python分布式rpc框架zerorpc安装及使用教程

矫情吗；* 2022-06-15 06:17 1205阅读 0赞

#### 1.简介及安装 ####

rpc使构建分布式系统简单许多，在云计算的实现中有很广泛的应用  
rpc可以是异步的

python实现rpc，可以使用标准库里的SimpleXMLRPCServer，另外zerorpc是第三方库支持rpc  
zerorpc 是基于 ZeroMQ 和 MessagePack，速度相对快，响应时间短，并发高

zerorpc需要额外安装，而SimpleXMLRPCServer不需要额外安装，但是SimpleXMLRPCServer性能相对差一些

zerorpc安装：

yum -y install gcc\*  
yum -y install gcc-c++ libuuid-devel python-uuid uuid  
yum -y install zlib zlib-dev

安装pip：  
wget [https://bootstrap.pypa.io/get-pip.py][https_bootstrap.pypa.io_get-pip.py]  
python get-pip.py

pip安装：  
pip install zerorpc

zerorpc实际上会依赖msgpack-python, pyzmq, future, greenlet, gevent

其中gevent支持协程

Installing collected packages: msgpack-python, pyzmq, future, greenlet, gevent, zerorpc
      Running setup.py install for msgpack-python ... done
      Running setup.py install for future ... done
      Running setup.py install for zerorpc ... done
    Successfully installed future-0.16.0 gevent-1.2.1 greenlet-0.4.12 msgpack-python-0.4.8 pyzmq-16.0.2 zerorpc-0.6.1

官网参考：[http://www.zerorpc.io/][http_www.zerorpc.io]

#### 2.使用示例： ####

说明：此实验在centos6版本中运行成功的，  
但是在centos7中调试一直有异常，表现为,zerorpc请求超时zerorpc.exceptions.LostRemote: Lost remote after 10s heartbeat  
这个错误也可能会出现在请求没有对应的响应函数时，zerorpc不会抛出异常，等待超时

Traceback (most recent call last):
      File "<stdin>", line 1, in <module>
      File "/usr/local/python27/lib/python2.7/site-packages/zerorpc/core.py", line 278, in <lambda>
        return lambda *args, **kargs: self(method, *args, **kargs)
      File "/usr/local/python27/lib/python2.7/site-packages/zerorpc/core.py", line 270, in __call__
        return self._process_response(request_event, bufchan, timeout)
      File "/usr/local/python27/lib/python2.7/site-packages/zerorpc/core.py", line 227, in _process_response
        reply_event = bufchan.recv(timeout=timeout)
      File "/usr/local/python27/lib/python2.7/site-packages/zerorpc/channel.py", line 255, in recv
        event = self._input_queue.get(timeout=timeout)
      File "/usr/local/python27/lib/python2.7/site-packages/gevent/queue.py", line 284, in get
        return self.__get_or_peek(self._get, block, timeout)
      File "/usr/local/python27/lib/python2.7/site-packages/gevent/queue.py", line 261, in __get_or_peek
        result = waiter.get()
      File "/usr/local/python27/lib/python2.7/site-packages/gevent/hub.py", line 899, in get
        return self.hub.switch()
      File "/usr/local/python27/lib/python2.7/site-packages/gevent/hub.py", line 630, in switch
        return RawGreenlet.switch(self)
    zerorpc.exceptions.LostRemote: Lost remote after 10s heartbeat

1.基本应用

服务端：

import zerorpc
    
    class HelloRPC(object):
        def hello(self, name):
            return "Hello, %s" % name
    
    s = zerorpc.Server(HelloRPC())
    s.bind("tcp://0.0.0.0:4242")
    s.run()

客户端：

import zerorpc
    
    c = zerorpc.Client()
    c.connect("tcp://127.0.0.1:4242")
    print c.hello("RPC")

结果：

>>> c.connect("tcp://127.0.0.1:4242")
    [None]
    >>> print c.hello("RPC")
    Hello, RPC
    >>>

