feat: reduce image size with alpine and amazon corretto jdk

Author: osahner

Dockerfile

@@ -1,4 +1,22 @@
-FROM eclipse-temurin:17-jdk-focal
+FROM amazoncorretto:17-alpine as corretto-jdk
+
+# required for strip-debug to work
+RUN apk add --no-cache binutils
+
+# Build small JRE image
+RUN jlink \
+         --add-modules ALL-MODULE-PATH \
+         --strip-debug \
+         --no-man-pages \
+         --no-header-files \
+         --compress=2 \
+         --output /jre
+
+FROM alpine:latest
+ENV JAVA_HOME=/jre
+ENV PATH="${JAVA_HOME}/bin:${PATH}"
+
+COPY --from=corretto-jdk /jre $JAVA_HOME
 
 ARG JAR_FILE
 ARG SPRING_BOOT_VERSION
@@ -7,8 +25,8 @@ LABEL org.opencontainers.image.authors="Oliver Sahner <[email protected]>"
 LABEL org.springframework.boot="${SPRING_BOOT_VERSION}"
 
 RUN mkdir /opt/app
-RUN addgroup --system --gid 1001 spring
-RUN adduser --system --no-create-home --uid 1001 --gid 1001 spring
+RUN addgroup -g 1001 -S spring
+RUN adduser -u 1001 -S spring -G spring
 RUN chown spring:spring /opt/app
 USER spring
 

contributed/buildDocker.sh

@@ -33,5 +33,5 @@ if [[ $p -eq 1 ]]; then
   PLATFORM="linux/amd64"
 fi
 echo -e " ${color_light_cyan}+ for platform ${PLATFORM}${color_restore}"
-docker build --build-arg JAR_FILE="${JAR_FILE}" --build-arg SPRING_BOOT_VERSION="${SPRING_BOOT_VERSION}" \
+DOCKER_BUILDKIT=1 docker build --build-arg JAR_FILE="${JAR_FILE}" --build-arg SPRING_BOOT_VERSION="${SPRING_BOOT_VERSION}" \
   --platform=${PLATFORM} --no-cache --pull --rm -f Dockerfile -t "${GROUPID}/${ARTIFACTID}:${VERSION}" .

pom.xml

@@ -5,13 +5,13 @@
   <parent>
     <groupId>org.springframework.boot</groupId>
     <artifactId>spring-boot-starter-parent</artifactId>
-    <version>3.0.2</version>
+    <version>3.0.4</version>
     <relativePath/> <!-- lookup parent from repository -->
   </parent>
 
   <groupId>osahner</groupId>
   <artifactId>kotlin-spring-boot-rest-jpa-jwt-starter</artifactId>
-  <version>0.9.1-SNAPSHOT</version>
+  <version>0.9.2-SNAPSHOT</version>
   <packaging>jar</packaging>
 
   <name>kotlin spring-boot 2 rest/jpa/jwt starter</name>
@@ -22,7 +22,7 @@
     <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
 
     <java.version>17</java.version>
-    <kotlin.version>1.8.0</kotlin.version>
+    <kotlin.version>1.8.10</kotlin.version>
 
     <dockerfile-maven.version>1.4.13</dockerfile-maven.version>
     <jacoco-maven-plugin.version>0.8.7</jacoco-maven-plugin.version>