src/main/docker/Dockerfile.layered

# Ultra-optimized layered build using Distroless
# Expected size: ~180-220MB with better caching

FROM gcr.io/distroless/java21-debian12:nonroot as base

# Stage 1: Extract JAR layers for optimal caching
FROM eclipse-temurin:21-jdk-alpine as extractor
WORKDIR /app
COPY build/libs/*.jar app.jar
RUN java -Djarmode=layertools -jar app.jar extract

# Stage 2: Production image with extracted layers
FROM base
WORKDIR /app

# Copy layers in dependency order (best caching)
COPY --from=extractor /app/dependencies/ ./
COPY --from=extractor /app/spring-boot-loader/ ./
COPY --from=extractor /app/snapshot-dependencies/ ./
COPY --from=extractor /app/application/ ./

EXPOSE 8080

# Optimized JVM settings for micro-containers
ENTRYPOINT ["java", \
    "-XX:+UseContainerSupport", \
    "-XX:MaxRAMPercentage=70.0", \
    "-XX:+UseG1GC", \
    "-XX:+UseStringDeduplication", \
    "-XX:+CompactStrings", \
    "-Xshare:on", \
    "-Djava.security.egd=file:/dev/./urandom", \
    "-Dspring.backgroundpreinitializer.ignore=true", \
    "org.springframework.boot.loader.JarLauncher"]