# ---- Build stage ----
FROM maven:3.9-eclipse-temurin-17-alpine AS build
WORKDIR /workspace

COPY pom.xml .
RUN mvn dependency:go-offline -q

COPY src ./src
RUN mvn package -DskipTests -q

# ---- Runtime stage ----
FROM eclipse-temurin:17-jre-alpine
WORKDIR /app

# Download OTel Java agent for zero-code auto-instrumentation
RUN wget -q -O /app/otel-agent.jar \
    "https://github.com/open-telemetry/opentelemetry-java-instrumentation/releases/download/v2.5.0/opentelemetry-javaagent.jar"

# Non-root user
RUN addgroup -S appgroup && adduser -S appuser -G appgroup
USER appuser

COPY --from=build /workspace/target/*.jar app.jar

EXPOSE 8080

HEALTHCHECK --interval=30s --timeout=5s --start-period=30s --retries=3 \
    CMD wget -qO- http://localhost:8080/actuator/health | grep -q '"status":"UP"' || exit 1

ENTRYPOINT ["java", "-javaagent:/app/otel-agent.jar", "-jar", "app.jar"]