chore: Automated docker builds

Author: 0ffz

.github/workflows/publish-docker-image.yml

@@ -0,0 +1,43 @@
+name: build java
+on:
+  push:
+    branches:
+      - master
+    paths-ignore:
+      - README.md
+      - docs
+      - .github/workflows/docs.yml
+  workflow_dispatch:
+
+env:
+  REGISTRY: ghcr.io
+
+jobs:
+  push:
+    name: "Docker image push"
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      packages: write
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Set up JDK
+        uses: actions/setup-java@v3
+        with:
+          distribution: temurin
+          java-version: 25
+
+      - name: Setup Gradle
+        uses: gradle/actions/setup-gradle@v3
+
+      - name: Grant execute permission for gradlew
+        shell: bash
+        run: chmod +x gradlew
+
+      - name: Build
+        run: ./gradlew publishImage
+        env:
+          DOCKER_PROJECT: ${{ env.REGISTRY }}/${{ github.repository }}
+          DOCKER_USERNAME: ${{ github.actor }}
+          DOCKER_PASSWORD: ${{ secrets.GITHUB_TOKEN }}

README.md

@@ -17,8 +17,6 @@ _This applicatcion is built with Ktor and HTMX, with updates sent live using Ser
 
 Clicky runs as a single JVM process, with rooms stored in memory. Restarting the app will kick users back to the homepage, but the upside is no database or filesystem setup is needed at all! We provide a Docker image for easy setup, a full list of environment variables with descriptions can be found in [application.yaml](https://github.com/0ffz/Clicky/blob/master/server/src/main/resources/application.yaml)
 
-`TODO: setup automated builds via github action`
-
 ```yaml
 services:
   clicky:
@@ -37,6 +35,12 @@ To get HTTPS encryption on your website, use a reverse proxy such as traefik, ca
 
 # Development
 
+Build commands:
+
+- Run local server: `./gradlew run`
+- Build Docker image: `./gradlew publishImageToLocalRegistry`
+
+## Architecture
 _This app was originally an experiment rewriting an old [Django](https://github.com/0ffz/Clicky-django) application I made using HTMX, I will try to link to a blog post here once finished._ Below is a quick overview of the app architecture:
 
 - Ktor serves pages using the Kotlin HTML DSL. They include HTMX as a small JavaScript dependency and style components using Tailwind classes (with the stylesheet generated by a small Gradle plugin.)

server/build.gradle.kts

@@ -69,6 +69,11 @@ ktor {
     docker {
         jreVersion = JavaVersion.VERSION_25
         localImageName = "ghcr.io/0ffz/clicky"
+        externalRegistry = io.ktor.plugin.features.DockerImageRegistry.externalRegistry(
+            username = providers.environmentVariable("DOCKER_USERNAME"),
+            password = providers.environmentVariable("DOCKER_PASSWORD"),
+            project = providers.environmentVariable("DOCKER_PROJECT")
+        )
     }
 }