Add exponential backoff to connection attempts.

Delay will approximately double between attempts (random variation).

See issue #67.
This commit is contained in:
Lance Stout 2011-05-27 14:42:40 -07:00
parent 384e1a92b7
commit b81ab97900

View file

@ -17,6 +17,7 @@ import sys
import threading
import time
import types
import random
try:
import queue
except ImportError:
@ -45,6 +46,9 @@ HANDLER_THREADS = 1
# Flag indicating if the SSL library is available for use.
SSL_SUPPORT = True
# Maximum time to delay between connection attempts is one hour.
RECONNECT_MAX_DELAY = 3600
log = logging.getLogger(__name__)
@ -104,7 +108,11 @@ class XMLStream(object):
use_ssl -- Flag indicating if SSL should be used.
use_tls -- Flag indicating if TLS should be used.
stop -- threading Event used to stop all threads.
auto_reconnect -- Flag to determine whether we auto reconnect.
reconnect_max_delay -- Maximum time to delay between connection
attempts. Defaults to RECONNECT_MAX_DELAY,
which is one hour.
Methods:
add_event_handler -- Add a handler for a custom event.
@ -155,6 +163,7 @@ class XMLStream(object):
self.ca_certs = None
self.response_timeout = RESPONSE_TIMEOUT
self.reconnect_max_delay = RECONNECT_MAX_DELAY
self.state = StateMachine(('disconnected', 'connected'))
self.state._set_state('disconnected')
@ -291,9 +300,14 @@ class XMLStream(object):
# is established.
connected = self.state.transition('disconnected', 'connected',
func=self._connect)
delay = 1.0
while reattempt and not connected:
connected = self.state.transition('disconnected', 'connected',
func=self._connect)
delay = min(delay * 2, self.reconnect_max_delay)
delay = random.normalvariate(delay, delay * 0.1)
log.debug('Waiting %s seconds before reconnecting.' % delay)
time.sleep(delay)
return connected
def _connect(self):