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  • RabbitMQ、Memcached、SQLAlchemy

    一、RabbitMQ

    1、基础概念

    rabbitMQ说白了就是一个消息队列,类似于Queue,也是生产者与消费者模型.只不过做了扩展,所不同的是Queue在内存中的消息队列,而RabbitMQ是部署在机器上的;

    一般而言,生成者往队列中放数据,而消费者从队列中取数据;

    import Queue
    import threading
    message = Queue.Queue(10)
    def producer(i):    #生产者
        while True:
            message.put(i)
    
    def consumer(i):    #消费者
        while True:
            msg = message.get(i)
    
    for i in range(5):
        t=threading.Thread(target=producer,args=(i,))
        t.start()
    for i in range(2):
        t=threading.Thread(target=consumer,args=(i,))
        t.start()
    生产者与消费者模型

    RabbitMQ单独安装在一台服务器上,作为一种消息中间件,生产者和消费者都需要能够连接上这台机器;

    配置安装epel源:      rpm -ivh http://dl.fedoraproject.org/pub/epel/6/i386/epel-release-6-8.noarch.rpm

    安装erlang:           yum -y install erlang

    安装rabbitmq_server并启动服务:    yum -y install rabbitmq-server                  /etc/init.d/rabbitmq-server start

    客户端(生成者和消费者)需要安装API接口pika

    #!/usr/bin/env python
    import pika    
    connection = pika.BlockingConnection(pika.ConnectionParameters(host='192.168.72.80'))
    channel = connection.channel()    #通道
    channel.queue_declare(queue='hello')    #生成队列,名为hello
    channel.basic_publish(exchange='',
                          routing_key='hello',
                          body='Hello World!')     #往队列中插入的数据内容
    print(" [x] Sent 'Hello World!'")
    connection.close()
    producer
    #!/usr/bin/env python
    # _*_ coding:utf-8 _*_
    import pika
    connection = pika.BlockingConnection(pika.ConnectionParameters(
            host='192.168.72.80'))
    channel = connection.channel()
    channel.queue_declare(queue='hello')    #生成一个队列叫做hello,在消费者中可以省略,但前提是生成者首先运行起来,产生消息队列hello,否在在下面往hello队列中取数据的时候,会出错;队列不会重复去定义;
    def callback(ch, method, properties, body):    #body表示拿到的数据
        print(" [x] Received %r" % body)
    channel.basic_consume(callback,    #从hello队列中拿数据,拿到数据就会执行callback函数;no_ack是为了防止消息丢失,如果为False,那么如果消费者没有给生成者返回ack,那么生成者就会将数据再次放入到队列中。
                          queue='hello',
                          no_ack=True)
    print(' [*] Waiting for messages. To exit press CTRL+C')
    channel.start_consuming()
    consumer

    2、RabbitMQ消息失联策略

    关于no_ack=False,如果消费者将队列中的数据取走而没有给应答,那么重新启动消费者的时候依然可以看到之前的数据。

    #!/usr/bin/env python
    # _*_ coding:utf-8 _*_
    import pika
    connection = pika.BlockingConnection(pika.ConnectionParameters(host='192.168.72.80'))
    channel = connection.channel()
    channel.queue_declare(queue='hello')
    def callback(ch, method, properties, body):
        print(" [x] Received %r" % body)
        import time
        time.sleep(10)    
    #拿到数据之后,中断,再次执行看能否接受到数据
        print 'ok'
        ch.basic_ack(delivery_tag = method.delivery_tag)
    channel.basic_consume(callback,
                          queue='hello',
                          no_ack=False)
    print(' [*] Waiting for messages. To exit press CTRL+C')
    channel.start_consuming()
    消费者失联

    3、RabbitMQ服务器异常策略

    如果服务器宕机,列中的数据就会丢失,解决方法是利用持久化,即将数据保存早硬盘中;

    持久化是在生产者部分实现的,要实现持久化,队列和消息必须都要持久化,对于消费者,也可以不指定,取决于先启动生产者还是消费者;

    import pika
    connection = pika.BlockingConnection(pika.ConnectionParameters( host='192.168.72.80'))
    channel = connection.channel()
    # make message persistent
    channel.queue_declare(queue='hello', durable=True)
    
    channel.basic_publish(exchange='',
                          routing_key='hello',
                          body='Hello World!',
                          properties=pika.BasicProperties(
                              delivery_mode=2, # make message persistent
                          ))
    print(" [x] Sent 'Hello World!'")
    connection.close()
    生产者
    import pika
    connection = pika.BlockingConnection(pika.ConnectionParameters(host='192.168.72.80'))
    channel = connection.channel()
    # make message persistent
    channel.queue_declare(queue='hello', durable=True)    #对于之前创建的队列,不能够实现持久化;只能对新创建的队列实现持久化
    def callback(ch, method, properties, body):
        print(" [x] Received %r" % body)
        import time
        time.sleep(10)
        print 'ok'
        ch.basic_ack(delivery_tag = method.delivery_tag)
    channel.basic_consume(callback,
                          queue='hello',
                          no_ack=False)
    print(' [*] Waiting for messages. To exit press CTRL+C')
    channel.start_consuming()
    消费者

