ZMQ pub sub

client.py

import logging
import random
import time
from threading import Thread

import zmq

logging.basicConfig(encoding="utf-8", level=logging.DEBUG)
logger = logging.getLogger(__name__)

context = zmq.Context()

logger.info("Connecting to broker…")

pub_socket = context.socket(zmq.PUB)
sub_socket = context.socket(zmq.SUB)
pub_socket.connect("tcp://localhost:4000")
sub_socket.connect("tcp://localhost:4001")

logger.info("Connected to broker!")

name = input("Username: ")
topic = input("Topic: ")

sub_socket.setsockopt(zmq.SUBSCRIBE, topic.encode())


def recv():
    while True:
        msg = sub_socket.recv_multipart()
        logger.info("Received msg %s", msg)


def publish():
    while True:
        msg = input("> ")
        time.sleep(random.random())
        logger.info("Sending msg %s", msg)
        pub_socket.send_multipart([topic.encode(), (f"{name}: {msg}").encode()])


recv_thread = Thread(target=recv)
pub_thread = Thread(target=publish)

recv_thread.start()
pub_thread.start()

recv_thread.join()
pub_thread.join()

server.py

import logging

import zmq

logging.basicConfig(encoding="utf-8", level=logging.DEBUG)
logger = logging.getLogger(__name__)

context = zmq.Context()
topic = b"messages"

logger.info("Binding to sockets")

pub_socket = context.socket(zmq.PUB)
sub_socket = context.socket(zmq.SUB)
sub_socket.bind("tcp://*:4000")
pub_socket.bind("tcp://*:4001")
sub_socket.setsockopt(zmq.SUBSCRIBE, topic)

logger.info("Bound sockets!")


# The broker just publishes everything it receives
while True:
    msg = sub_socket.recv_multipart()
    logger.info("Received msg %s", msg)
    pub_socket.send_multipart(msg)

Capturing webcam video and saving to a file

import cv2

vid = cv2.VideoCapture(0)
fourcc = cv2.VideoWriter_fourcc(*"mp4v")
filename = "video.mp4"
fps = 30.0
shape = (640, 480)

writer = cv2.VideoWriter(filename, fourcc, fps, shape)

print("Started capturing")
try:
    # writer.open(filename, fourcc, fps, shape, color)
    while True:
        # Capture a video frame
        ok, frame = vid.read()
        # print(ok, frame)

        writer.write(frame)
except KeyboardInterrupt:
    ...

print("Done")
vid.release()
writer.release()