Coverage for /pythoncovmergedfiles/medio/medio/usr/local/lib/python3.8/asyncio/runners.py: 19%

1__all__ = 'run', 

2 

3from . import coroutines 

4from . import events 

5from . import tasks 

6 

7 

8def run(main, *, debug=False): 

9 """Execute the coroutine and return the result. 

10 

11 This function runs the passed coroutine, taking care of 

12 managing the asyncio event loop and finalizing asynchronous 

13 generators. 

14 

15 This function cannot be called when another asyncio event loop is 

16 running in the same thread. 

17 

18 If debug is True, the event loop will be run in debug mode. 

19 

20 This function always creates a new event loop and closes it at the end. 

21 It should be used as a main entry point for asyncio programs, and should 

22 ideally only be called once. 

23 

24 Example: 

25 

26 async def main(): 

27 await asyncio.sleep(1) 

28 print('hello') 

29 

30 asyncio.run(main()) 

31 """ 

32 if events._get_running_loop() is not None: 

33 raise RuntimeError( 

34 "asyncio.run() cannot be called from a running event loop") 

35 

36 if not coroutines.iscoroutine(main): 

37 raise ValueError("a coroutine was expected, got {!r}".format(main)) 

38 

39 loop = events.new_event_loop() 

40 try: 

41 events.set_event_loop(loop) 

42 loop.set_debug(debug) 

43 return loop.run_until_complete(main) 

44 finally: 

45 try: 

46 _cancel_all_tasks(loop) 

47 loop.run_until_complete(loop.shutdown_asyncgens()) 

48 finally: 

49 events.set_event_loop(None) 

50 loop.close() 

51 

52 

53def _cancel_all_tasks(loop): 

54 to_cancel = tasks.all_tasks(loop) 

55 if not to_cancel: 

56 return 

57 

58 for task in to_cancel: 

59 task.cancel() 

60 

61 loop.run_until_complete( 

62 tasks.gather(*to_cancel, loop=loop, return_exceptions=True)) 

63 

64 for task in to_cancel: 

65 if task.cancelled(): 

66 continue 

67 if task.exception() is not None: 

68 loop.call_exception_handler({ 

69 'message': 'unhandled exception during asyncio.run() shutdown', 

70 'exception': task.exception(), 

71 'task': task, 

72 })