    4、RabbitMQ消息获取顺序

    假设有两个消费者,分别往队列中拿数据,一个拿奇数,一个拿偶数,奇数简单而偶数复杂,那么一个消费者永远繁忙,而另一个永远轻松,channel.basic_qos(prefetch_count=1) 表示谁来谁取,不再按照奇偶数排列;

    5、RabbitMQ发布和订阅

    在消息的生成者和消费者中间通过exchange消息中间件实现,发布者在消息发布到队列之前不会将数据发布到队列中,而是放置到exchange中(之前的exchange为空),exchange的名字可以是任意的,exchange可以和多个队列进行绑定,这样exchange会将数据向绑定的队列中各发送一份数据;这样就实现了订阅和发布的功能啦~~~

    以下创建fanout

    import pika
    import sys
    connection = pika.BlockingConnection(pika.ConnectionParameters( host='192.168.72.80'))
    channel = connection.channel()
    channel.exchange_declare(exchange='logs',     #发布者只需绑定exchange
                             type='fanout')
    
    message = ' '.join(sys.argv[1:]) or "info: Hello World!"
    channel.basic_publish(exchange='logs',
                          routing_key='',
                          body=message)
    print(" [x] Sent %r" % message)
    connection.close()
    发布者
    import pika
    connection = pika.BlockingConnection(pika.ConnectionParameters(host='192.168.72.80'))
    channel = connection.channel()
    channel.exchange_declare(exchange='logs',
                             type='fanout')
    result = channel.queue_declare(exclusive=True)
    queue_name = result.method.queue
    channel.queue_bind(exchange='logs',    #消费者需要将队列和exchange绑定起来
                       queue=queue_name)
    print(' [*] Waiting for logs. To exit press CTRL+C')
    def callback(ch, method, properties, body):
        print(" [x] %r" % body)
    channel.basic_consume(callback,
                          queue=queue_name,
                          no_ack=True)
    channel.start_consuming()
    接受者

    6、RabbitMQ实现发布订阅和关键字匹配

    解释fanout类型:exchange收到消息会将数据直接发送给队列

    关键字匹配:根据关键字将exchange的数据发送到不同的队列中;

    #!/usr/bin/env python
    # _*_ coding:utf-8 _*_
    import pika
    import sys
    connection = pika.BlockingConnection(pika.ConnectionParameters(
            host='192.168.72.80'))
    channel = connection.channel()
    channel.exchange_declare(exchange='direct_logs',type='direct')    #必须为direct类型
    message ='Hello World!'
    channel.basic_publish(exchange='direct_logs',
                          routing_key='db',    #生产者发送的关键字
                          body=message)
    print(" [x] Sent %r:%r" % ('dali', message))
    connection.close()
    生产者
    #!/usr/bin/env python
    # _*_ coding:utf-8 _*_
    import pika
    connection = pika.BlockingConnection(pika.ConnectionParameters(host='192.168.72.80'))
    channel = connection.channel()
    channel.exchange_declare(exchange='direct_logs',
                             type='direct')
    result = channel.queue_declare(exclusive=True)
    queue_name = result.method.queue
    channel.queue_bind(exchange='direct_logs',
                       queue=queue_name,
                       routing_key="dali")
    channel.queue_bind(exchange='direct_logs',
                       queue=queue_name,
                       routing_key="db")    #匹配到的关键字
    print(' [*] Waiting for logs. To exit press CTRL+C')
    def callback(ch, method, properties, body):
        print(" [x] %r" % body)
    channel.basic_consume(callback,queue=queue_name,no_ack=True)
    channel.start_consuming()
    消费者1
    #!/usr/bin/env python
    # _*_ coding:utf-8 _*_
    import pika
    connection = pika.BlockingConnection(pika.ConnectionParameters(host='192.168.72.80'))
    channel = connection.channel()
    channel.exchange_declare(exchange='direct_logs',
                             type='direct')
    result = channel.queue_declare(exclusive=True)
    queue_name = result.method.queue
    channel.queue_bind(exchange='direct_logs',
                       queue=queue_name,
                       routing_key="erbi")
    channel.queue_bind(exchange='direct_logs',
                       queue=queue_name,
                       routing_key="db")    #匹配到的关键字
    print(' [*] Waiting for logs. To exit press CTRL+C')
    def callback(ch, method, properties, body):
        print(" [x] %r" % body)
    channel.basic_consume(callback,
                          queue=queue_name,
                          no_ack=True)
    channel.start_consuming()
    消费者2

