X-Git-Url: https://git.arvados.org/arvados.git/blobdiff_plain/245c6abec4bf824ad8c8683e59ab6ee08c836cf7..6e5e1c725a10ea791f00d073003175ac3c29a6c7:/sdk/python/arvados/events.py diff --git a/sdk/python/arvados/events.py b/sdk/python/arvados/events.py index 4570cc0d15..b1872002eb 100644 --- a/sdk/python/arvados/events.py +++ b/sdk/python/arvados/events.py @@ -1,30 +1,37 @@ -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): - 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} + 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} + 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.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))) @@ -52,22 +59,24 @@ class PollClient(threading.Thread): if filters: self.filters = [filters] else: - self.filters = [] + self.filters = [[]] self.on_event = on_event self.poll_time = poll_time + self.daemon = True self.stop = threading.Event() def run(self): - items = self.api.logs().list(limit=1, order="id desc", filters=self.filters[0]).execute()['items'] - if len(items) > 0: - self.id = items[0]["id"] - else: - self.id = 0 + 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 = 0 + 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: @@ -77,9 +86,21 @@ class PollClient(threading.Thread): 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() - self.join() + 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}) @@ -88,24 +109,44 @@ class PollClient(threading.Thread): def unsubscribe(self, filters): del self.filters[self.filters.index(filters)] -def subscribe(api, filters, on_event, poll_fallback=15): - 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 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") - api = arvados.api(version=api.api_version, cache=False, host=api.api_host, token=api.api_token, insecure=api.api_insecure) - 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) + p.start() + return p