安装
pip install redis
示例代码
# import redis
from redis.sentinel import Sentinel
"""
1、通过访问Sentinel服务的方式，获取redis的master、slave节点信息
2、向master redis写入数据
3、从slave redis读取数据
"""
# 连接哨兵服务器(主机名也可以用域名)
sentinel = Sentinel([('192.168.196.129', 26379),
('192.168.196.132', 26379)
],
socket_timeout=0.5)
# 获取主服务器地址
master = sentinel.discover_master('mymaster')
print(master)
# 输出：('192.168.196.132', 6379)
# 获取从服务器地址
slave = sentinel.discover_slaves('mymaster')
print(slave)
# 输出：[('192.168.196.129', 6379)]
# 获取主服务器进行写入
master = sentinel.master_for('mymaster', socket_timeout=0.5, password='newpwd', db=0)
w_ret = master.set('foo', 'bar')
# 输出：True
# 获取从服务器进行读取（默认是round-roubin,随机从多个slave服务中读取数据）
slave = sentinel.slave_for('mymaster', socket_timeout=0.5, password='newpwd', db=0)
r_ret = slave.get('foo')
print(r_ret)
# 输出：bar
封装工具类方法
from redis.sentinel import Sentinel
class redisSentinelHelper():
def __init__(self,sentinel_list,service_name,password,db):
self.sentinel = Sentinel(sentinel_list,socket_timeout=0.5)
self.service_name = service_name
self.password = password
self.db = db
def get_master_redis(self):
return self.sentinel.discover_master(self.service_name)
def get_slave_redis(self):
return self.sentinel.discover_slaves(self.service_name)
def set_key(self,key,value):
master = self.sentinel.master_for(
service_name=self.service_name,
socket_timeout=0.5,
password=self.password,
db=self.db
)
return master.set(key,value)
def get_key(self,key):
slave = self.sentinel.slave_for(
service_name=self.service_name,
socket_timeout=0.5,
password=self.password,
db=self.db
)
return slave.get(key)
def _test():
# redis info
sentinel_list = [('192.168.196.129', 26379),('192.168.196.132', 26379)]
password = 'newpwd'
db = 0
service_name = 'mymaster'
# create redis link
rsh = redisSentinelHelper(sentinel_list=sentinel_list,password=password,service_name=service_name,db=db)
# test set key : key1 test-insert-key1
rsh.set_key('key1','test-insert-key1')
# get key1
print(rsh.get_key('key1'))
if __name__ == '__main__':
_test()
运行如下：
D:\Python37\python3.exe D:/pythonProject/redis-test/test7.py
b'test-insert-key1'
其中，我没有把设置master节点写在初始化，而是在set key操作的时候才创建连接，主要是后续想要测试master节点变化的情况下，写入能够继续。
当然这样的话性能肯定不会很好，有很多可以根据实际情况修改的地方。
测试：当master节点切换，能否自动连续写入
当然，在sentinel执行master切点切换的过程，肯定会有些丢失，但是主要是要看切换之后，是否可以自动继续写入数据。
首先编写一个循环写入的示例
from redis.sentinel import Sentinel
class redisSentinelHelper():
def __init__(self,sentinel_list,service_name,password,db):
self.sentinel = Sentinel(sentinel_list,socket_timeout=0.5)
self.service_name = service_name
self.password = password
self.db = db
def get_master_redis(self):
return self.sentinel.discover_master(self.service_name)
def get_slave_redis(self):
return self.sentinel.discover_slaves(self.service_name)
def set_key(self,key,value):
master = self.sentinel.master_for(
service_name=self.service_name,
socket_timeout=0.5,
password=self.password,
db=self.db
)
return master.set(key,value)
def get_key(self,key):
slave = self.sentinel.slave_for(
service_name=self.service_name,
socket_timeout=0.5,
password=self.password,
db=self.db
)
return slave.get(key)
def _test():
# redis info
sentinel_list = [('192.168.196.129', 26379),('192.168.196.132', 26379)]
password = 'newpwd'
db = 0
service_name = 'mymaster'
# create redis link
rsh = redisSentinelHelper(sentinel_list=sentinel_list,password=password,service_name=service_name,db=db)
# test set key : key1 test-insert-key1
# rsh.set_key('key1','test-insert-key1')
# get key1
# print(rsh.get_key('key1'))
# loop set key
for i in range(0,1000000):
rsh.set_key('key' + str(i), i)
print(rsh.get_key('key' + str(i)))
if __name__ == '__main__':
_test()
运行如下：
在写入的过程停止master服务
脚本由于socket连接异常，直接报终止了。
查看sentinel的日志如下：
1825:X 17 Apr 17:44:51.101 # +sdown master mymaster 192.168.196.132 6379
1825:X 17 Apr 17:44:51.194 # +new-epoch 3
1825:X 17 Apr 17:44:51.195 # +vote-for-leader 3607cde178c7ac4255d5f862e8f3892f5599100f 3
1825:X 17 Apr 17:44:52.230 # +odown master mymaster 192.168.196.132 6379 #quorum 2/2
1825:X 17 Apr 17:44:52.230 # Next failover delay: I will not start a failover before Wed Apr 17 17:50:52 2019
1825:X 17 Apr 17:44:52.274 # +config-update-from sentinel 3607cde178c7ac4255d5f862e8f3892f5599100f 192.168.196.129 26379 @ mymaster 192.168.196.132 6379
1825:X 17 Apr 17:44:52.274 # +switch-master mymaster 192.168.196.132 6379 192.168.196.129 6379
1825:X 17 Apr 17:44:52.274 * +slave slave 192.168.196.131:6379 192.168.196.131 6379 @ mymaster 192.168.196.129 6379
1825:X 17 Apr 17:44:52.274 * +slave slave 192.168.196.132:6379 192.168.196.132 6379 @ mymaster 192.168.196.129 6379
1825:X 17 Apr 17:45:22.298 # +sdown slave 192.168.196.132:6379 192.168.196.132 6379 @ mymaster 192.168.196.129 6379
1825:X 17 Apr 17:45:22.298 # +sdown slave 192.168.196.131:6379 192.168.196.131 6379 @ mymaster 192.168.196.129 6379
[root@centos7-server02 redis]#
可以看到已经切换了master节点，这时候抛开刚才的异常问题，再执行一下脚本看看。
在master节点切换之后，再次运行脚本
直接就可以访问处理了。
这里就体现了通过sentinel集群来获取master节点的优势。