    关键字模糊匹配:

        #匹配0和或多个单词

        *只能匹配一个单词

    监控作业内容:

    1、使用Redis实现配置信息和数据的传输与存储。
    2、执行命令采集指标
    3、机器分类、实现监控模板
    如:{ 'CPU':{'cmd',}}
    机器根据主机名取模板,key为主机名,value为模板;
    课可以通过反射类实现:
    def cpu():
        return 'CPU指标'
    s='hi'
    func=getattr(api,"hi")
    result = func()
    
    其中api.py最少的监控指标为两项
    4、某个指标超过多长时间内n次报警;
    
    5、使用线程:
    a、每隔几秒,去取自己的模板
    b、使用自己的模板
    
    6、运行程序获取监控指标,通过Redis的订阅和发布功能实现;
    需求

    二、Memcached

    1、基础概念

    将经常访问的内容放在缓存中,Memcache是一种缓存的机制,是管理内存的; Memcached不同于Redis,只有一种数据类型,即key-value;

    安装memcached:

    wget http://memcached.org/latest

    tar -zxvf memcached-1.x.x.tar.gz
    cd memcached-1.x.x
    ./configure && make && make test && sudo make install
    PS:依赖libevent
           yum install libevent-devel
           apt-get install libevent-dev
     
    使用python操作memcached需要安装相关模块:
    https://pypi.python.org/pypi/python-memcached
     
    启动memcached:   memcached -d -m 128 -u root -p 12000
    成功启动之后,可以使用telnet连接memcached操作了.
     
    2、set和set
    import memcache
    mc = memcache.Client(['192.168.72.80:12000'], debug=True)    #debug表示在执行的时候,如果出错,信息就会以debug的模式输出
    mc.set("foo", "bar")  
    ret = mc.get('foo')
    print ret
    set和get

    set还具有修改键值对的功能

    3、Memcached集群

    memcached集群主机中后面会追加权重值,在memcached server内存中会维护一个memcached主机列表,主机列表中主机的重复此处与权重值相关

    假如要执行mc.set("foo", "bar")
    1、将foo转换为一个数字
    import binascii
    print memcache.cmemcache_hash('foo')    #将字符串foo转换为数字
    
    2、将该数字和主机列表长度求余数,将余数作为索引,以此来找到列表中主机的IP,将该KEY_VALUE值存入主机中;
    原理

    4、add

    增加键值对,如果已经存在该键,报错.

    5、replace

    修改某个键的值,如果该键不存在,报错/异常

    6、set和set_multi

    import memcache
    mc = memcache.Client([('192.168.72.80:12000',1)], debug=True)
    mc.set_multi({'key1': 'val1', 'key2': 'val2'})
    print mc.get('key1')
    set_multi

    7、delete和delete_multi

    如果存在该键,删除,不存在,不出异常

    import memcache
    mc = memcache.Client([('192.168.72.80:12000',1)], debug=True)
    mc.set_multi({'key1': 'val1', 'key2': 'val2'})
    print mc.get('key1')
    mc.delete_multi(['key1','key2'])    #键值存在,删除,不存在,报异常
    delete_multi
    8、get和get_multi
    import memcache
    mc = memcache.Client([('192.168.72.80:12000',1)], debug=True)
    mc.set_multi({'key1': 'val1', 'key2': 'val2'})
    print mc.get('key1')
    #mc.delete_multi(['key1','key2'])
    item_dict = mc.get_multi(["key1","key2"])
    print item_dict    #获取结果为字典
    get_multi

    9、append和prepend

    append:指定key的值,在该key后面追加内容

    prepend:指定key的值,在该key的值前面追加内容

    import memcache
    mc = memcache.Client([('192.168.72.80:12000',1)], debug=True)
    mc.set_multi({'k1': 'val1', 'key2': 'val2'})
    print mc.get('k1')
    mc.append('k1','after')    #如果K1的值之前不存在,报异常
    print mc.get('k1')
    mc.prepend('k1','before')
    print mc.get('k1')
    append和prepend

    10、desr和incr

    incr:自增,默认自增1

    decr:自减,默认自减1

    import memcache
    mc = memcache.Client(['192.168.72.80:12000'], debug=True)
    mc.set('k1','777')
    mc.incr('k1')
    print mc.get('k1')
    mc.incr('k1',10)
    mc.decr('k1')
    print mc.get('k1')
    mc.decr('k1',10)
    print mc.get('k1')
    decr和incr

    11、gets和cas

    具体查看

    具体查看memcache.py源代码,本质上是利用socket来send和Recv来实现上述功能的;
     
     
     
    redis文档:http://doc.redisfans.com/
     
     
     
