Coverage for /var/srv/projects/api.amasfac.comuna18.com/tmp/venv/lib/python3.9/site-packages/asgiref/current_thread_executor.py: 24%
43 statements
« prev ^ index » next coverage.py v6.4.4, created at 2023-07-17 14:22 -0600
« prev ^ index » next coverage.py v6.4.4, created at 2023-07-17 14:22 -0600
1import queue
2import threading
3from concurrent.futures import Executor, Future
6class _WorkItem:
7 """
8 Represents an item needing to be run in the executor.
9 Copied from ThreadPoolExecutor (but it's private, so we're not going to rely on importing it)
10 """
12 def __init__(self, future, fn, args, kwargs):
13 self.future = future
14 self.fn = fn
15 self.args = args
16 self.kwargs = kwargs
18 def run(self):
19 if not self.future.set_running_or_notify_cancel():
20 return
21 try:
22 result = self.fn(*self.args, **self.kwargs)
23 except BaseException as exc:
24 self.future.set_exception(exc)
25 # Break a reference cycle with the exception 'exc'
26 self = None
27 else:
28 self.future.set_result(result)
31class CurrentThreadExecutor(Executor):
32 """
33 An Executor that actually runs code in the thread it is instantiated in.
34 Passed to other threads running async code, so they can run sync code in
35 the thread they came from.
36 """
38 def __init__(self):
39 self._work_thread = threading.current_thread()
40 self._work_queue = queue.Queue()
41 self._broken = False
43 def run_until_future(self, future):
44 """
45 Runs the code in the work queue until a result is available from the future.
46 Should be run from the thread the executor is initialised in.
47 """
48 # Check we're in the right thread
49 if threading.current_thread() != self._work_thread:
50 raise RuntimeError(
51 "You cannot run CurrentThreadExecutor from a different thread"
52 )
53 future.add_done_callback(self._work_queue.put)
54 # Keep getting and running work items until we get the future we're waiting for
55 # back via the future's done callback.
56 try:
57 while True:
58 # Get a work item and run it
59 work_item = self._work_queue.get()
60 if work_item is future:
61 return
62 work_item.run()
63 del work_item
64 finally:
65 self._broken = True
67 def submit(self, fn, *args, **kwargs):
68 # Check they're not submitting from the same thread
69 if threading.current_thread() == self._work_thread:
70 raise RuntimeError(
71 "You cannot submit onto CurrentThreadExecutor from its own thread"
72 )
73 # Check they're not too late or the executor errored
74 if self._broken:
75 raise RuntimeError("CurrentThreadExecutor already quit or is broken")
76 # Add to work queue
77 f = Future()
78 work_item = _WorkItem(f, fn, args, kwargs)
79 self._work_queue.put(work_item)
80 # Return the future
81 return f