Python - asyncio

• only one task runs at a time
• other tasks proceed when first function is asleep, waiting or done

Just using sleep, not really asynchronous:

import asyncio

async def fn():
    print('This is ')
    await asyncio.sleep(1)
    print('asynchronous programming')
    await asyncio.sleep(1)
    print('and not multi-threading')

asyncio.run(fn())

just using sleep, not really asynchronous:

import asyncio

async def fn():

    print("one")
    await asyncio.sleep(1)
    await fn2()
    print('four')
    await asyncio.sleep(1)
    print('five')
    await asyncio.sleep(1)

async def fn2():
    await asyncio.sleep(1)
    print("two")
    await asyncio.sleep(1)
    print("three")
asyncio.run(fn())

task is run once there is time ( while main is sleeping ):

import asyncio
async def fn():
    task=asyncio.create_task(fn2())
    print("one")
    #await asyncio.sleep(1)
    #await fn2()
    print('four')
    await asyncio.sleep(1)
    print('five')
    await asyncio.sleep(1)

async def fn2():
    #await asyncio.sleep(1)
    print("two")
    await asyncio.sleep(1)
    print("three")

asyncio.run(fn())

Parallel tasks ( could be used for IO ):

import asyncio


async def func1():
    print("Function 1 started..")
    await asyncio.sleep(2)             # sleep OR do IO instead
    print("Function 1 Ended")


async def func2():
    print("Function 2 started..")
    await asyncio.sleep(3)
    print("Function 2 Ended")


async def func3():
    print("Function 3 started..")
    await asyncio.sleep(1)
    print("Function 3 Ended")


async def main():
    L = await asyncio.gather(
        func1(),
        func2(),
        func3(),
    )
    print("Main Ended..")


asyncio.run(main())