Fix the asyncio example ioc, and documentation

Also tweak the wording on the exception logging

Author: AlexanderWells-diamond

CHANGELOG.rst

@@ -16,6 +16,7 @@ Added:
 
 Fixed:
 
+- `Update asyncio example to use dispatcher for custom function <../../pull/94>`_
 - `Passing a custom asyncio event loop into the AsyncioDispatcher causes methods to never run <../../pull/96>`_
 
 4.0.2_ - 2022-06-06

docs/examples/example_asyncio_ioc.py

@@ -23,7 +23,7 @@ async def update():
         ai.set(ai.get() + 1)
         await asyncio.sleep(1)
 
-asyncio.run_coroutine_threadsafe(update(), dispatcher.loop)
+dispatcher(update)
 
 # Finally leave the IOC running with an interactive shell.
 softioc.interactive_ioc(globals())

docs/how-to/use-asyncio-in-an-ioc.rst

@@ -21,8 +21,9 @@ this.
 
 The ``async update`` function will increment the value of ``ai`` once per second,
 sleeping that coroutine between updates.
-Note that we run this coroutine in the ``loop`` of the ``dispatcher``, and not in the
-main event loop.
+Note that we pass this coroutine to the ``dispatcher``, which will execute it in the
+dispatcher's own event loop and not in the main event loop. It also provides some logging
+if exceptions occur.
 
 This IOC will, like the one in `../tutorials/creating-an-ioc`, leave an interactive
 shell open. The values of the PVs can be queried using the methods defined in the

softioc/asyncio_dispatcher.py

@@ -46,5 +46,5 @@ async def async_wrapper():
                 if completion:
                     completion(*completion_args)
             except Exception:
-                logging.exception("Exception when awaiting callback")
+                logging.exception("Exception when running dispatched callback")
         asyncio.run_coroutine_threadsafe(async_wrapper(), self.loop)