dockerfile run app as spring user

build.Dockerfile

@@ -25,7 +25,7 @@
 # syntax=docker/dockerfile:1
 
 ################################################################################
-# BUILD STAGE
+# BUILD JAR
 
 FROM maven:3-eclipse-temurin-21-alpine AS builder
 
@@ -37,10 +37,15 @@ ADD . /builder
 RUN mvn --quiet --batch-mode --update-snapshots --fail-fast -DskipTests package
 
 ################################################################################
-# RUN STAGE
+# BUILD IMAGE
 
 FROM eclipse-temurin:21-jdk-alpine
 
+# add non-root user to run the app
+# https://spring.io/guides/gs/spring-boot-docker
+RUN addgroup -S spring && adduser -S spring -G spring
+USER spring:spring
+
 WORKDIR /fdp
 
 COPY --from=builder /builder/target/fdp-spring-boot.jar /fdp/app.jar