+# Copyright (C) The Arvados Authors. All rights reserved.
+#
+# SPDX-License-Identifier: Apache-2.0
+
+from __future__ import absolute_import
+from future import standard_library
+standard_library.install_aliases()
+from builtins import str
+from builtins import object
import arvados
-import config
-import errors
+from . import config
+from . import errors
+from .retry import RetryLoop
import logging
import json
+import _thread
import threading
import time
import os
_logger = logging.getLogger('arvados.events')
-class EventClient(WebSocketClient):
- def __init__(self, url, filters, on_event, last_log_id):
+
+class _EventClient(WebSocketClient):
+ def __init__(self, url, filters, on_event, last_log_id, on_closed):
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
# 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)
+ 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
+ self._closing_lock = threading.RLock()
+ self._closing = False
+ self._closed = threading.Event()
+ self.on_closed = on_closed
def opened(self):
- self.subscribe(self.filters, self.last_log_id)
-
- def received_message(self, m):
- self.on_event(json.loads(str(m)))
+ for f in self.filters:
+ self.subscribe(f, self.last_log_id)
def closed(self, code, reason=None):
- self.stop.set()
+ self._closed.set()
+ self.on_closed()
- def close(self, code=1000, reason=''):
- """Close event client and wait for it to finish."""
-
- # parent close() method sends a asynchronous "closed" event to the server
- super(EventClient, self).close(code, reason)
+ def received_message(self, m):
+ with self._closing_lock:
+ if not self._closing:
+ self.on_event(json.loads(str(m)))
- # 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()
+ def close(self, code=1000, reason='', timeout=0):
+ """Close event client and optionally wait for it to finish.
- # 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)
+ :timeout: is the number of seconds to wait for ws4py to
+ indicate that the connection has closed.
+ """
+ super(_EventClient, self).close(code, reason)
+ with self._closing_lock:
+ # make sure we don't process any more messages.
+ self._closing = True
+ # wait for ws4py to tell us the connection is closed.
+ self._closed.wait(timeout=timeout)
- def subscribe(self, filters, last_log_id=None):
- m = {"method": "subscribe", "filters": filters}
+ def subscribe(self, f, last_log_id=None):
+ m = {"method": "subscribe", "filters": f}
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}))
+ def unsubscribe(self, f):
+ self.send(json.dumps({"method": "unsubscribe", "filters": f}))
+
+
+class EventClient(object):
+ def __init__(self, url, filters, on_event_cb, last_log_id):
+ self.url = url
+ if filters:
+ self.filters = [filters]
+ else:
+ self.filters = [[]]
+ self.on_event_cb = on_event_cb
+ self.last_log_id = last_log_id
+ self.is_closed = threading.Event()
+ self._setup_event_client()
+
+ def _setup_event_client(self):
+ self.ec = _EventClient(self.url, self.filters, self.on_event,
+ self.last_log_id, self.on_closed)
+ self.ec.daemon = True
+ try:
+ self.ec.connect()
+ except Exception:
+ self.ec.close_connection()
+ raise
+
+ def subscribe(self, f, last_log_id=None):
+ self.filters.append(f)
+ self.ec.subscribe(f, last_log_id)
+
+ def unsubscribe(self, f):
+ del self.filters[self.filters.index(f)]
+ self.ec.unsubscribe(f)
+
+ def close(self, code=1000, reason='', timeout=0):
+ self.is_closed.set()
+ self.ec.close(code, reason, timeout)
+
+ def on_event(self, m):
+ if m.get('id') != None:
+ self.last_log_id = m.get('id')
+ try:
+ self.on_event_cb(m)
+ except Exception as e:
+ _logger.exception("Unexpected exception from event callback.")
+ _thread.interrupt_main()
+
+ def on_closed(self):
+ if not self.is_closed.is_set():
+ _logger.warning("Unexpected close. Reconnecting.")
+ for tries_left in RetryLoop(num_retries=25, backoff_start=.1, max_wait=15):
+ try:
+ self._setup_event_client()
+ _logger.warning("Reconnect successful.")
+ break
+ except Exception as e:
+ _logger.warning("Error '%s' during websocket reconnect.", e)
+ if tries_left == 0:
+ _logger.exception("EventClient thread could not contact websocket server.")
+ self.is_closed.set()
+ _thread.interrupt_main()
+ return
+
+ def run_forever(self):
+ # Have to poll here to let KeyboardInterrupt get raised.
+ while not self.is_closed.wait(1):
+ pass
+
class PollClient(threading.Thread):
def __init__(self, api, filters, on_event, poll_time, last_log_id):
self.on_event = on_event
self.poll_time = poll_time
self.daemon = True
- self.stop = threading.Event()
self.last_log_id = last_log_id
+ self._closing = threading.Event()
+ self._closing_lock = threading.RLock()
def run(self):
- self.id = 0
if self.last_log_id != None:
- self.id = self.last_log_id
+ # Caller supplied the last-seen event ID from a previous
+ # connection
+ skip_old_events = [["id", ">", str(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']
+ # We need to do a reverse-order query to find the most
+ # recent event ID (see "if not skip_old_events" below).
