Dockerfile

# Multi-stage build for Data Lake Receiver
# Stage 1: Build the application
FROM maven:3.9-eclipse-temurin-17-alpine AS builder

WORKDIR /build

# Copy Maven files for dependency caching
COPY pom.xml .

# Download dependencies (cached layer)
RUN mvn dependency:go-offline -B

# Copy source code
COPY src ./src

# Build the application (skip tests for faster builds)
RUN mvn clean package -DskipTests -B

# Stage 2: Runtime image
FROM eclipse-temurin:17-jre-alpine

# Set working directory
WORKDIR /app

# Install curl for healthchecks
RUN apk add --no-cache curl

# Create non-root user for security
RUN addgroup -g 1000 appuser && \
    adduser -D -u 1000 -G appuser appuser && \
    mkdir -p /app/data/files && \
    chown -R appuser:appuser /app

# Copy the JAR from builder stage
COPY --from=builder /build/target/datalake-receiver-*.jar app.jar

# Change ownership
RUN chown appuser:appuser app.jar

# Switch to non-root user
USER appuser

# Expose the application port
EXPOSE 4000

# Health check
HEALTHCHECK --interval=30s --timeout=10s --start-period=40s --retries=3 \
  CMD curl -f http://localhost:4000/health || exit 1

# Run the application
ENTRYPOINT ["java", "-jar", "app.jar"]