     
    三、SQLALchemy
    参考地址:
              http://www.cnblogs.com/alex3714/articles/5978329.html
     
    sqlarchemy是一款著名的python ORM框架,可以让对数据库小白的用户或者开发者不必写蛋疼的SQL,而直接通过程序语言对数据库进行操作,sqlarchemy提供的程序语言方法,可以先转换为SQL,再通过SQL对数据库进行相关操作;
    可以有四种方式+sqlarchemy进行连接数据库操作,我这里采用的是pymysql,因为windows上安装mysql-python之类的包,会出现各种问题,并且python3目前还不支持mysql-python;
     
    1、创建表;
    sqlarchemy创建数据库表有两种方式:MetaData和declarative_base
     
    使用MetaData
    from sqlalchemy import create_engine,select, Table, Column, Integer, String, MetaData, ForeignKey
    
    metadata = MetaData()
    
    user = Table('user', metadata,
        Column('id', Integer, primary_key=True),
        Column('name', String(20)),
    )
    
    color = Table('color', metadata,
        Column('id', Integer, primary_key=True),
        Column('name', String(20)),
    )
    engine = create_engine("mysql+pymysql://root:@192.168.74.20:3306/test", max_overflow=5)
    
    metadata.create_all(engine)

    declarative_base

    from sqlalchemy import create_engine,and_,or_,func,Table
    from sqlalchemy.ext.declarative import declarative_base
    from sqlalchemy import Column, Integer, String,ForeignKey
    from  sqlalchemy.orm import sessionmaker,relationship
    
    Base = declarative_base() #生成一个SqlORM 基类
    
    
    Host2Group = Table('host_2_group',Base.metadata,
        Column('host_id',ForeignKey('host.id'),primary_key=True),
        Column('group_id',ForeignKey('group.id'),primary_key=True),
    )
    
    
    
    
    engine = create_engine("mysql+pymysql://root:@192.168.74.20:3306/test",echo=True)            #echo=True表示打印出创建过程
    
    
    class Host(Base):
        __tablename__ = 'host'
        id = Column(Integer,primary_key=True,autoincrement=True)
        hostname = Column(String(64),unique=True,nullable=False)
        ip_addr = Column(String(128),unique=True,nullable=False)
        port = Column(Integer,default=22)
        #group_id = Column(Integer, ForeignKey('group.id'))
        groups = relationship('Group',
                              secondary=Host2Group,
                              backref='host_list')
    
        #group =relationship("Group",backref='host_list')
        #group =relationship("Group",back_populates='host_list')
        def __repr__(self):
            return  "<id=%s,hostname=%s, ip_addr=%s>" %(self.id,
                                                        self.hostname,
                                                        self.ip_addr)
    class Group(Base):
        __tablename__ = 'group'
        id = Column(Integer,primary_key=True)
        name = Column(String(64),unique=True,nullable=False)
        #host_id = Column(Integer,ForeignKey('hosts.id'))
        #host_list =relationship("Host", back_populates="group")
        #hosts =relationship("Host")
        def __repr__(self):
            return  "<id=%s,name=%s>" %(self.id,self.name)
    
    Base.metadata.create_all(engine) #创建所有表结构
    

    2、增删改查

    #!/usr/bin/env python
    # -*- coding:utf-8 -*-
    
    from sqlalchemy import create_engine, Table, Column, Integer, String, MetaData, ForeignKey
    
    metadata = MetaData()
    
    user = Table('user', metadata,
        Column('id', Integer, primary_key=True),
        Column('name', String(20)),
    )
    
    color = Table('color', metadata,
        Column('id', Integer, primary_key=True),
        Column('name', String(20)),
    )
    engine = create_engine("mysql+mysqldb://root:123@127.0.0.1:3306/s11", max_overflow=5)
    
    conn = engine.connect()
    
    # 创建SQL语句,INSERT INTO "user" (id, name) VALUES (:id, :name)
    conn.execute(user.insert(),{'id':7,'name':'seven'})
    conn.close()
    
    # sql = user.insert().values(id=123, name='wu')
    # conn.execute(sql)
    # conn.close()
    
    # sql = user.delete().where(user.c.id > 1)
    
    # sql = user.update().values(fullname=user.c.name)
    # sql = user.update().where(user.c.name == 'jack').values(name='ed')
    
    # sql = select([user, ])
    # sql = select([user.c.id, ])
    # sql = select([user.c.name, color.c.name]).where(user.c.id==color.c.id)
    # sql = select([user.c.name]).order_by(user.c.name)
    # sql = select([user]).group_by(user.c.name)
    
    # result = conn.execute(sql)
    # print result.fetchall()
    # conn.close()
    

      

     

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  • 原文地址:https://www.cnblogs.com/cqq-20151202/p/5306338.html
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