| #!/usr/bin/env python |
| # |
| # Licensed to the Apache Software Foundation (ASF) under one |
| # or more contributor license agreements. See the NOTICE file |
| # distributed with this work for additional information |
| # regarding copyright ownership. The ASF licenses this file |
| # to you under the Apache License, Version 2.0 (the |
| # "License"); you may not use this file except in compliance |
| # with the License. You may obtain a copy of the License at |
| # |
| # http://www.apache.org/licenses/LICENSE-2.0 |
| # |
| # Unless required by applicable law or agreed to in writing, |
| # software distributed under the License is distributed on an |
| # "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| # KIND, either express or implied. See the License for the |
| # specific language governing permissions and limitations |
| # under the License. |
| # |
| |
| import sys, getopt, time, logging |
| from kazoo.client import KazooClient |
| from kazoo.exceptions import NodeExistsError |
| from kazoo.retry import KazooRetry |
| |
| logging.getLogger('kazoo.client').addHandler(logging.StreamHandler()) |
| |
| def usage(): |
| sys.stderr.write(''' |
| %s -z <zookeeper> -p <path> [-w|-c|-e] |
| |
| Wait for, or create znode |
| -z Specify zookeeper connect string |
| -p Znode path to watch or create |
| -w Watch for path creation |
| -c Create path |
| -e Check if znode exists |
| ''' % (sys.argv[0])) |
| |
| try: |
| opts, args = getopt.getopt(sys.argv[1:], "z:p:cweh") |
| except getopt.GetoptError as err: |
| sys.stderr.write(str(err) + '\n') |
| usage() |
| sys.exit(2) |
| |
| zookeeper = None |
| znode = None |
| create = False |
| watch = False |
| exists = False |
| |
| for o, a in opts: |
| if o in ("-h"): |
| usage() |
| sys.exit() |
| elif o in ("-z"): |
| zookeeper = a |
| elif o in ("-p"): |
| znode = a |
| elif o in ("-w"): |
| watch = True |
| elif o in ("-c"): |
| create = True |
| elif o in ("-e"): |
| exists = True |
| else: |
| assert False, "unhandled option" |
| usage() |
| sys.exit(2) |
| |
| if not zookeeper: |
| sys.stderr.write("Zookeeper must be specified\n") |
| usage() |
| sys.exit(3) |
| |
| if not znode: |
| sys.stderr.write("Znode must be specified\n") |
| usage() |
| sys.exit(4) |
| |
| if (not watch and not create and not exists): |
| sys.stderr.write("Exactly one of watch (-w), create (-c) or exists (-e) must be specified\n") |
| usage() |
| sys.exit(5) |
| |
| while True: |
| zk = KazooClient(hosts=zookeeper, timeout=1, connection_retry=KazooRetry(max_tries=-1)) |
| try: |
| zk.start() |
| if create: |
| try: |
| zk.create(znode) |
| except NodeExistsError: |
| pass |
| sys.exit(0) |
| elif watch: |
| while not zk.exists(znode): |
| print("Waiting for %s" % znode) |
| time.sleep(1) |
| sys.exit(0) |
| elif exists: |
| if zk.exists(znode): |
| sys.exit(0) |
| else: |
| sys.exit(-1) |
| finally: |
| zk.stop() |
| zk.close() |