NATS subscriber

consumer.py

import asyncio
import json
import ssl
import sys
from nats.aio.client import Client as NATS

async def error_cb(e):
    print("Error:", e)
    
async def run(loop):
    # Connection to NATS
    nc = NATS()

    # Use server's CA
    ssl_ctx = ssl.create_default_context(purpose=ssl.Purpose.SERVER_AUTH)
    ssl_ctx.load_verify_locations('./certs/ca.pem')
    
    options = {
        "servers": ["nats://messaging.techwhale.io:4222"],
        "io_loop": loop,
        "tls": ssl_ctx,
        "error_cb": error_cb
    }
    await nc.connect(**options)
    print("Connected to NATS: {}".format(nc.connected_url.netloc))

    # Handling incoming messages
    async def message_handler(msg):
        data = json.loads(msg.data.decode())
        print(data)
  
    # Subscription to all messages published to the provided subject (if authorized to)
    subject = "nats.demo"
    await nc.subscribe(subject, cb=message_handler)
        print('Subscribed to [%s]' % subject);

if __name__ == '__main__':
    loop = asyncio.get_event_loop()
    loop.run_until_complete(run(loop))
    try:
        loop.run_forever()
    finally:
        loop.close()