RabbitMQ之tutorial-4

发表于 2020-12-11 更新于 2020-12-29 分类于 RabbitMQ

RabbitMQ之tutorial-4

Tutorial four

ttps://www.rabbitmq.com/tutorials/tutorial-four-python.html

Compared with fanout mindless broadcast, Receiving messages selectively

Direct exchange

a message goes to the queues whose binding key exactly matches the routing key of the message

It is perfectly legal to bind multiple queues with the same binding key

Diect Exchange 和queue做binding的时候

支持一个queue 多个binding key
支持多个queue 同一个binding key

Sender

import pika
import sys


connection = pika.BlockingConnection(
    pika.ConnectionParameters(host='localhost'))
channel = connection.channel()

channel.exchange_declare(exchange='direct_logs', exchange_type='direct')


severity = sys.argv[1] if len(sys.argv) > 2 else 'info'
message = ' '.join(sys.argv[2:]) or 'Hello World!'

channel.basic_publish(
    exchange='direct_logs',
    routing_key=severity,
    body=message
)
print(" [x] Sent %r:%r" % (severity, message))

connection.close()

Receiver

import pika
import sys


connection = pika.BlockingConnection(
    pika.ConnectionParameters(host='localhost'))
channel = connection.channel()

channel.exchange_declare(exchange='direct_logs', exchange_type='direct')


result = channel.queue_declare(queue='', exclusive=True)
queue_name = result.method.queue

severities = sys.argv[1:]
if not severities:
    sys.stderr.write("Usage: %s [info] [warning] [error]\n" % sys.argv[0])
    sys.exit(1)

for sev in severities:
    channel.queue_bind(
        exchange='direct_logs', queue=queue_name, routing_key=sev)
print(' [*] Waiting for logs. To exit press CTRL+C')


def callback(ch, method, properties, body):
    print(" [x] %r:%r" % (method.routing_key, body))


channel.basic_consume(
    queue=queue_name, on_message_callback=callback, auto_ack=True)

channel.start_consuming()

Testing

// receiver 指定binding key
python receive_logs_direct.py warning error 

python receive_logs_direct.py info warning error


// sender 指指定routingkey 和 msg
python emit_log_direct.py error "Run. Run. Or it will explode."

python emit_log_direct.py info "normal event 1"

python emit_log_direct.py warning "some warning"