-from ws4py.client.threadedclient import WebSocketClient
-import threading
+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 arvados
+import ssl
+from ws4py.client.threadedclient import WebSocketClient
_logger = logging.getLogger('arvados.events')
class EventClient(WebSocketClient):
- def __init__(self, url, filters, on_event):
- # 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
+ def __init__(self, url, filters, on_event, last_log_id):
+ ssl_options = {'ca_certs': arvados.util.ca_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
+
+ # 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
+ self.stop = threading.Event()
+ self.last_log_id = last_log_id
def opened(self):
- self.subscribe(self.filters)
+ self.subscribe(self.filters, self.last_log_id)
def received_message(self, m):
self.on_event(json.loads(str(m)))
- def close_connection(self):
- try:
- self.sock.shutdown(socket.SHUT_RDWR)
- self.sock.close()
- except:
- pass
+ def closed(self, code, reason=None):
+ self.stop.set()
+
+ def close(self, code=1000, reason=''):
+ # parent close() method sends a asynchronous "closed" event to the server
+ super(EventClient, self).close(code, reason)
+
+ # if server doesn't respond by finishing the close handshake, we'll be
+ # stuck in limbo forever. We don't need to wait for the server to
+ # respond to go ahead and actually close the socket.
+ self.close_connection()
+
+ # wait for websocket thread to finish up (closed() is called by
+ # websocket thread in as part of terminate())
+ while not self.stop.is_set():
+ self.stop.wait(1)
def subscribe(self, filters, last_log_id=None):
m = {"method": "subscribe", "filters": filters}
self.send(json.dumps({"method": "unsubscribe", "filters": filters}))
class PollClient(threading.Thread):
- def __init__(self, api, filters, on_event, poll_time):
+ def __init__(self, api, filters, on_event, poll_time, last_log_id):
super(PollClient, self).__init__()
self.api = api
if filters:
self.filters = [[]]
self.on_event = on_event
self.poll_time = poll_time
+ self.daemon = True
self.stop = threading.Event()
+ self.last_log_id = last_log_id
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']
+ if self.last_log_id != None:
+ self.id = self.last_log_id
+ else:
+ 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})
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:
- 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 websockets at %s" % (e, api._rootDesc['websocketUrl']))
- if ws:
- ws.close_connection()
- if poll_fallback:
- _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("Websockets not available")
- return None
+def _subscribe_websocket(api, filters, on_event, last_log_id=None):
+ 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, last_log_id)
+ 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, last_log_id=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.
+ :last_log_id:
+ Log rows that are newer than the log id
+ """
+
+ if not poll_fallback:
+ return _subscribe_websocket(api, filters, on_event, last_log_id)
+
+ try:
+ return _subscribe_websocket(api, filters, on_event, last_log_id)
+ except Exception as e:
+ _logger.warn("Falling back to polling after websocket error: %s" % e)
+ p = PollClient(api, filters, on_event, poll_fallback, last_log_id)
+ p.start()
+ return p
projects / arvados.git / blobdiff