Add docker build

.github/workflows/docker.yml

@@ -23,21 +23,9 @@ jobs:
 #          username: ${{ secrets.DOCKERHUB_USERNAME }}
 #          password: ${{ secrets.DOCKERHUB_TOKEN }}
 
-
-      - name: Set up Docker Buildx
+      - name: Set up Docker Build
         uses: docker/setup-buildx-action@v2
 
-      - name: Setup Java 17
-        uses: actions/setup-java@v2
-        with:
-          distribution: temurin
-          java-version: 17
-
-      - name: Build with Gradle
-        uses: gradle/gradle-build-action@67421db6bd0bf253fb4bd25b31ebb98943c375e1
-        with:
-          arguments: build
-
       - name: Build docker image (no push)
         uses: docker/build-push-action@v3
         with:

.gitignore

@@ -1,6 +1,7 @@
 build/
 .gradle/
 .idea/
+.vscode/
 
 /.classpath
 /.project

Dockerfile

@@ -1,6 +1,36 @@
-FROM openjdk:17-alpine
-RUN addgroup -S spring && adduser -S spring -G spring
-USER spring:spring
-ARG JAR_FILE=build/libs/showcase.jar
-COPY ${JAR_FILE} app.jar
-ENTRYPOINT ["java","-jar","/app.jar"]
+FROM eclipse-temurin:17-jdk-jammy AS base
+
+# Use the base image to build a layer with the gradle wrapper. This means we dont need to
+# download the wrapper every time we build the project as the gradle layer is cached by docker
+FROM base as gradle
+
+WORKDIR /app
+
+COPY gradle/ gradle
+COPY gradlew .
+COPY settings.gradle .
+
+RUN ./gradlew tasks
+
+# Use the gradle layer built above as the basis to build the java project. This layer should only
+# get build if the previous layer is build or the files COPYed in are changed
+FROM gradle as builder
+
+WORKDIR /app
+
+COPY build.gradle .
+COPY src/ src
+
+RUN ./gradlew build
+
+# Use the base image and copy in the jar file built in the layer above, meaning we get an image built
+# using the project source code, but with just the packaged code in it.
+FROM base AS runner
+
+WORKDIR /app
+
+ARG JAR_FILE=/app/build/libs/showcase.jar
+
+COPY --from=builder ${JAR_FILE} app.jar
+
+ENTRYPOINT ["java","-jar","app.jar"]

docker-compose.yml

@@ -0,0 +1,12 @@
+version: '3.1'
+
+services:
+
+  showcase:
+    build:
+      context: .
+    ports:
+      - 8080:8080
+      - 8000:8000
+    environment:
+      - JAVA_TOOL_OPTIONS=-agentlib:jdwp=transport=dt_socket,server=y,suspend=n,address=*:8000