Global async Redis connection in Tornado web demo

app.py

import asyncio_redis
import tornado.locks
import tornado.web

from tornado.options import define, options

define("port", default=8888, help="run on the given port", type=int)


class AsyncRedisConnectionContextManager:
    def __init__(self, *args, **kwargs):
        self.args = args
        self.kwargs = kwargs

    async def __aenter__(self):
        self.rdb = await asyncio_redis.Connection.create(*self.args,
                                                         **self.kwargs)
        return self.rdb

    async def __aexit__(self, exc_type, exc, tb):
        self.rdb.close()


class Application(tornado.web.Application):
    def __init__(self, rdb):
        self.rdb = rdb
        handlers = [
            (r"/", MainHandler),
        ]
        settings = {
            'debug': True,
        }
        super(Application, self).__init__(handlers, **settings)


class MainHandler(tornado.web.RequestHandler):

    async def get(self):
        print('get you!')
        connection = self.application.rdb
        # subscriber = await connection.start_subscribe()
        # await subscriber.subscribe(['chan1'])
        print(id(connection))

        keys = await connection.keys('*')
        print(f'keys: {keys}')

        # _ = await connection.set('hello', 'world')
        # world = await connection.get('hello')
        # print(f'hello: {world}')

        cnt = await connection.incr('cnt')
        self.write("Hello, World, {}".format(cnt))

        # try:
        #     hit = await connection.brpop(["zzz"], timeout=60)
        # except asyncio_redis.TimeoutError as _:
        #     hit = None

        # # hit = await subscriber.next_published()
        # self.write("Hello, World, {}".format(hit))


async def main():
    tornado.options.parse_command_line()

    # Create the global connection.
    async with AsyncRedisConnectionContextManager('127.0.0.1', 6379) as rdb:
        app = Application(rdb)
        app.listen(options.port)

        # In this demo the server will simply run until interrupted
        # with Ctrl-C, but if you want to shut down more gracefully,
        # call shutdown_event.set().
        shutdown_event = tornado.locks.Event()
        await shutdown_event.wait()


if __name__ == "__main__":
    tornado.ioloop.IOLoop.current().run_sync(main)

panfei.py

# By panfei via CPyUG 2018-08-15

import tornado.web
import asyncio_redis


class MainHandler(tornado.web.RequestHandler):
    @classmethod
    async def redis_connection(cls):
        if not hasattr(cls, '_redis_connection'):
            cls._redis_connection = await asyncio_redis.Connection.create('127.0.0.1', 6379)
        return cls._redis_connection

    async def get(self):
        print('get you!')
        connection: asyncio_redis.Connection = await MainHandler.redis_connection()
        # subscriber = await connection.start_subscribe()
        # await subscriber.subscribe(['chan1'])
        print(id(connection))
        try:
            hit = await connection.brpop(["zzz"], timeout=60)
        except asyncio_redis.TimeoutError as _:
            hit = None
        finally:
            connection.close()
        # hit = await subscriber.next_published()
        self.write("Hello, World, {}".format(hit))

Pipfile

[[source]]
url = "https://pypi.org/simple"
verify_ssl = true
name = "pypi"

[packages]
tornado = "==5.1"
asyncio-redis = "==0.15.1"

[dev-packages]

[requires]
python_version = "3.7"

Pipfile.lock

{
    "_meta": {
        "hash": {
            "sha256": "b5211f547712f2a34691344cea49441d55cf6139db38d661331ba62f181d5488"
        },
        "pipfile-spec": 6,
        "requires": {
            "python_version": "3.7"
        },
        "sources": [
            {
                "name": "pypi",
                "url": "https://pypi.org/simple",
                "verify_ssl": true
            }
        ]
    },
    "default": {
        "asyncio-redis": {
            "hashes": [
                "sha256:067dbc251ab84d6e53ef8b33dbfd8afd62987ab08f72ca922f6870c96be53b54",
                "sha256:f49e2c6626f3fcfddb478ee1d01f0335e22b6656add274e8a88fcdec9bd78745"
            ],
            "index": "pypi",
            "version": "==0.15.1"
        },
        "tornado": {
            "hashes": [
                "sha256:1c0816fc32b7d31b98781bd8ebc7a9726d7dce67407dc353a2e66e697e138448",
                "sha256:4f66a2172cb947387193ca4c2c3e19131f1c70fa8be470ddbbd9317fd0801582",
                "sha256:5327ba1a6c694e0149e7d9126426b3704b1d9d520852a3e4aa9fc8fe989e4046",
                "sha256:6a7e8657618268bb007646b9eae7661d0b57f13efc94faa33cd2588eae5912c9",
                "sha256:a9b14804783a1d77c0bd6c66f7a9b1196cbddfbdf8bceb64683c5ae60bd1ec6f",
                "sha256:c58757e37c4a3172949c99099d4d5106e4d7b63aa0617f9bb24bfbff712c7866",
                "sha256:d8984742ce86c0855cccecd5c6f54a9f7532c983947cff06f3a0e2115b47f85c"
            ],
            "index": "pypi",
            "version": "==5.1"
        }
    },
    "develop": {}
}