timeout param is not respected

[rahav]

Expected Behavior

1. The default timeout is respected.
2. If specified, the timeout is respected.

Actual Behavior

The computers on which the 3 ZK servers run are deliberately OFF. Run the client from a forth computer.

In the client code, define 3 hosts in the KazooClient() statement. The start() statement that follows, cycles through the hosts in about 5 seconds per host. Not 10 as expected.

Setting the timeout in the call to KazooClient() or start() does not change this duration.

Snippet to Reproduce the Problem

zk = KazooClient(hosts='rpi17.local:2181,rpi18.local:2181,rpi19.local:2181')   # Adding timeout param does not change behavior
zk.start()`   # or zk.start(timeout=15)

Logs with logging in DEBUG mode

Cannot resolve rpi17.local: [Errno 8] nodename nor servname provided, or not known
Cannot resolve rpi18.local: [Errno 8] nodename nor servname provided, or not known
Cannot resolve rpi19.local: [Errno 8] nodename nor servname provided, or not known
Failed connecting to Zookeeper within the connection retry policy.
Traceback (most recent call last):
File "/Users/Dropbox/Idempotent/ZooKeeper/zkMyCli.py", line 441, in
zk.start(timeout=15)
File "/Users/rahav/anaconda3/lib/python3.11/site-packages/kazoo/client.py", line 669, in start
raise self.handler.timeout_exception("Connection time-out")
kazoo.handlers.threading.KazooTimeoutError: Connection time-out

Specifications

• Kazoo version: 2.10.0
• Result of pip list command: kazoo 2.10.0
• Zookeeper version: 3.8.4
• Zookeeper configuration:
• Python version: 3.11.5
• OS: macOS

[StephenSorriaux]

Hello,

Thank you for the issue.

In the example and logs you've given, I don't think there is any way to get the "10s per host timeout" you would expect with Kazoo as the error you are getting is a DNS error that prevents Kazoo for making a connection since, well, your hostnames cannot be resolved to a valid IP address. Most of the time there is a 5s timeout for resolving a hostname so that's why you are noticing that specific value. You could probably update your system DNS settings to achieve what you want (maybe some options timeout:10 would work).

With Kazoo, you could make use of some KazooRetry() to retry more, for instance:

from kazoo.client import KazooClient
from kazoo.retry import KazooRetry

zk = KazooClient(hosts='rpi17.local:2181,rpi18.local:2181,rpi19.local:2181', connection_retry=KazooRetry(max_tries=-1)) # infinite retries
zk.start(timeout=30) # wait for 30s... or more depending on the number of hosts + DNS setting