plugin-ext: lookup plugins in user home dir

[paul-marechal]

Signed-off-by: Paul Maréchal paul.marechal@ericsson.com

What it does

Allow configuring plugin locations via backend configuration, and look into the user home by default.

How to test

• After running yarn, move/rename the plugins directory.
• Start the browser application, no plugin should be found.
• Go to examples/browser/src-gen/main.js and edit:

BackendApplicationConfigProvider.set({
    plugins: ['local-dir:../../<renamed-plugin-folder>']
});

• Start the browser application, plugins should be found.
• Move the plugin folder to:
  • Windows: C:\Users\<username>\AppData\Roaming\.theia\extensions
  • Linux: /home/<username>/.theia/extensions
• Start the browser application, plugins should be found.
• Repeat the steps for the electron application.

Review checklist

• as an author, I have thoroughly tested my changes and carefully followed the review guidelines

Reminder for reviewers

• as a reviewer, I agree to behave in accordance with the review guidelines

[paul-marechal]

Or is it better to have applications/clients do these extra lookups by themselves?

[benoitf]

Hello,
I think it may be confusing if plug-ins are looked into something called extensions ?

besides the name I would say that it's up to the Application to setup this (they can also just define THEIA_PLUGINS env var in their startup to any location) like local-dir://${HOME}/.theia/plugins or whatever

[akosyakov]

I don't understand what it tries to solve and why we need yet another way to specify plugin dir. What we need for browser/electron that extensions are preserved on theia restart, for it indeed extension should be loaded from theia dir always, but also stored there on installation. In order to work on it first #6650 should be landed.

[paul-marechal]

Makes sense, thanks.