注：  
服务端的s = zerorpc.Server(HelloRPC())，服务注册，只注册一个类，若注册注册多个，则运行时一般不会有异常，但客服端发送调用请求，执行时可能会抛出异常  
例如：

服务端：
    
    import zerorpc
    
    class HelloRPC(object):
        def hello(self, name):
            return "Hello, %s" % name
    class resRPC(object):
        def x(self, name):
            return "Hello, %s" % name
    
    s = zerorpc.Server(HelloRPC(),resRPC())
    #或注册两个
    #s = zerorpc.Server(resRPC())
    #s = zerorpc.Server(HelloRPC())
    s.bind("tcp://0.0.0.0:4242")
    s.run()
    
    客户端：
    import zerorpc
    
    c = zerorpc.Client()
    c.connect("tcp://127.0.0.1:4242")
    print c.hello("RPC")
    print c.x("RPC")

当执行print c.x(“RPC”)会抛出类似如下异常： raise NameError(event.name)

2.流式响应

import zerorpc
    
    class StreamingRPC(object):
        @zerorpc.stream
        def streaming_range(self, fr, to, step):
            return xrange(fr, to, step)
    
    s = zerorpc.Server(StreamingRPC())
    s.bind("tcp://0.0.0.0:4242")
    s.run()

客户端：

import zerorpc
    
    c = zerorpc.Client()
    c.connect("tcp://127.0.0.1:4242")
    
    for item in c.streaming_range(10, 20, 2):
        print item

结果：

>>> c.connect("tcp://127.0.0.1:4242")
    [None]
    >>> 
    >>> for item in c.streaming_range(10, 20, 2):
    ...    print item
    ... 
    10
    12
    14
    16
    18
    >>>

注：  
@zerorpc.stream这里的函数修饰是必须的，否则会有异常，如TypeError: can’t serialize

import zerorpc
    
    class StreamingRPC(object):
        def streaming_range(self, fr, to, step):
            return xrange(fr, to, step)
    
    s = zerorpc.Server(StreamingRPC())
    s.bind("tcp://0.0.0.0:4242")
    s.run()

异常信息：

raise exception
    zerorpc.exceptions.RemoteError: Traceback (most recent call last):
      File "/usr/local/python27/lib/python2.7/site-packages/zerorpc/core.py", line 153, in _async_task
        functor.pattern.process_call(self._context, bufchan, event, functor)
      File "/usr/local/python27/lib/python2.7/site-packages/zerorpc/patterns.py", line 34, in process_call
        channel.emit_event(rep_event)
      File "/usr/local/python27/lib/python2.7/site-packages/zerorpc/channel.py", line 234, in emit_event
        self._channel.emit_event(event)
      File "/usr/local/python27/lib/python2.7/site-packages/zerorpc/heartbeat.py", line 116, in emit_event
        self._channel.emit_event(event, timeout)
      File "/usr/local/python27/lib/python2.7/site-packages/zerorpc/channel.py", line 154, in emit_event
        self._multiplexer.emit_event(event, timeout)
      File "/usr/local/python27/lib/python2.7/site-packages/zerorpc/channel.py", line 66, in emit_event
        return self._events.emit_event(event, timeout)
      File "/usr/local/python27/lib/python2.7/site-packages/zerorpc/events.py", line 347, in emit_event
        parts.extend([b'', event.pack()])
      File "/usr/local/python27/lib/python2.7/site-packages/zerorpc/events.py", line 208, in pack
        r = msgpack.Packer(use_bin_type=True).pack(payload)
      File "msgpack/_packer.pyx", line 231, in msgpack._packer.Packer.pack (msgpack/_packer.cpp:3661)
      File "msgpack/_packer.pyx", line 233, in msgpack._packer.Packer.pack (msgpack/_packer.cpp:3503)
      File "msgpack/_packer.pyx", line 221, in msgpack._packer.Packer._pack (msgpack/_packer.cpp:3230)
      File "msgpack/_packer.pyx", line 221, in msgpack._packer.Packer._pack (msgpack/_packer.cpp:3230)
      File "msgpack/_packer.pyx", line 228, in msgpack._packer.Packer._pack (msgpack/_packer.cpp:3382)
    TypeError: can't serialize xrange(10, 20, 2)

