كتابة Dockerfile لتطبيق Spring Boot

في هذا الدرس

write a small, safe image for a Spring Boot app.

الموضوعات المخطط لها

• A Dockerfile lists the build steps; each instruction makes a layer.
• Multi-stage build: stage one builds the JAR with the JDK; stage two copies only the JAR into a JRE image, so the final image has no build tools.
• Run as a non-root user: USER shop.
• Order instructions so rarely changing layers come first (dependencies before source) for better caching.
• Use a .dockerignore, pin base image versions, and never put secrets in the image.
• Verify the current Temurin/JRE image tags before recording.