Dockerfile Gradle

1# syntax=docker/dockerfile:1
2#
3# Multi-stage JVM image for a Spring Boot Gradle project (Groovy or Kotlin DSL).
4# Gradle counterpart of ./Dockerfile; the toolchain in the build must match the JDK of the build stage.
5# Adapted from jdubois/dr-jskill (Apache-2.0); see references/PROVENANCE.md.
6#
7# - The Boot jar is exploded into layers and started with the JarLauncher.
8# - A minimal runtime is assembled with jlink.
9# - The runtime image is distroless (no shell, non-root, uid 65532).
10# JVM flags go through JAVA_TOOL_OPTIONS because there is no shell.
11#
12#   docker build -f Dockerfile-gradle -t my-spring-app .
13#   docker run --rm -p 8080:8080 my-spring-app
14
15FROM eclipse-temurin:25-jdk-noble AS build
16
17WORKDIR /app
18
19COPY gradlew .
20COPY gradle gradle
21COPY settings.gradle* build.gradle* ./
22RUN chmod +x gradlew && ./gradlew --no-daemon dependencies > /dev/null
23
24COPY src ./src
25RUN ./gradlew --no-daemon bootJar -x test
26
27# bootJar also leaves a *-plain.jar next to the executable jar: skip it.
28RUN cp "$(ls build/libs/*.jar | grep -v -- '-plain\.jar$' | head -1)" app.jar && \
29    java -Djarmode=tools -jar app.jar extract --layers --launcher --destination extracted
30
31# Module list suits typical web + JPA apps; run `jdeps --print-module-deps` if the app fails with NoClassDefFoundError.
32RUN "$JAVA_HOME/bin/jlink" \
33      --add-modules java.base,java.logging,java.naming,java.management,java.management.rmi,java.instrument,java.sql,java.sql.rowset,java.transaction.xa,java.xml,java.xml.crypto,java.desktop,java.security.jgss,java.security.sasl,java.scripting,java.compiler,java.net.http,java.rmi,java.prefs,jdk.unsupported,jdk.crypto.ec,jdk.crypto.cryptoki,jdk.jfr,jdk.management,jdk.management.agent,jdk.attach,jdk.zipfs,jdk.charsets,jdk.net,jdk.security.auth \
34      --strip-debug --no-man-pages --no-header-files --compress=zip-6 \
35      --output /javaruntime
36
37FROM gcr.io/distroless/base-debian12:nonroot
38
39ENV JAVA_HOME=/opt/java
40ENV PATH="$JAVA_HOME/bin:$PATH"
41COPY --from=build /javaruntime $JAVA_HOME
42
43WORKDIR /app
44
45COPY --from=build --chown=65532:65532 /app/extracted/dependencies/ ./
46COPY --from=build --chown=65532:65532 /app/extracted/spring-boot-loader/ ./
47COPY --from=build --chown=65532:65532 /app/extracted/snapshot-dependencies/ ./
48COPY --from=build --chown=65532:65532 /app/extracted/application/ ./
49
50USER nonroot
51
52ENV JAVA_TOOL_OPTIONS="-XX:MaxRAMPercentage=75.0 -XX:+ExitOnOutOfMemoryError"
53
54EXPOSE 8080
55
56ENTRYPOINT ["/opt/java/bin/java", "org.springframework.boot.loader.launch.JarLauncher"]