Python RabbitMQ on Lambda

Python RabbitMQ on Lambda

Checking official documents
https://github.com/benjamin-hodgson/asynqp

More detail in the API document
https://asynqp.readthedocs.io/en/v0.4/reference.html#connecting-to-the-amqp-broker

That is the basic method in python
import asyncio
import asynqp


@asyncio.coroutine
def hello_world():
    """
    Sends a 'hello world' message and then reads it from the queue.
    """
    # connect to the RabbitMQ broker
    connection = yield from asynqp.connect('localhost', 5672, username='guest', password='guest')

    # Open a communications channel
    channel = yield from connection.open_channel()

    # Create a queue and an exchange on the broker
    exchange = yield from channel.declare_exchange('test.exchange', 'direct')
    queue = yield from channel.declare_queue('test.queue')

    # Bind the queue to the exchange, so the queue will get messages published to the exchange
    yield from queue.bind(exchange, 'routing.key')

    # If you pass in a dict it will be automatically converted to JSON
    msg = asynqp.Message({'hello': 'world'})
    exchange.publish(msg, 'routing.key')

    # Synchronously get a message from the queue
    received_message = yield from queue.get()
    print(received_message.json())  # get JSON from incoming messages easily

    # Acknowledge a delivered message
    received_message.ack()

    yield from channel.close()
    yield from connection.close()


if __name__ == "__main__":
    loop = asyncio.get_event_loop()
    loop.run_until_complete(hello_world())

event_loop : endless loop
coroutine: async function, it will be bind to event_loop, event_loop will run that.
task: status of coroutine
future: similar to task
async/await: async coroutine, await block and wait for result

One example to understand:

Import asyncio
Import time

Now = lambda : time.time()

async def do_some_work(x):
    print(‘waiting: ‘, x)

start = now()

coroutine = do_some_work(2)
loop = asyncio.get_event_loop()
task = loop.create_task(coroutine)
print(task)
loop.run_until_complete(task)
print(task)
print(’Time: ‘, now() - start)

Results
<Task pending coro=<do_some_work() running at /
Waiting: 2
<Task finished coro=<do_some_work() done, defined at  result=None>
TIME: 0.0003490447998046875

Very useful details here
https://www.jianshu.com/p/b5e347b3a17c

References:
https://github.com/benjamin-hodgson/asynqp
https://asynqp.readthedocs.io/en/v0.4/

https://docs.aws.amazon.com/lambda/latest/dg/python-context-object.html
https://docs.aws.amazon.com/lambda/latest/dg/nodejs-prog-model-context.html
https://aws.amazon.com/blogs/compute/container-reuse-in-lambda/

https://asynqp.readthedocs.io/en/v0.4/reference.html#connecting-to-the-amqp-broker

https://www.jianshu.com/p/b5e347b3a17c
https://lotabout.me/2017/understand-python-asyncio/