# =====================================================================
# 后端镜像：多阶段构建（Maven 编译 -> JRE 运行）
# 构建：docker build -t lab-backend .
# 运行：docker run -p 8080:8080 -e SPRING_PROFILES_ACTIVE=mariadb \
#         -e DB_HOST=host.docker.internal -e DB_USER=lab -e DB_PASSWORD=lab123456 lab-backend
# =====================================================================

# ---------- 构建阶段 ----------
FROM maven:3.9-eclipse-temurin-21 AS build
WORKDIR /build

# 先只复制 pom，利用 Docker 层缓存预热依赖
COPY pom.xml .
RUN mvn -B -q -Dmaven.test.skip=true dependency:go-offline

# 再复制源码并打包（测试在 CI/本地执行，镜像构建跳过）
COPY src ./src
RUN mvn -B -q -Dmaven.test.skip=true package \
    && cp target/*.jar /build/app.jar

# ---------- 运行阶段 ----------
FROM eclipse-temurin:21-jre
WORKDIR /opt/app

# 以非 root 用户运行
RUN useradd -r -u 1001 appuser && chown -R appuser:appuser /opt/app
USER appuser

COPY --from=build --chown=appuser:appuser /build/app.jar /opt/app/app.jar

ENV TZ=Asia/Shanghai \
    JAVA_OPTS="-Xms256m -Xmx512m" \
    SPRING_PROFILES_ACTIVE=dev

EXPOSE 8080

# 容器存活探针：用 bash 的 /dev/tcp 探测端口，避免安装额外工具
HEALTHCHECK --interval=15s --timeout=5s --start-period=40s --retries=5 \
    CMD bash -c 'cat < /dev/null > /dev/tcp/127.0.0.1/8080' || exit 1

ENTRYPOINT ["sh", "-c", "java $JAVA_OPTS -jar /opt/app/app.jar"]