added rabbitmq helpers and setup command

rmq_helper/__init__.py

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+"""RabbitMQ helpers"""
+from .exchanges import ensure_exchange_exists, exchange_publish
+from .queues import  ensure_queue_exists, queue_publish

rmq_helper/exchanges.py

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+import json
+
+from pika.adapters.blocking_connection import BlockingChannel
+
+from .extension import with_pika_channel
+
+
+@with_pika_channel
+def ensure_exchange_exists(name: str, channel: BlockingChannel = None) -> None:
+    """Ensures exchange exists
+
+    :param name: the name of the exchange
+    :param channel: a pika channel, if none specified a new one will be created
+    """
+    channel.exchange_declare(exchange=name, exchange_type='topic')
+
+
+@with_pika_channel
+def exchange_publish(exchange_name: str, topic: str, message, channel: BlockingChannel = None):
+    """Publishes a message to a
+
+    :param exchange_name: the name of the exchange
+    :param topic: the topic to publish to
+    :param message: the message to publish (will be turned into a json)
+    :param channel: a pika channel, if none specified a new one will be created
+    """
+    ensure_exchange_exists(exchange_name, channel=channel)
+
+    body = json.dumps(message)
+    body_bytes = body.encode('utf-8')
+    channel.basic_publish(exchange=exchange_name, routing_key=topic, body=body_bytes)

rmq_helper/extension.py

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+from functools import wraps
+
+import pika
+
+from .settings import RABBITMQ_HOST
+
+
+def with_pika_channel(f):
+    @wraps(f)
+    def wrapper(*args, **kwargs):
+        # if we are already passing channel, just reuse it
+        if 'channel' in kwargs:
+            return f(*args, **kwargs)
+
+        # otherwise set up a new connection and channel to wrap our code with
+        connection = pika.BlockingConnection(
+            pika.ConnectionParameters(host=RABBITMQ_HOST))
+        channel = connection.channel()
+
+        ret = f(*args, **kwargs, channel=channel)
+
+        channel.close()
+        return ret
+
+    return wrapper

rmq_helper/queues.py

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+import json
+
+from pika.adapters.blocking_connection import BlockingChannel
+
+from .extension import with_pika_channel
+
+
+@with_pika_channel
+def ensure_queue_exists(name: str, channel: BlockingChannel = None):
+    channel.queue_declare(queue=name)
+
+
+@with_pika_channel
+def queue_publish(queue_name: str, message, channel: BlockingChannel = None):
+    ensure_queue_exists(queue_name, channel=channel)
+
+    body = json.dumps(message)
+    body_bytes = body.encode('utf-8')
+    channel.basic_publish(exchange='', routing_key=queue_name, body=body_bytes)

rmq_helper/settings.py

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+import os
+
+RABBITMQ_HOST = os.environ.get("RABBITMQ_HOST", "localhost")