johnliu55tw / asyncio_in_10_minutes

Understanding asyncio in 10 minutes.

Python asyncio in 10 minutes

asyncio in 10 minutes is the talk I gave in SITCON 2018 @ KKBOX booth. This repository contains some useful information about the talk.

Example code

KKBOX Open API Token

Noted that you need to have a token for accessing KKBOX Open API to run the example code. If you don't know what this is, check out the article Beginner's guide for Python developers.

Nevertheless, if you don't want to read the whold article, follow these steps to retrive the token:

1. Go to My Apps, register and create an app. You should see a page that has ID and Secret.
2. use the get_token.py, provides your ID and Secret as the command-line arguments to fetch the token. For example if your ID is ffc7bfde578dcf76185d6695da165512 and Secret is 99c08eff076587acee496a01c5d8a66e:

$ python3 get_token.py ffc7bfde578dcf76185d6695da165512 99c08eff076587acee496a01c5d8a66e

3. There should be a base64 encoded string printed on the screen. That is your token.

$ python3 get_token.py ffc7bfde578dcf76185d6695da165512 99c08eff076587acee496a01c5d8a66e
tGm6Nizi6zRd/kmBhgCXwg==  <- This is your token

pipenv

The example code requires two modules: requests and aiohttp. Pipfiles are provided to create a development environment with pipenv:

$ cd asyncio_in_10_minutes
$ pipenv install --three

Running the code

The directory examples contains two example codes: fetch_sync.py and fetch_asyncio.py, which demonstrate fetching several tracks from KKBOX Open API in synchronous and asynchronous manner respectively.

Before you run the example code, remember to set up the TOKEN variable with your own token:

...

TOKEN = 'Replace this string with your token'

...

For example, if your token is tGm6Nizi6zRd/kmBhgCXwg==, the code should be like:

...

TOKEN = 'tGm6Nizi6zRd/kmBhgCXwg=='

...

There are three files that contains different number of track IDs: 20_tracks, 40_tracks and 60_tracks. You should change the TRACK_FILE variable to one of the three track IDs files listed here and see the result.

Caveat

If you have used asyncio before, or you have inspected the result carefully, you should have noticed that their is a difference between fetch_sync.py and fetch_asyncio.py: The order of resulting tracks information compare to the input file.

I encourage you to see why is this happening and find out a solution after you have read this chapter from the official document of asyncio (Hint: as_completed() vs. gather()).

Slides

• Link to the slide.