Dockerfile.06.jlink

# ------------------------------------------------------------
# Stage: build
# Purpose: compile the application and produce a custom runtime via jlink
# Base image: maven:3.9.12-eclipse-temurin-21-noble
# Maven profile: -Pjlink
# Artifact: target/maven-jlink/classifiers/runtime-image (copied to /jre)
# Notes: maven-jlink-plugin produces a modular runtime image and a launcher; verify launcher name
# ------------------------------------------------------------
FROM maven:3.9.12-eclipse-temurin-21-noble AS build

LABEL maintainer="Emmanuel Bruno <emmanuel.bruno@univ-tln.fr>"
LABEL description="Java Hello World - jlink build stage"
LABEL license="MIT"

WORKDIR /app

# Maven Wrapper
COPY mvnw ./
COPY .mvn .mvn
RUN chmod +x mvnw

# Pré-chargement des dépendances (cache Docker)
COPY pom.xml ./
RUN --mount=type=cache,target=/root/.m2 \
    ./mvnw --batch-mode dependency:resolve

# Sources + build jlink
COPY src ./src
RUN --mount=type=cache,target=/root/.m2 \
    ./mvnw --batch-mode -Pjlink clean package

# Ensure jlink output is placed in a stable location inside the build image
# Some maven-jlink-plugin configurations produce the runtime image under
# target/maven-jlink/classifiers/runtime-image; copy its contents to /app/jre
RUN mkdir -p /app/jre \
 && if [ -d target/maven-jlink/classifiers/runtime-image ]; then \
            cp -a target/maven-jlink/classifiers/runtime-image/* /app/jre/ ; \
        fi


# ------------------------------------------------------------
# Stage: runtime
# Purpose: minimal runtime built from the jlink-generated runtime-image
# Base image: debian:bookworm-slim
# Copies: /jre (runtime image) from build stage to /jre in final image
# Notes: jlink runtime is custom and contains only required modules; run the launcher at /jre/bin/hello
# ------------------------------------------------------------
FROM debian:bookworm-slim

LABEL maintainer="Emmanuel Bruno <emmanuel.bruno@univ-tln.fr>"
LABEL description="Java Hello World - jlink runtime"
LABEL version="0.1.0"

# Répertoire applicatif
WORKDIR /app

# Runtime Java custom généré par jlink
COPY --from=build /app/jre /jre

# Utilisateur non-root (bonne pratique)
# Create a dedicated group 'appuser' and add the user to it, then set ownership on /jre
RUN groupadd -g 1001 appuser \
 && useradd --system --uid 1001 -g appuser -s /usr/sbin/nologin appuser \
 && chown -R appuser:appuser /jre \
 && chmod -R go-w /jre

USER appuser

# Exécution via le launcher jlink
# Prefer generic entrypoint: it will detect and exec the jlink launcher (/jre/bin/hello)
COPY entrypoint.sh /usr/local/bin/entrypoint.sh
RUN chmod +x /usr/local/bin/entrypoint.sh || true
ENTRYPOINT ["/usr/local/bin/entrypoint.sh"]