为什么zeromq不能在localhost上运行？

Question

此代码的伟大工程：

import zmq, json, time 

def main(): 
    context = zmq.Context() 
    subscriber = context.socket(zmq.SUB) 
    subscriber.bind("ipc://test") 
    subscriber.setsockopt(zmq.SUBSCRIBE, '') 
    while True: 
     print subscriber.recv() 

def main(): 
    context = zmq.Context() 
    publisher = context.socket(zmq.PUB) 
    publisher.connect("ipc://test") 
    while True: 
     publisher.send("hello world") 
     time.sleep(1) 

但这个代码不 *工作：

import zmq, json, time 

def recv(): 
    context = zmq.Context() 
    subscriber = context.socket(zmq.SUB) 
    subscriber.bind("tcp://localhost:5555") 
    subscriber.setsockopt(zmq.SUBSCRIBE, '') 
    while True: 
     print subscriber.recv() 

def send(): 
    context = zmq.Context() 
    publisher = context.socket(zmq.PUB) 
    publisher.connect("tcp://localhost:5555") 
    while True: 
     publisher.send("hello world") 
     time.sleep(1) 

它提出了这样的错误：

ZMQError: No such device

为什么不能zeromq使用localhost接口？

它只在同一台机器上的IPC上工作吗？

Answer 1

的问题是在行：

subscriber.bind("tcp://localhost:5555") 

尝试改变：

subscriber.bind("tcp://127.0.0.1:5555") 

Answer 2

由于@fdb指出：

的问题是在行：

subscriber.bind("tcp://localhost:5555") 

尝试更改为：

subscriber.bind("tcp://127.0.0.1:5555") 

但是这需要更多的解释来理解为什么。

为zmq_bind的文档说明（粗体重点煤矿）：

The endpoint argument is a string consisting of two parts as follows: transport://address . The transport part specifies the underlying transport protocol to use. The meaning of the address part is specific to the underlying transport protocol selected.

由于您的示例使用TCP作为传输协议，我们的zmq_tcp文档中查找发现（再次，大胆重点煤矿）：

When assigning a local address to a socket using zmq_bind() with the tcp transport, the endpoint shall be interpreted as an interface followed by a colon and the TCP port number to use.

An interface may be specified by either of the following:

• The wild-card *, meaning all available interfaces.
• The primary IPv4 address assigned to the interface, in its numeric representation.
• The interface name as defined by the operating system.

因此，如果您不使用通配符或接口名称，那么这意味着您必须使用数字形式的IPv4地址（而不是DNS名称）。

注意，这仅适用于使用zmq_bind！在另一方面，这是完全正常使用，因为在文档中进行zmq_tcp稍后讨论与zmq_connect DNS名称：

When connecting a socket to a peer address using zmq_connect() with the tcp transport, the endpoint shall be interpreted as a peer address followed by a colon and the TCP port number to use.

A peer address may be specified by either of the following:

• The DNS name of the peer.
• The IPv4 address of the peer, in its numeric representation.