1. 缘起

实现Zookeeper集群监控任务时候，需要用4字命令探测Zookeeper运行状态。

2. 分析

如果只需要执行Zookeeper四字命令，不需要ZkClient，简单的Socket链接即可。

3. 基本思路

• 建立Socket链接；

• 发送四字命令；

• 接收返回信息；

• 解析返回信息。

4. 代码

import socket
 
 
"""
    by liuhailong2008#foxmail.com
"""
 
 
def multi_line_with_split(data, split_char):
    lines = data.split('\n')
    ret = {}
    for line in lines:
        if len(line) == 0:
            continue
        item = line.split(split_char)
        if len(item) > 1:
            ret[item[0]] = item[1]
    return ret
 
 
def multi_line_with_equal_split(data):
    return multi_line_with_split(data, '=')
 
 
def multi_line_with_tab_split(data):
    return multi_line_with_split(data, '\t')
 
 
def multi_line_with_colon_split(data):
    return multi_line_with_split(data, ':')
 
 
def single_line(data):
    return {'result':data}
 
 
response_parser_repository = {
    'conf': multi_line_with_equal_split,
    'envi': multi_line_with_equal_split,
    'mntr': multi_line_with_tab_split,
    'srvr': multi_line_with_colon_split,
    'ruok': single_line,
 
}
 
 
def get_response_parser(four_word_command):
    return response_parser_repository.get(four_word_command, None)
 
 
def talk_to_zookeeper(four_word_command, host='127.0.0.1', port=2181,  timeout=1):
    conn = socket.socket()
    conn.settimeout(timeout)
    conn.connect((host,port))
    conn.send(four_word_command)
    response_data = conn.recv(2048)
    conn.close()
    # print response_data
    parser = get_response_parser(four_word_command)
    if parser is None:
        return response_data
    return parser(response_data)
 
 
if __name__ == '__main__':
    print 'ruok: %s ' % talk_to_zookeeper('ruok')
    print 'conf: %s ' % talk_to_zookeeper('conf')
    print 'envi: %s ' % talk_to_zookeeper('envi')
    print 'srvr: %s ' % talk_to_zookeeper('srvr')
    print 'mntr: %s ' % talk_to_zookeeper('mntr')

程序执行输出：

ruok: {'result': 'imok'} 
conf: {'clientPort': '2181', 'minSessionTimeout': '4000', 'maxClientCnxns': '60', 'dataLogDir': '/Users/liuhailong/work/zookeeper-3.4.9/bin/./data/version-2', 'dataDir': '/Users/liuhailong/work/zookeeper-3.4.9/bin/./data/version-2', 'maxSessionTimeout': '40000', 'serverId': '0', 'tickTime': '2000'} 
envi: {'java.io.tmpdir': '/var/folders/dz/x623731n505999d3gky1jyg00000gn/T/', 'java.class.path': '/Users/liuhailong/work/zookeeper-3.4.9/bin/../build/classes:/Users/liuhailong/work/zookeeper-3.4.9/bin/../build/lib/*.jar:/Users/liuhailong/work/zookeeper-3.4.9/bin/../lib/slf4j-log4j12-1.6.1.jar:/Users/liuhailong/work/zookeeper-3.4.9/bin/../lib/slf4j-api-1.6.1.jar:/Users/liuhailong/work/zookeeper-3.4.9/bin/../lib/netty-3.10.5.Final.jar:/Users/liuhailong/work/zookeeper-3.4.9/bin/../lib/log4j-1.2.16.jar:/Users/liuhailong/work/zookeeper-3.4.9/bin/../lib/jline-0.9.94.jar:/Users/liuhailong/work/zookeeper-3.4.9/bin/../zookeeper-3.4.9.jar:/Users/liuhailong/work/zookeeper-3.4.9/bin/../src/java/lib/*.jar:/Users/liuhailong/work/zookeeper-3.4.9/bin/../conf:', 'java.library.path': '/Users/liuhailong/Library/Java/Extensions:/Library/Java/Extensions:/Network/Library/Java/Extensions:/System/Library/Java/Extensions:/usr/lib/java:.', 'java.compiler': '<NA>', 'os.version': '10.14.4', 'os.arch': 'x86_64', 'zookeeper.version': '3.4.9-1757313, built on 08/23/2016 06:50 GMT', 'java.home': '/Library/Java/JavaVirtualMachines/jdk1.8.0_171.jdk/Contents/Home/jre', 'user.dir': '/Users/liuhailong/work/zookeeper-3.4.9/bin', 'java.version': '1.8.0_171', 'os.name': 'Mac OS X', 'java.vendor': 'Oracle Corporation', 'host.name': '192.168.1.5', 'user.home': '/Users/liuhailong', 'user.name': 'liuhailong'} 
srvr: {'Received': ' 104', 'Node count': ' 4', 'Outstanding': ' 0', 'Zxid': ' 0x6', 'Zookeeper version': ' 3.4.9-1757313, built on 08/23/2016 06', 'Connections': ' 1', 'Latency min/avg/max': ' 0/1/8', 'Mode': ' standalone', 'Sent': ' 103'} 
mntr: {'zk_outstanding_requests': '0', 'zk_approximate_data_size': '27', 'zk_max_latency': '8', 'zk_avg_latency': '1', 'zk_version': '3.4.9-1757313, built on 08/23/2016 06:50 GMT', 'zk_watch_count': '0', 'zk_num_alive_connections': '1', 'zk_open_file_descriptor_count': '31', 'zk_server_state': 'standalone', 'zk_packets_sent': '104', 'zk_packets_received': '105', 'zk_min_latency': '0', 'zk_ephemerals_count': '0', 'zk_znode_count': '4', 'zk_max_file_descriptor_count': '10240'}