+ skip_old_events = False
self.on_event({'status': 200})
- while not self.stop.isSet():
- max_id = self.id
+ while not self._closing.is_set():
moreitems = False
for f in self.filters:
- items = self.api.logs().list(order="id asc", filters=f+[["id", ">", str(self.id)]]).execute()
+ for tries_left in RetryLoop(num_retries=25, backoff_start=.1, max_wait=self.poll_time):
+ try:
+ if not skip_old_events:
+ # If the caller didn't provide a known
+ # recent ID, our first request will ask
+ # for the single most recent event from
+ # the last 2 hours (the time restriction
+ # avoids doing an expensive database
+ # query, and leaves a big enough margin to
+ # account for clock skew). If we do find a
+ # recent event, we remember its ID but
+ # then discard it (we are supposed to be
+ # returning new/current events, not old
+ # ones).
+ #
+ # Subsequent requests will get multiple
+ # events in chronological order, and
+ # filter on that same cutoff time, or
+ # (once we see our first matching event)
+ # the ID of the last-seen event.
+ skip_old_events = [[
+ "created_at", ">=",
+ time.strftime(
+ "%Y-%m-%dT%H:%M:%SZ",
+ time.gmtime(time.time()-7200))]]
+ items = self.api.logs().list(
+ order="id desc",
+ limit=1,
+ filters=f+skip_old_events).execute()
+ if items["items"]:
+ skip_old_events = [
+ ["id", ">", str(items["items"][0]["id"])]]
+ items = {
+ "items": [],
+ "items_available": 0,
+ }
+ else:
+ # In this case, either we know the most
+ # recent matching ID, or we know there
+ # were no matching events in the 2-hour
+ # window before subscribing. Either way we
+ # can safely ask for events in ascending
+ # order.
+ items = self.api.logs().list(
+ order="id asc",
+ filters=f+skip_old_events).execute()
+ break
+ except errors.ApiError as error:
+ pass
+ else:
+ tries_left = 0
+ break
+ if tries_left == 0:
+ _logger.exception("PollClient thread could not contact API server.")
+ with self._closing_lock:
+ self._closing.set()
+ _thread.interrupt_main()
+ return
for i in items["items"]:
- if i['id'] > max_id:
- max_id = i['id']
- self.on_event(i)
+ skip_old_events = [["id", ">", str(i["id"])]]
+ with self._closing_lock:
+ if self._closing.is_set():
+ return
+ try:
+ self.on_event(i)
+ except Exception as e:
+ _logger.exception("Unexpected exception from event callback.")
+ _thread.interrupt_main()
if items["items_available"] > len(items["items"]):
moreitems = True
- self.id = max_id
if not moreitems:
- self.stop.wait(self.poll_time)
+ self._closing.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)
+ while not self._closing.is_set():
+ self._closing.wait(1)
+
+ def close(self, code=None, reason=None, timeout=0):
+ """Close poll client and optionally wait for it to finish.
+
+ If an :on_event: handler is running in a different thread,
+ first wait (indefinitely) for it to return.
- def close(self):
- """Close poll client and wait for it to finish."""
+ After closing, wait up to :timeout: seconds for the thread to
+ finish the poll request in progress (if any).
- self.stop.set()
+ :code: and :reason: are ignored. They are present for
+ interface compatibility with EventClient.
+ """
+
+ with self._closing_lock:
+ self._closing.set()
try:
- self.join()
+ self.join(timeout=timeout)
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
# to do so raises the same exception."
pass
- def subscribe(self, filters):
+ def subscribe(self, f):
self.on_event({'status': 200})
- self.filters.append(filters)
+ self.filters.append(f)
- def unsubscribe(self, filters):
- del self.filters[self.filters.index(filters)]
+ def unsubscribe(self, f):
+ del self.filters[self.filters.index(f)]
def _subscribe_websocket(api, filters, on_event, last_log_id=None):
if not endpoint:
raise errors.FeatureNotEnabledError(
"Server does not advertise a websocket endpoint")
+ uri_with_token = "{}?api_token={}".format(endpoint, api.api_token)
try:
- 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()
- except:
- _logger.warn("Failed to connect to websockets on %s" % endpoint)
+ except Exception:
+ _logger.warning("Failed to connect to websockets on %s" % endpoint)
raise
+ else:
+ return client
def subscribe(api, filters, on_event, poll_fallback=15, last_log_id=None):
return _subscribe_websocket(api, filters, on_event, last_log_id)
try:
- return _subscribe_websocket(api, filters, on_event, last_log_id)
+ if not config.flag_is_true('ARVADOS_DISABLE_WEBSOCKETS'):
+ return _subscribe_websocket(api, filters, on_event, last_log_id)
+ else:
+ _logger.info("Using polling because ARVADOS_DISABLE_WEBSOCKETS is true")
except Exception as e:
- _logger.warn("Falling back to polling after websocket error: %s" % e)
+ _logger.warning("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