Errata

Page one of Ch 2 has a broken link. It's the link to the words "Developing with Curio" at the end of the opening quote on the page. The correct link is to https://oreil.ly/IIV2e.

The callout 'header' says:

await loop.run_in_executor(None, func)

Remove 'await' (code does not have - and should not have - the await keyword.

It is said there that get_running_loop() was introduced in Python 3.8, but it was in Python 3.7

The initial coro.send(None) results in RuntimeError: no running event loop

The example works closer to the text if in Example 3-7 'await asyncio.sleep(1.0)' is changed to 'await asyncio.sleep(0)'.

==================
The __iter__() special method must return an iterable; i.e., an object that implements the __next__() special method. In this case, it’s the same instance, because A itself also implements the __next__() special method.
==================

In place of iterable, it should be iterator. The object implementing __iter__() special method is an iterable but what __iter__() returns is an iterator object, which implements both __iter__() as well as __next__().

The second-to-last line in the example is incorrect:

In print:
value = await redis.get(k)

On execution this fails with:
NameError: name 'redis' is not defined

Should be:
value = await self.redis.get(k)

value = await redis.get(key)

Should be:
value = await self.redis.get(key)

In print:
pending = asyncio.all_tasks()

On execution this fails with:
RuntimeError: no running event loop

Should be:
pending = asyncio.all_tasks(loop=loop)

The ninth line in the example results in an error.

In print:
queue = janus.Queue(loop=loop)

Execution results in this error:
TypeError: __init__() got an unexpected keyword argument 'loop'

Should be:
queue = janus.Queue()

Third line of code on the page is incorrect.

In print:
resp.send(json.dumps(data))

When executed results in the following error:
metric-server.py:33: RuntimeWarning: coroutine 'EventSourceResponse.send' was never awaited
resp.send(json.dumps(data))
RuntimeWarning: Enable tracemalloc to get the object allocation traceback

Should be:
await resp.send(json.dumps(data))