Last modified: Feb 02, 2025 By Alexander Williams
Python pyzmq.Poller() Guide: Efficient Socket Polling
In ZeroMQ applications, managing multiple sockets efficiently is crucial. The pyzmq.Poller()
class helps you monitor sockets for events like incoming messages. This guide explains how to use it effectively.
What is pyzmq.Poller()?
The pyzmq.Poller()
class is part of the PyZMQ library. It allows you to monitor multiple sockets for events such as readability, writability, or errors. This is especially useful in asynchronous or event-driven applications.
Why Use pyzmq.Poller()?
Using pyzmq.Poller()
ensures your application can handle multiple sockets without blocking. It improves performance by allowing you to respond to events as they occur, rather than polling sockets manually.
How to Use pyzmq.Poller()
To use pyzmq.Poller()
, you first create an instance of the class. Then, you register sockets with the poller and specify the events you want to monitor. Finally, you call the poll()
method to wait for events.
Example: Basic Usage
Below is an example of how to use pyzmq.Poller()
to monitor two sockets for incoming messages.
import zmq
# Create a context and sockets
context = zmq.Context()
socket1 = context.socket(zmq.PULL)
socket2 = context.socket(zmq.PULL)
# Bind sockets to endpoints
socket1.bind("tcp://*:5555")
socket2.bind("tcp://*:5556")
# Create a poller and register sockets
poller = zmq.Poller()
poller.register(socket1, zmq.POLLIN)
poller.register(socket2, zmq.POLLIN)
# Poll for events
while True:
socks = dict(poller.poll())
if socket1 in socks:
message = socket1.recv_string()
print(f"Received from socket1: {message}")
if socket2 in socks:
message = socket2.recv_string()
print(f"Received from socket2: {message}")
In this example, the poller monitors both sockets for incoming messages. When a message arrives, it prints the message to the console.
Output Example
Received from socket1: Hello from socket1
Received from socket2: Hello from socket2
Advanced Usage
You can also use pyzmq.Poller()
to monitor sockets for different events. For example, you can monitor a socket for both readability and writability.
Example: Monitoring Multiple Events
Here’s how you can monitor a socket for both incoming messages and the ability to send messages.
import zmq
# Create a context and socket
context = zmq.Context()
socket = context.socket(zmq.REP)
# Bind socket to an endpoint
socket.bind("tcp://*:5555")
# Create a poller and register socket
poller = zmq.Poller()
poller.register(socket, zmq.POLLIN | zmq.POLLOUT)
# Poll for events
while True:
socks = dict(poller.poll())
if socket in socks and socks[socket] == zmq.POLLIN:
message = socket.recv_string()
print(f"Received: {message}")
if socket in socks and socks[socket] == zmq.POLLOUT:
socket.send_string("Reply")
In this example, the poller monitors the socket for both incoming and outgoing events. When a message is received, it prints the message. When the socket is ready to send, it sends a reply.
Conclusion
The pyzmq.Poller()
class is a powerful tool for managing multiple sockets in ZeroMQ applications. It allows you to monitor sockets for events efficiently, improving the performance of your application. By following the examples in this guide, you can start using pyzmq.Poller()
in your projects today.
For more advanced socket handling, consider exploring other PyZMQ features or related libraries like Python httpx.stream_ws() for WebSocket streaming.