Implement Custom Facets

[dgeissl]

As mentioned here #36 many users have the need for custom Facets and many of them can not be autodetected.

So i was wondering if there is a way to provide pull requests that support the types of Facets we'd like to support or even enhance the plugin in our own plugin to add even more (non-public) Facet types.

From the Plugins implementation side a facet seems to be just a map (containing other maps and so on), so I tried adding such a custom Facet in a local Plugin:

private void configureIdea(Project project) {
        final IdeaModel model = project.getExtensions().getByType(IdeaModel.class);
        ModuleSettings moduleSettings = ProjectUtils.getExtensionOfType(model.getModule(), ModuleSettings.class);
        moduleSettings.getFacets().create("ejb", EjbFacet.class);
    }

    public static class EjbFacet implements org.jetbrains.gradle.ext.Facet {
        String name = "EJB";
        String type = "ejb";

        public String getType() {
            return type;
        }
        public String getName() {
            return name;
        }
        public Map<String, ?> toMap() {
            Map<String, Object> map = new HashMap<>();
            map.put("type", type);
            map.put("name", name);
            return map;
        }
    }

Unfortunately this did not work - or had no visible effect on the modules settings or the created iml files. So I wonder where is that magic happening that applies the setting from this plugin into intellij? If we know the interface we may provide the pull requests or even the configuration on our own and help this plugin to grow.

[ingokegel]

In #127 I did this for web resource directories in the web facet. Apart from support in this Gradle plugin, it also needs explicit support in the IDE using the externalSystem.facetConfigurationImporter extension point, so you have to write an IDEA plugin for that.

[nskvortsov]

@dgeissl indeed, you need to provide the support on IDEA side as well.
This extensibility is mostly targeting third party plugins that would like to have their facets configured via IDEA Ext dsl in build.gradle file. For IDEA's built-in/bundled facets, I'd expect native sync to work. Please report an issue to our Youtrack instance if some bundled facet does not get detected (without IDEA Ext)

[dgeissl]

@nskvortsov while the facet autodetection is ok - it's still annoying if you have to wait for intellij to detect the projects nature and click the automatic configuration to happen.
The gradle build can configure it right away and in many cases even better as it knows best what deployment descriptors to use and where to find them (even if they haven't been created yet).

If I get it correctly then everything that has a autodetect feature does not have a tooling api importer?

[nskvortsov]

Acutally, almost none have a tooling api importer at the moment. Regardless of autodetect implementation.