Skip to content

dkandalov/live-plugin

Repository files navigation

Build Status

LivePlugin

Plugin for IntelliJ-based IDEs to create plugins at runtime using Kotlin and Groovy. To install search for "LivePlugin" in IDE Preferences -> Plugins -> Marketplace or use the "Install" button on the Plugin Marketplace website.

demo

Why?

  • Minimal setup — no need to set up a separate project for plugin development
  • Fast feedback loop — plugins are (re)loaded in the same JVM instance as IDE without restart
  • Usable IDE API — LivePlugin has a small API with entry points for common IDE APIs

Examples

Hello world (Groovy):

import static liveplugin.PluginUtil.show
show("Hello world") // Shows balloon notification popup with "Hello world" text

Insert New Line Above action (Kotlin):

import com.intellij.openapi.actionSystem.AnActionEvent
import liveplugin.*

// Action to insert a new line above the current line.
// Based on this post https://martinfowler.com/bliki/InternalReprogrammability.html
// Note that there is also built-in "Start New Line Before Current" action (ctrl+alt+enter).
registerAction(id = "Insert New Line Above", keyStroke = "ctrl alt shift ENTER") { event ->
    val project = event.project ?: return@registerAction
    val editor = event.editor ?: return@registerAction
    executeCommand(editor.document, project) { document ->
        val caretModel = editor.caretModel
        val lineStartOffset = document.getLineStartOffset(caretModel.logicalPosition.line)
        document.insertString(lineStartOffset, "\n")
        caretModel.moveToOffset(caretModel.offset + 1)
    }
}
show("Loaded 'Insert New Line Above' action<br/>Use 'ctrl+alt+shift+Enter' to run it")

Getting started

Make sure "hello world" works fine:

  • In the Plugins tool window select "hello-world" plugin and click "Run" button to execute the plugin (Run Plugin action with ctrl+shift+L or alt+C, alt+E shortcut). It should display a message.
  • Make a small modification in plugin.groovy/plugin.kts and rerun the plugin. On the second run, the previous version of the plugin will be unloaded before the code is evaluated again.
  • Modify plugin.groovy/plugin.kts file again so that it fails to compile/run. You should see an error message in the Run tool window.
  • Note that plugins are just folders with plugin.groovy or plugin.kts scripts as entry points. This means that you can, for example, copy the path to the plugin folder using the Copy Path action (ctrl/cmd+alt+C shortcut).

Try bundled examples:

  • In the Plugins tool window click the "Plus" button (Add Plugin action) to add Kotlin or Groovy examples.
  • It might be useful to install Kotlin or Groovy plugin if your IDE supports them.

Take a look at settings in the Plugins toowindow:

  • Run Plugins on IDE Start — run all plugins on IDE start.
  • Run Project Specific Plugins — run all plugins in .live-plugins project directory when the project is opened and unload them when the project is closed.
  • Add LivePlugin and IDE Jars to Project — useful for Groovy plugins to get auto-completion and code navigation in plugin code. (Adding jars unrelated to your project is a bit of a hack but there seems to be no major problems with it.) Note that Kotlin plugins should have auto-completion and code navigation without it.

Learn more about IntelliJ API:

Once your plugin has grown, you can move it to a proper plugin project still using live plugin for reloading and maybe then convert it to become a dynamic plugin.

If something doesn't work or doesn't make sense, please feel free to ask in #plugin-live-plugin channel on Jetbrains platform slack or report an issue (it's ok to report an issue even if it's just a question).

How does LivePlugin work?

Overall, the idea is just to load and run plugin Groovy or Kotlin classes in the IDE JVM at runtime. More specifically the steps are:

  • if there is an instance of pluginDisposable from previous execution, then dispose it (on EDT)
  • create a new classloader with dependencies on other plugins and jars (on a background thread)
  • compile code if necessary and load classes in the classloader (on a background thread)
  • run the plugin code (on EDT)

This means that plugin code can use any internal IDE API and observe/change IDE state. There are some limitations of course, such as final fields and IDE APIs which are not designed to be re-initialized.

Most IntelliJ-based IDEs come with a bundled Groovy jar which is used for loading and running live plugins (otherwise, the groovy-all jar will be downloaded). LivePlugin uses its own version of Kotlin stdlib and compiler because the version bundled with IDEs changes quite often and seems to be harder to rely on.

Some practical use cases

  • project-specific workflow automation
  • integrating shell scripts with IDE
  • prototyping plugins, experimenting with IntelliJ API

More examples

Similar plugins

The idea of running code inside IntelliJ is not original. There are/were similar plugins:

Contributing

Please see CONTRIBUTING.md.