Redis学习

Redis是构建高性能、可持久化数据存储的解决方案，他的使用者有Twitter、github、Blizzard、微博等。

 

Redis的优点

1.支持更多的数据类型

2.支持数据持久化

3.内置replication和cluster

4.支持原地更新操作

Memcached的优点

1.多线程

2.更少的内存消耗

3.更少的内存碎片

 

安装

yum install redis -y

查看版本

redis-cli --version
redis-cli 3.2.10

配置文件解析

vim /etc/redis.conf

port 6379 #监听的端口

bind 192.168.1.100 10.0.0.1 #绑定ip，多个ip时空格隔开

databases 16 #指定数据集合数量，默认都存储在0号数据集合

#数据持久化之设置快照
save 900 1
save 300 10
save 60 10000
#   after 900 sec (15 min) if at least 1 key changed
#   after 300 sec (5 min) if at least 10 keys changed
#   after 60 sec if at least 10000 keys changed

启动服务器

service redis start
ss -tnlp

LISTEN      0      128                                                          127.0.0.1:6379                                                                *:*      users:(("redis-server",6527,4))

使用命令行工具连入

redis-cli #默认127.0.0.1
127.0.0.1:6379>

 关闭服务器

redis-cli shutdown

Celery中使用redis

Celery是Python开发的分布式任务调度模块。

 

安装

pip install Celery

编写tasks程序

# -*- coding: utf-8 -*-

import time

from celery import Celery

celery = Celery("tasks",broker="redis://localhost:6379/0")

@celery.task
def sendmail(mail):
	print("sending mail to %s..." % mail['to'])
	time.sleep(3.0)
	print("mail sent.")

 安装redis模块

pip install redis

启动程序

celery -A tasks worker --loglevel=info

User information: uid=0 euid=0 gid=0 egid=0

  uid=uid, euid=euid, gid=gid, egid=egid,
 
 -------------- celery@test v4.1.0 (latentcall)
---- **** ----- 
--- * ***  * -- Linux-2.6.32-642.13.1.el6.x86_64-x86_64-with-centos-6.8-Final 2017-09-08 13:46:11
-- * - **** --- 
- ** ---------- [config]
- ** ---------- .> app:         tasks:0x7f8382775048
- ** ---------- .> transport:   redis://localhost:6379/0
- ** ---------- .> results:     disabled://
- *** --- * --- .> concurrency: 4 (prefork)
-- ******* ---- .> task events: OFF (enable -E to monitor tasks in this worker)
--- ***** ----- 
 -------------- [queues]
                .> celery           exchange=celery(direct) key=celery
                

[tasks]
  . tasks.sendmail

[2017-09-08 13:46:11,582: INFO/MainProcess] Connected to redis://localhost:6379/0
[2017-09-08 13:46:11,592: INFO/MainProcess] mingle: searching for neighbors
[2017-09-08 13:46:12,616: INFO/MainProcess] mingle: all alone
[2017-09-08 13:46:12,629: INFO/MainProcess] celery@test ready.

发送任务

>>> from tasks import sendmail
>>> sendmail.delay(dict(to="xxx@qq.com"))
<AsyncResult: d27a5aca-410e-4b27-b2a6-e3f695ad05c4>

 日志记录

[2017-09-08 13:54:25,638: INFO/MainProcess] Received task: tasks.sendmail[d27a5aca-410e-4b27-b2a6-e3f695ad05c4]  
[2017-09-08 13:54:25,640: WARNING/ForkPoolWorker-1] sending mail to xxx@qq.com...
[2017-09-08 13:54:28,644: WARNING/ForkPoolWorker-1] mail sent.
[2017-09-08 13:54:28,644: INFO/ForkPoolWorker-1] Task tasks.sendmail[d27a5aca-410e-4b27-b2a6-e3f695ad05c4] succeeded in 3.0045828549191356s: None

Celery默认设置就能满足基本要求。Worker以Pool模式启动，默认大小为CPU核心数量，缺省序列化机制是pickle，但可以指定为json。