3.传入多个参数

服务端：

import zerorpc
    
    class myRPC(object):
        def listinfo(self,message):
            return "get info : %s"%message
    
        def getpow(self,n,m):
            return n**m           
    
    s = zerorpc.Server(myRPC())
    s.bind("tcp://0.0.0.0:4242")
    s.run()

客户端：

import zerorpc
    
    c = zerorpc.Client()
    c.connect("tcp://127.0.0.1:4242")
    print c.listinfo("this is test string")
    print c.getpow(2,5)

注：函数定义中,都需要定义一个默认self，否则将抛出TypeError异常：  
TypeError: getpow() takes exactly 2 arguments (3 given)  
例如：  
将getpow改为如下：

def getpow(n,m):
            return n**m

异常信息：

4.获取时间  
服务端

import zerorpc
    import datetime
    
    class GetMessage(object):
        def showget(self, str):
            return "get message : %s" %str
        def showtime(self):        
             now = datetime.datetime.now()
             return now.strftime('%Y-%m-%d %H:%M:%S')  
    
    s = zerorpc.Server(GetMessage())
    s.bind("tcp://0.0.0.0:8081")
    s.run()

客服端：

import zerorpc
    
    myclient = zerorpc.Client()
    myclient.connect("tcp://192.168.137.19:8081")
    print myclient.showget("RPC")
    print myclient.showtime()

5.返回文件内容

服务端：

import zerorpc
    
    class readfile(object):
        def readone(self,filepath):
            try:
              f = open(filepath)
              line = f.readline()
              return "%s file list one : %s" %(filepath,line)
            except:
              return "could not open filepath,file may not exists."  
    
        def readall(self,filepath):        
            try:
              f = open(filepath)
              lines = f.readlines()
              strfile=[]
              for line in lines:
                  strfile.append(line)
              return "%s file list one : %s" %(filepath,strfile)
            except:
              return "could not open filepath,file may not exists."  
    
    s = zerorpc.Server(readfile())
    s.bind("tcp://0.0.0.0:8081")
    s.run()

客户端：

import zerorpc
    
    myclient = zerorpc.Client()
    myclient.connect("tcp://192.168.137.19:8081")
    print myclient.readone("ip.txt")
    print myclient.readall()

结果：

>>> print myclient.readone("ip.txt")
    ip.txt file list one : 192.168.1.1
    
    >>> print myclient.readall("ip.txt")
    ip.txt file list one : ['192.168.1.1\n', '192.168.1.2\n', '192.168.1.3\n', '192.168.1.4\n', '192.168.1.5\n', '192.168.1.6\n']
    >>>

另：  
对于可变参数\*\*kwargs，传入暂时无法成功获取结果，故暂不建议使用可变参数

这个可能是由于zerorpc内部的实现中定义多可变参数，所以无法传入传入用户定义  
比如：self.\_functor(\*args, \*\*kargs)  
例：

server:
    import zerorpc
    
    class myRPC(object):
        def func(self,**kwargs):
           mes=[]
           for key in kwargs:
               ks="%s: %s"%(key, kwargs[key])
               mes.append(ks)
    
           return mes     
    
    s = zerorpc.Server(myRPC())
    s.bind("tcp://0.0.0.0:4242")
    s.run()
    
    
    
    client:
    import zerorpc
    
    c = zerorpc.Client()
    c.connect("tcp://127.0.0.1:4242")
    print c.func(a="abc")

返回不到想要的结果：

>>> c.connect("tcp://127.0.0.1:4242")
    [None] 
    >>> print c.func(a="abc")
    []

[https_bootstrap.pypa.io_get-pip.py]: https://bootstrap.pypa.io/get-pip.py
[http_www.zerorpc.io]: http://www.zerorpc.io/