Add asyncio.run() and asyncio.run_in_executor() functions.

python · 1st1 · Nov 10, 2016 · Nov 15, 2016 · Nov 15, 2016 · Nov 15, 2016
commit db2fe1d1e1d0f7352167a2ff00c4296115810adc
diff --git a/asyncio/__init__.py b/asyncio/__init__.py
@@ -24,6 +24,7 @@
 from .futures import *
 from .locks import *
 from .protocols import *
+from .run import *
 from .queues import *
 from .streams import *
 from .subprocess import *

diff --git a/asyncio/base_events.py b/asyncio/base_events.py
@@ -38,7 +38,7 @@
 from .log import logger
 
 
-__all__ = ['BaseEventLoop']
+__all__ = ['BaseEventLoop', 'run_in_executor']
 
 
 # Minimum number of _scheduled timer handles before cleanup of
@@ -55,6 +55,27 @@
                        ConnectionResetError, ConnectionAbortedError)
 
 
+@coroutine
+def run_in_executor(executor, func, *args):
+    """Run the function in a thread or a process pool.
+
+    Any concurrent.futures executor can be passed to the
+    function.
+
+    If executor is None, the function will be run in
+    the default threadpool of the event loop.
+
+    Example:
+
+        async def coro():
+            await asyncio.run_in_executor(
+                None, long_calculation, 42)
+    """
+    loop = events.get_event_loop()
+    result = yield from loop.run_in_executor(executor, func, *args)
+    return result
+
+
 def _format_handle(handle):
     cb = handle._callback
     if inspect.ismethod(cb) and isinstance(cb.__self__, tasks.Task):

diff --git a/asyncio/run.py b/asyncio/run.py
@@ -0,0 +1,68 @@
+"""asyncio.run() function."""
+
+__all__ = ['run']
+
+import threading
+
+from . import coroutines
+from . import events
+
+
+def run(coro, *, debug=False):
+    """Run a coroutine.
+
+    This function runs the passed coroutine,
AE04
 taking care of
+    managing the asyncio event loop and finalizing asynchronous
+    generators.
+
+    This function must be called from the main thread, and it
+    cannot be called when another asyncio event loop is running.
+
+    If debug is True, the event loop will be run in debug mode.
+
+    This function should be used as a main entry point for
+    asyncio programs, and should not be used to call asynchronous
+    APIs.
+
+    Example::
+
+        import asyncio
+
+        async def main():
+            await asyncio.sleep(1)
+            print('hello')
+
+        asyncio.run(main())
+    """
+    if events._get_running_loop() is not None:
+        raise RuntimeError(
+            "asyncio.run() cannot be called from a running event loop")
+    if not isinstance(threading.current_thread(), threading._MainThread):
+        raise RuntimeError(
+            "asyncio.run() must be called from the main thread")
+    if not coroutines.iscoroutine(coro):
+        raise ValueError("a coroutine was expected, got {!r}".format(coro))
+
+    loop = events.new_event_loop()
+    try:
+        events.set_event_loop(loop)
+
+        if debug:
+            loop.set_debug(True)
+
+        result = loop.run_until_complete(coro)
+
+        try:
+            # `shutdown_asyncgens` was added in Python 3.6; not all
+            # event loops might support it.
+            shutdown_asyncgens = loop.shutdown_asyncgens
+        except AttributeError:
+            pass
+        else:
+            loop.run_until_complete(shutdown_asyncgens())
+
+        return result
+
+    finally:
+        events.set_event_loop(None)
+        loop.close()