rampante 0.0.2

🐎 Rampante

A fancy and opinionated nanoframework for microservices.

Installation

pip install rampante

How to use subscribe_on

from rampante import subscribe_on

# The function should accept 3 params
# queue_name, for example could be "user.subscribed"
# data is a dictionary, it's a msgpacked message sent to Kafka
# producer is an instance of AIOKafkaProducer, if you want to send new events

@subscribe_on("user.subscribed")
async def send_a_message(queue_name, data, producer):
    log.info("Event received!")

@subscribe_on("user.subscribed", "user.created")
async def send_another_message(queue_name, data, producer):
    log.info("Event received!")

Example

import asyncio
import logging

import msgpack
from aiokafka import AIOKafkaProducer
from rampante import scheduler, subscribe_on

log = logging.getLogger()
handler = logging.StreamHandler()
formatter = logging.Formatter(
    '[%(asctime)s %(name)s %(levelname)s] %(message)s')
handler.setFormatter(formatter)
log.addHandler(handler)
log.setLevel(logging.INFO)

KAFKA_URI = 'localhost:9092'

@subscribe_on("user.subscribed")
async def send_a_message(queue_name, data, producer):
    log.info("Event received!")

async def stop_task_manager(app):
    """Cancel task manager."""
    if 'task_manager' in app:
        app['task_manager'].cancel()
        await app['task_manager']

if __name__ == '__main__':
    loop = asyncio.get_event_loop()
    try:
        loop.run_until_complete(scheduler(kafka_uri=KAFKA_URI, loop=loop, queue_size=10))
    except KeyboardInterrupt:
        log.warning("Shutting down!")

Example with aiohttp

import asyncio
import logging

import msgpack
from aiohttp import web
from aiokafka import AIOKafkaProducer
from rampante import scheduler, subscribe_on

log = logging.getLogger()
handler = logging.StreamHandler()
formatter = logging.Formatter(
    '[%(asctime)s %(name)s %(levelname)s] %(message)s')
handler.setFormatter(formatter)
log.addHandler(handler)
log.setLevel(logging.INFO)

KAFKA_URI = 'localhost:9092'


@subscribe_on("user.subscribed")
async def send_a_message(queue_name, data, producer):
    log.info("Event received!")


async def handle(request):
    name = request.match_info.get('name', "Anonymous")
    text = "Hello, " + name
    body = msgpack.packb({"message": "Hello", "priority": 3})
    await request.app['events_queue'].send_and_wait("user.subscribed", body)
    return web.Response(text=text)


async def start_event_connection(app):
    """Connect to Kafka."""
    connection = AIOKafkaProducer(loop=app.loop, bootstrap_servers=KAFKA_URI)
    await connection.start()
    app['events_queue'] = connection


async def stop_event_connection(app):
    """Close connection with Kafka."""
    if 'events_queue' in app:
        await app['events_queue'].stop()


async def start_task_manager(app):
    """Load task manager."""
    app['task_manager'] = asyncio.ensure_future(
        scheduler(kafka_uri=KAFKA_URI, loop=app.loop, queue_size=10))


async def stop_task_manager(app):
    """Cancel task manager."""
    if 'task_manager' in app:
        app['task_manager'].cancel()
        await app['task_manager']

if __name__ == '__main__':
    app = web.Application()
    app.router.add_get('/{name}', handle)
    # On-startup tasks
    app.on_startup.append(start_event_connection)
    app.on_startup.append(start_task_manager)
    # Clean-up tasks
    app.on_cleanup.append(stop_task_manager)
    app.on_cleanup.append(stop_event_connection)
    web.run_app(app)

The name

Rampante means “rampant” in Italian.

Why Kafka?

I like aiokafka, but I plan to switch to Redis as soon as Stream will be officially available.

To Do

• add circuit breaker

• add retry

• add logic when tasks fail

• add consumer position

Pull requests are encouraged!

License

Apache 2.0