Implements the `npm run watch` section of the assets ADR [1], plus some
modifications since I decided to switch from pywatchman to watchdog (see
ADR changes for justification). This will replace `paver watch_assets`
(edx-platform) and `openedx-assets watch-themes` (Tutor).
Specifically, this PR adds three experimental commands:
* `npm run watch-sass` : Watch for Sass changes with watchdog.
* `npm run watch-webpack` : Invoke Webpack-watch for JS changes.
* `npm run watch` : Invoke both `watch-sass` and `watch-webpack` simultaneously.
These commands are only intended to work in development mode. They have
been tested both on bare-metal edx-platform and through `tutor dev run`
on on Linux.
Before removing the "experimental" label, we need to:
* Test through Devstack on Linux.
* Test through Devstack and `tutor dev run` on macOS.
* Test on bare-metal macOS. Might not work, which is OK, but we should
document that.
* Document the commands in edx-platform's README.
* Confirm that this not only works through `tutor dev run`, but also as
a suitable replacement in the `watchthemes` service that Tutor runs
automatically as part of `tutor dev start`. Tweak if necessary.
References:
1. https://github.com/openedx/edx-platform/blob/master/docs/decisions/0017-reimplement-asset-processing.rst
Part of: https://github.com/openedx/edx-platform/issues/31612
During the review of ADR 17 [1], Régis pointed out [2] that the shell script
which replaces Paver's `process_npm_assets` could be automatically invoked as
an NPM post-install hook, ensuring that the step is seamlessly executed whenever
`npm install` is run. I had avoided using that suggestion, as I worried that it
would make it harder to move node_modules out of the edx-platform directory in
Tutor's openedx image.
Since then, two things have changed. Firstly, Tutor v16's new persistent mounts
interface [3] has lessened the importance of moving node_modules. Secondly, I
have realized that using a post-install hook would not preclude us from
modifying the underlying script (scripts/copy-node-modules.sh) to look in an
alternative location for node_modules, should that end up being something we
want to do.
This commit modifies the ADR based on those findings, stubs out Paver's
`process_npm_assets`, and adds the suggested post-install hook and replacement
Bash script.
References:
1. https://github.com/openedx/edx-platform/blob/master/docs/decisions/0017-reimplement-asset-processing.rst
2. https://github.com/openedx/edx-platform/pull/31790#discussion_r1122802492
3. https://github.com/overhangio/tutor/blob/master/CHANGELOG.md#v1600-2023-06-14
Part of: https://github.com/openedx/edx-platform/issues/31604
