feat: dockerfile

Author: felipementel

docker/Dockerfile

@@ -0,0 +1,64 @@
+# ──────────────────────────────────────────────────────────────
+# Stage 1 – dependency cache
+# Only re-runs when pom.xml changes; Maven deps are cached.
+# ──────────────────────────────────────────────────────────────
+FROM eclipse-temurin:21-jdk-alpine AS deps
+
+WORKDIR /build
+
+COPY mvnw .
+COPY .mvn .mvn
+COPY pom.xml .
+
+RUN chmod +x mvnw && \
+    ./mvnw dependency:go-offline -B
+
+# ──────────────────────────────────────────────────────────────
+# Stage 2 – compile and package
+# Only re-runs when source changes.
+# ──────────────────────────────────────────────────────────────
+FROM deps AS build
+
+COPY src ./src
+
+RUN ./mvnw clean package -DskipTests -B
+
+# ──────────────────────────────────────────────────────────────
+# Stage 3 – extract Spring Boot layers
+# Splits the fat JAR into 4 independent Docker layers so that
+# library changes don't invalidate the application-code layer.
+# ──────────────────────────────────────────────────────────────
+FROM eclipse-temurin:21-jdk-alpine AS layers
+
+WORKDIR /build
+
+COPY --from=build /build/target/*.jar app.jar
+
+RUN java -Djarmode=tools -jar app.jar extract \
+      --layers \
+      --launcher \
+      --destination extracted
+
+# ──────────────────────────────────────────────────────────────
+# Stage 4 – minimal runtime image (JRE only, no JDK)
+# ──────────────────────────────────────────────────────────────
+FROM eclipse-temurin:21-jre-alpine AS runtime
+
+RUN addgroup -S appgroup && \
+    adduser -S appuser -G appgroup
+
+WORKDIR /app
+
+# Most-stable layers first → best Docker cache hit rate
+COPY --from=layers /build/extracted/dependencies/          ./
+COPY --from=layers /build/extracted/spring-boot-loader/    ./
+COPY --from=layers /build/extracted/snapshot-dependencies/ ./
+COPY --from=layers /build/extracted/application/           ./
+
+RUN chown -R appuser:appgroup /app
+
+USER appuser
+
+EXPOSE 8080
+
+ENTRYPOINT ["java", "org.springframework.boot.loader.launch.JarLauncher"]