This is a very large refactoring which aims at making Tutor both more
extendable and more generic. Historically, the Tutor plugin system was
designed as an ad-hoc solution to allow developers to modify their own
Open edX platforms without having to fork Tutor. The plugin API was
simple, but limited, because of its ad-hoc nature. As a consequence,
there were many things that plugin developers could not do, such as
extending different parts of the CLI or adding custom template filters.
Here, we refactor the whole codebase to make use of a generic plugin
system. This system was inspired by the Wordpress plugin API and the
Open edX "hooks and filters" API. The various components are added to a
small core thanks to a set of actions and filters. Actions are callback
functions that can be triggered at different points of the application
lifecycle. Filters are functions that modify some data. Both actions and
filters are collectively named as "hooks". Hooks can optionally be
created within a certain context, which makes it easier to keep track of
which application created which callback.
This new hooks system allows us to provide a Python API that developers
can use to extend their applications. The API reference is added to the
documentation, along with a new plugin development tutorial.
The plugin v0 API remains supported for backward compatibility of
existing plugins.
Done:
- Do not load commands from plugins which are not enabled.
- Load enabled plugins once on start.
- Implement contexts for actions and filters, which allow us to keep track of
the source of every hook.
- Migrate patches
- Migrate commands
- Migrate plugin detection
- Migrate templates_root
- Migrate config
- Migrate template environment globals and filters
- Migrate hooks to tasks
- Generate hook documentation
- Generate patch reference documentation
- Add the concept of action priority
Close #499.
`upgrade` had several issues, which are summarized here:
https://discuss.overhang.io/t/confusing-instructions-during-upgrade/2281/7
- The docs say that you should run quickstart, but what most people will see is
the big command tutor local upgrade --from=lilac verbatim paragraph.
- The local upgrade command should be very explicit about the fact that users
need to run quickstart.
- Maybe the name of the local upgrade command should be improved.
- When upgrading tutor from one major release to the next, there should be a
more explicit warning to inform users of what they are doing (see this other
conversation 1)
- We should tell people that they almost certainly need to enable the tutor and
the mfe plugins, if they are not enabled during upgrade.
- A link to all of the breaking changes from the changelog should be
prominently displayed during upgrade.
- The docs should emphasize that upgrading from one major release to the next
is potentially a risky endeavor and that downgrading is not possible. The docs
should also link to the changelog.
This commit has grown slightly beyond the intended scope, but the changes should be mostly positive.
Régis Behmo
Florian Haas