A tutorial on how to use the asyncio library in Python
Asyncio is a programming design that achieves concurrency without multi-threading. It is a single-threaded, single-process design. It uses cooperative multitasking, i.e., it gives a sense of concurrency despite using a single thread in a single process.
Coroutines
At the heart of asyncio are coroutines. Coroutines are declared with the async and await syntax. They are in essence awaitable functions.
To run a coroutine, there are three main mechanisms.
1. Use asyncio.run() This executes the passed coroutine, and once finished, closes the threadpool.
async def printHello():
await asyncio.sleep(1) # do something
print('hello')asyncio.run(printHello())
2. Use await on an awaitable object. This is an object that is returned by calling a coroutine function.
Below we execute the coroutines printHello and printGoodbye using the await command.
async def printHello():
await asyncio.sleep(1) # do something
print('hello')async def printGoodbye():
await asyncio.sleep(1) # do something
print('goodbye')
