Imagine that you're coding a Discord bot and every time somebody uses a command, you need to get some information from a database. But there's a catch: the database servers are acting up today and take a whole 10 seconds to respond. If you do not use asynchronous methods, your whole bot will stop running until it gets a response from the database. How do you fix this? Asynchronous programming.
What is asynchronous programming?
An asynchronous program utilises the async and await keywords. An asynchronous program pauses what it's doing and does something else whilst it waits for some third-party service to complete whatever it's supposed to do. Any code within an async context manager or function marked with the await keyword indicates to Python, that whilst this operation is being completed, it can do something else. For example:
import discord
# Bunch of bot code
async def ping(ctx):
await ctx.send("Pong!")awaiting it. This tells Python that this step must be completed before it can do anything else. Common examples of blocking operations, as simple as they may seem, include: outputting text, adding two numbers and appending an item onto a list. Most common Python libraries have an asynchronous version available to use in asynchronous contexts.
async libraries
- The standard async library - asyncio
- Asynchronous web requests - aiohttp
- Talking to PostgreSQL asynchronously - asyncpg
- MongoDB interactions asynchronously - motor
- Check out this list for even more!