GitBucket has the plug-in system to extend itself from outside of GitBucket. In this entry, I show how to create a simple GitBucket plug-in.

Create project

First, create a new sbt project with the following build.sbt and project/plugins.sbt:

  • build.sbt

    name := "gitbucket-helloworld-plugin"
    organization := "io.github.gitbucket"
    version := "1.0.0"
    scalaVersion := "2.13.3"
    gitbucketVersion := "4.35.3" // Update to the latest GitBucket version
  • project/plugins.sbt

    addSbtPlugin("io.github.gitbucket" % "sbt-gitbucket-plugin" % "1.5.0")

sbt-gitbucket-plugin adds necessary library dependencies to the project automatically, and also provide some useful configuration and sbt task for GitBucket plugin development.

Plug-in definition

Next, create Plugin which extends gitbucket.core.plugin.Plugin under /src/main/scala. Declare plug-in metadata and extension details in this class.

import io.github.gitbucket.helloworld.controller.HelloWorldController
import io.github.gitbucket.solidbase.model.Version

class Plugin extends gitbucket.core.plugin.Plugin {
  override val pluginId: String = "helloworld"
  override val pluginName: String = "HelloWorld Plugin"
  override val description: String = "First example of GitBucket plug-in"
  override val versions: List[Version] = List(new Version("1.0.0"))

  override val controllers = Seq(
    "/*" -> new HelloWorldController()

Implement Controller

Then, create HelloWorldController which extends gitbucket.core.controller.ControllerBase under /src/main/io/github/gitbucket/helloworld/controller. It’s a typical Scalatra controller servlet.

package io.github.gitbucket.helloworld.controller

import gitbucket.core.controller.ControllerBase

class HelloWorldController extends ControllerBase {
    "Hello World!"

In this example, HelloWorldController returns a plain text response. Of course, it’s also possible to return any other type of response such as HTML rendered by Twirl template or JSON.

Install and Test

Run sbt assembly and copy generated /target/scala-2.13/gitbucket-helloworld-plugin-1.0.0.jar to ~/.gitbucket/plugins (If this directory does not exist, create by hand).

Or you can just run sbt install to generate the plugin jat file and copy it to GitBucket plugin directory at once.

After copying the plugin jar file, start GitBucket and access to http://localhost:8080/helloworld by your web browser, you will see Hello World! response. Note that if you copy the plugin jar file again, the plugin is reloaded automatically so that you don’t need to restart GitBucket when you updated plugins.

Next step

You can find a complete project which is explained in this article here. You can start plugin development from this project.

Furthermore, you can find practical plugins at gitbucket community plugins. Check source code of these plugins to know more details about GitBucket plug-in.