newly created from arvados.api(cache=False), not shared with the caller, as it may be used by a background thread.
+ 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.
+ '''
ws = None
if 'websocketUrl' in api._rootDesc:
try:
ws.connect()
return ws
except Exception as e:
- _logger.warn("Got exception %s trying to connect to web sockets" % e)
+ _logger.warn("Got exception %s trying to connect to websockets at %s" % (e, api._rootDesc['websocketUrl']))
if ws:
- ws.close()
+ ws.close_connection()
if poll_fallback:
- _logger.warn("Web sockets not available, falling back to log table polling")
+ _logger.warn("Websockets 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")
+ _logger.error("Websockets not available")
return None