python redis中lpop()方法是获取并删除左边第一个对象。
python
def lpop(
self,
name: str,
count: Optional[int] = None,
) -> Union[Awaitable[Union[str, List, None]], Union[str, List, None]]:
"""
Removes and returns the first elements of the list ``name``.
By default, the command pops a single element from the beginning of
the list. When provided with the optional ``count`` argument, the reply
will consist of up to count elements, depending on the list's length.
For more information see https://redis.io/commands/lpop
"""
python redis中blpop()方法是获取并删除左边第一个对象,并多了一个阻塞的作用(如果传入的timeout参数大于零,执行blpop()是会检查集合里面有没有对象,没有对象则进行阻塞timeout秒,如果timeout为0或者不传则无期限代码阻塞,直到有新的对象加入到集合)。
python
def blpop(
self, keys: List, timeout: Optional[int] = 0
) -> Union[Awaitable[list], list]:
"""
LPOP a value off of the first non-empty list
named in the ``keys`` list.
If none of the lists in ``keys`` has a value to LPOP, then block
for ``timeout`` seconds, or until a value gets pushed on to one
of the lists.
If timeout is 0, then block indefinitely.
For more information see https://redis.io/commands/blpop
"""
测试lpop()方法:
python
import redis
import time
if __name__ == "__main__":
# 使用连接池来管理多个连接
pool = redis.ConnectionPool(host='127.0.0.1', port=6379,password="123456", db=0)
redis_client = redis.StrictRedis(connection_pool=pool)
while True:
#获取消息队列
print("读取mq队列")
task = redis_client.lpop("task")
if task is not None:
print("收到消息: " + str(task))
#执行任务
time.sleep(1)
结果每秒会获取一次:
测试blpop()方法:
python
import redis
import time
if __name__ == "__main__":
# 使用连接池来管理多个连接
pool = redis.ConnectionPool(host='127.0.0.1', port=6379,password="123456", db=0)
redis_client = redis.StrictRedis(connection_pool=pool)
while True:
#获取消息队列
print("读取mq队列")
task = redis_client.blpop(_task")
if task is not None:
print("收到消息: " + str(task))
#执行任务
time.sleep(1)
结果只读取一次,然后就阻塞了:
直到有对象进入集合,才会继续执行代码。
python
import redis
if __name__ == "__main__":
# 使用连接池来管理多个连接
pool = redis.ConnectionPool(host='127.0.0.1', port=6379,password="123456", db=0)
redis_client = redis.StrictRedis(connection_pool=pool)
# 设置键值对
redis_client.rpush("task","22")