etcd leader election in python

leader_election.py

from os import urandom
from etcd import Client, EtcdKeyNotFound
from time import sleep
from uuid import uuid4

# Usually, read this from the local node's configuration
me = uuid4().hex
client = Client()


def find_the_leader(service, ttl=10):
    service = str(service)
    try:
        client.test_and_set(service + '/leader', me, me, ttl=ttl)
        print('I am still the leader')
    except EtcdKeyNotFound:
        client.write(service + '/leader', me, ttl=ttl, prevExist=False)
        print('I am the leader')
    except ValueError as ve:
        leader = ve.message.split()[-1][:-1]
        print('The leader is: {}'.format(leader))


def main():
    while True:
        find_the_leader('/service')
        # simulate flaky conditions
        sleep(ord(urandom(1)) % 15)

if __name__ == '__main__':
    try:
        main()
    except KeyboardInterrupt:
        try:
            client.delete('/service/leader', prevValue=me)
        except ValueError:
            # I wasn't the leader anyway
            pass