Asyncio

• Designed for “cooperative/non-preemptive multitasking”
• Implements “parallelism” with only 1 thread
• asnyc declares a “coroutine” (asynchronous function)
• Coroutines can be paused at some point to wait for an event without blocking other tasks in the same program
  • Use the await keyword in the function body to wait
    • At every await, the interpreter can switch to a different coroutine (if others are pending)
    • At every await, the compiler splits the function into 2 parts (before and after)
• Example: start a second task

  task2 = asyncio.ensure_future(task2_fun())

  • Starts task2_fun() as a parallel task (and returns a handle)
  • We need to await it before the end of main such that the program doesn’t stop too early

    await sec_task