provide a fix for asyncio on Windows + Python pre-3.8

.github/workflows/tests.yml

@@ -15,11 +15,16 @@ jobs:
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        python-version: [3.6, 3.7, 3.8]
+        python-version: [3.6, 3.7, 3.8, 3.9]
         os:
           - ubuntu-latest
           - macos-latest
           - windows-latest
+        exclude:
+          - os: windows-latest
+            python-version: 3.9
+          - os: macos-latest
+            python-version: 3.9
       fail-fast: false
 
     steps:

examples/blender/blender.py

@@ -3,7 +3,13 @@
 import pathlib
 import sys
 
-from yapapi import Executor, Task, __version__ as yapapi_version, WorkContext
+from yapapi import (
+    Executor,
+    Task,
+    __version__ as yapapi_version,
+    WorkContext,
+    windows_event_loop_fix,
+)
 from yapapi.log import enable_default_logger, log_summary, log_event_repr  # noqa
 from yapapi.package import vm
 from datetime import timedelta
@@ -86,19 +92,21 @@ async def worker(ctx: WorkContext, tasks):
     args = parser.parse_args()
 
     # This is only required when running on Windows with Python prior to 3.8:
-    utils.windows_event_loop_fix()
+    windows_event_loop_fix()
 
     enable_default_logger(log_file=args.log_file)
+
     loop = asyncio.get_event_loop()
+
     subnet = args.subnet_tag
     sys.stderr.write(
         f"yapapi version: {utils.TEXT_COLOR_YELLOW}{yapapi_version}{utils.TEXT_COLOR_DEFAULT}\n"
     )
     sys.stderr.write(f"Using subnet: {utils.TEXT_COLOR_YELLOW}{subnet}{utils.TEXT_COLOR_DEFAULT}\n")
     task = loop.create_task(main(subnet_tag=args.subnet_tag))
     try:
-        asyncio.get_event_loop().run_until_complete(task)
+        loop.run_until_complete(task)
     except (Exception, KeyboardInterrupt) as e:
         print(e)
         task.cancel()
-        asyncio.get_event_loop().run_until_complete(task)
+        loop.run_until_complete(task)

examples/utils.py

@@ -23,15 +23,3 @@ def build_parser(description: str):
         "--log-file", default=None, help="Log file for YAPAPI; default: %(default)s"
     )
     return parser
-
-
-def windows_event_loop_fix():
-    """Set up asyncio to use ProactorEventLoop implementation for new event loops on Windows."""
-
-    # For Python 3.8 ProactorEventLoop is already the default on Windows
-    if sys.platform == "win32" and sys.version_info < (3, 8):
-
-        class _WindowsEventPolicy(asyncio.events.BaseDefaultEventLoopPolicy):
-            _loop_factory = asyncio.windows_events.ProactorEventLoop
-
-        asyncio.set_event_loop_policy(_WindowsEventPolicy())

examples/yacat/yacat.py

@@ -4,7 +4,7 @@
 import pathlib
 import sys
 
-from yapapi import Executor, Task, WorkContext
+from yapapi import Executor, Task, WorkContext, windows_event_loop_fix
 from yapapi.log import enable_default_logger, log_summary, log_event_repr  # noqa
 from yapapi.package import vm
 
@@ -142,7 +142,7 @@ async def worker_find_password(ctx: WorkContext, tasks):
     args = parser.parse_args()
 
     # This is only required when running on Windows with Python prior to 3.8:
-    utils.windows_event_loop_fix()
+    windows_event_loop_fix()
 
     enable_default_logger(log_file=args.log_file)
 

tests/test_yapapi.py

@@ -1,3 +1,4 @@
+import asyncio
 import toml
 from pathlib import Path
 
@@ -9,3 +10,14 @@ def test_version():
         pyproject = toml.loads(f.read())
 
     assert yapapi.__version__ == pyproject["tool"]["poetry"]["version"]
+
+
+def test_windows_event_loop_fix():
+    async def _asyncio_test():
+        await asyncio.create_subprocess_shell("")
+
+    yapapi.windows_event_loop_fix()
+
+    l = asyncio.get_event_loop()
+    t = l.create_task(_asyncio_test())
+    l.run_until_complete(t)

yapapi/__init__.py

@@ -1,4 +1,6 @@
 """Golem Python API."""
+import asyncio
+import sys
 import toml
 
 from pathlib import Path
@@ -21,6 +23,22 @@ def get_version() -> str:
     return get_distribution("yapapi").version
 
 
+def windows_event_loop_fix():
+    """
+    Set up asyncio to use ProactorEventLoop implementation for new event loops on Windows.
+
+    This work-around is only needed for Python 3.6 and 3.7.
+    With Python 3.8, `ProactorEventLoop` is already the default on Windows.
+    """
+
+    if sys.platform == "win32" and sys.version_info < (3, 8):
+
+        class _WindowsEventPolicy(asyncio.events.BaseDefaultEventLoopPolicy):
+            _loop_factory = asyncio.windows_events.ProactorEventLoop
+
+        asyncio.set_event_loop_policy(_WindowsEventPolicy())
+
+
 __version__: str = get_version()
 __all__ = [
     "Executor",