Add week 5 materials

materials/05-indirect-comm/seminar/work_queues/worker/Dockerfile

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+FROM python:3.8
+
+RUN mkdir /root/app/
+WORKDIR /root/app/
+
+RUN pip install pika
+
+COPY . .
+
+ENV PYTHONPATH "${PYTHONPATH}:/root/app/"
+EXPOSE 5000
+
+CMD ["bash", "-c", "while ! curl -s rabbitmq:15672 > /dev/null; do echo waiting for rabbitmq; sleep 3; done; python -u worker.py"]

materials/05-indirect-comm/seminar/work_queues/worker/worker.py

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+#!/usr/bin/env python
+import pika
+import time
+
+
+if __name__ == '__main__':
+    connection = pika.BlockingConnection(pika.ConnectionParameters(host='rabbitmq', port=5672))
+    channel = connection.channel()
+
+    channel.queue_declare(queue='task_queue', durable=True)  # to make sure that the queue will survive a RabbitMQ node restart
+    print(' [*] Waiting for messages.')
+
+
+    def callback(ch, method, properties, body):
+        print(" [x] Received %r" % body.decode())
+        time.sleep(body.count(b'.'))
+        print(" [x] Done")
+        ch.basic_ack(delivery_tag=method.delivery_tag)  # Send ack
+
+
+    channel.basic_qos(prefetch_count=1)  # This uses the basic.qos protocol method to tell RabbitMQ not to give more than one message to a worker at a time
+    channel.basic_consume(queue='task_queue', on_message_callback=callback)
+
+    channel.start_consuming()