Skip to content

Instantly share code, notes, and snippets.

@tonyseek
Last active July 4, 2019 17:16
Show Gist options
  • Star 0 You must be signed in to star a gist
  • Fork 0 You must be signed in to fork a gist
  • Save tonyseek/f9e5cd98f99676b79b956c4b184d71e4 to your computer and use it in GitHub Desktop.
Save tonyseek/f9e5cd98f99676b79b956c4b184d71e4 to your computer and use it in GitHub Desktop.
Use TreeCache of Kazoo to get node data.
import logging
import threading
from kazoo.client import KazooClient
from kazoo.recipe.cache import TreeCache, TreeEvent
class TreeCacheListener(object):
CONNECTIVE_EVENTS = {
TreeEvent.CONNECTION_SUSPENDED: 'SUSPENDED',
TreeEvent.CONNECTION_RECONNECTED: 'RECONNECTED',
TreeEvent.CONNECTION_LOST: 'LOST',
}
def __init__(self, tree_cache):
self._log = logging.getLogger('{0}.{1}'.format(
__name__, self.__class__.__name__))
self._cache = tree_cache
self._initialized = threading.Event()
def start(self, timeout=5):
self._cache.listen(self._handle_event)
self._cache.listen_fault(self._handle_fault)
self._cache.start()
return self._initialized.wait(timeout)
def _handle_event(self, event):
if not self._initialized.is_set():
if event.event_type == TreeEvent.INITIALIZED:
self._initialized.set()
return
if event.event_type in self.CONNECTIVE_EVENTS:
event_name = self.CONNECTIVE_EVENTS[event.event_type]
self._log.info('Connective event %s happened', event_name)
return
if event.event_type in (
TreeEvent.NODE_ADDED,
TreeEvent.NODE_UPDATED,
TreeEvent.NODE_REMOVED):
# NOTE We are able to do something on the tree cache now
return
def _handle_fault(self, error):
self._log.exception(error)
def example():
client = KazooClient()
client.start()
tree_cache = TreeCache(client, '/kazoo-treecache-example')
tree_listener = TreeCacheListener(tree_cache)
tree_listener.start() # block until the tree cache is initialized
path, data, stat = tree_cache.get_data('/kazoo-treecache-example')
print('\n=> {0} = {1!r}; {2}'.format(path, data, stat))
if __name__ == '__main__':
logging.basicConfig(level=logging.DEBUG)
example()
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment