Building a firmware with asyncio included

[DrTom]

We want to build a firmware with the asyncio module from micropython included.

To that end we created a symlink from bricks/_common/modules/uasyncio to ../../../micropython/extmod/uasyncio and adjusted manifest.py by adding include("./modules/uasyncio"). We used this approach because the autodetection in manifest.py does not work for files in directories and and the directive ("$(MPY_DIR)/extmod/uasyncio") from the original micropython seems not to work. It says MPY_DIR is not set.

When we compile the firmware we can see the following in the log:

Including foo as a module.
MPY uasyncio/__init__.py
MPY uasyncio/core.py
MPY uasyncio/event.py
MPY uasyncio/funcs.py
MPY uasyncio/lock.py
MPY uasyncio/stream.py
MPY foo.py
GEN build/frozen_content.c

so far so goo. foo.py ist just for testing to see if that works.

Now, when running the firmware using foo works:

>>> import foo
>>> print(foo.PI)
3.14

however, when trying to import (u)asyncio we get an ImportError.

>>> import asyncio
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ImportError: no module named 'asyncio'
>>> import uasyncio
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ImportError: no module named 'uasyncio'

What do we need to do to build asyncio (or for that matter any other micropython library) into the firmware?

[laurensvalk]

Since last week, https://beta.pybricks.com/ includes support for asynchronous multitasking. See multitask and run_task in the tools module.

It does not have all of the asyncio module (hence the missing uasyncio error), but it should be enough to do most things. If you think something important is missing, do feel free to let us know.

[DrTom]

OK, thank you. We will have a look at this.

I am still curios why our approach including asyncio did not work and what would be necessary to include a larger module based on a directory structure. Do you have any hints?

[laurensvalk]

As far as I know, uasyncio is partially implemented in C, not fully as a Python module, so I don't know if this is expected to work.

Modules are included via the manifest file. See this link for more details and possibilities: https://docs.micropython.org/en/latest/reference/manifest.html

More generally, it sounds like you'd like a package with submodules? If you look into this, do let us know what you find :)

[laurensvalk]

The main question here seems to be answered, so we can close this issue. If specific changes are required for certain build steps like the Makefile, feel free to open a dedicated issue.