Dockerfile

# Build stage
FROM gradle:8.5-jdk21 AS build
WORKDIR /app

# Copy gradle files first for dependency caching
COPY build.gradle settings.gradle ./
COPY gradle ./gradle
COPY gradlew gradlew.bat ./

# Make gradlew executable
RUN chmod +x gradlew

# Download dependencies (this layer will be cached)
RUN ./gradlew dependencies

# Copy source code
COPY src ./src

# Build the application
RUN ./gradlew build -x test

# Runtime stage
FROM eclipse-temurin:21-jre-alpine
WORKDIR /app

# Copy the built artifact from build stage
COPY --from=build /app/build/libs/*.jar app.jar

# Add health check
HEALTHCHECK --interval=30s --timeout=3s \
  CMD wget --no-verbose --tries=1 --spider http://localhost:8081/actuator/health || exit 1

# Environment variables with defaults
ENV JAVA_OPTS="-Xms512m -Xmx1024m"
ENV SERVER_PORT=8081

# Expose the application port
EXPOSE ${SERVER_PORT}

# Create a non-root user and switch to it
RUN adduser -D appuser
USER appuser

# Run the application with configurable Java options
ENTRYPOINT ["sh", "-c", "java ${JAVA_OPTS} -jar app.jar"]