Added resources for next blog 'Spring Boot Docker Best Practices'

Author: mydeveloperplanet

Dockerfiles/6-Dockerfile-healthcheck

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+FROM eclipse-temurin:17.0.5_8-jre-alpine@sha256:02c04793fa49ad5cd193c961403223755f9209a67894622e05438598b32f210e
+WORKDIR /opt/app
+RUN addgroup --system javauser && adduser -S -s /usr/sbin/nologin -G javauser javauser
+ARG JAR_FILE
+COPY target/${JAR_FILE} app.jar
+RUN chown -R javauser:javauser .
+USER javauser
+HEALTHCHECK --interval=30s --timeout=3s --retries=1 CMD wget -qO- http://localhost:8080/actuator/health/ | grep UP || exit 1
+ENTRYPOINT ["java", "-jar", "app.jar"]

Dockerfiles/7-Dockerfile-multi-stage-build

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+FROM maven:3.8.6-eclipse-temurin-17-alpine@sha256:e88c1a981319789d0c00cd508af67a9c46524f177ecc66ca37c107d4c371d23b AS builder
+WORKDIR /build
+COPY . .
+RUN mvn clean package -DskipTests
+
+FROM eclipse-temurin:17.0.5_8-jre-alpine@sha256:02c04793fa49ad5cd193c961403223755f9209a67894622e05438598b32f210e
+WORKDIR /opt/app
+RUN addgroup --system javauser && adduser -S -s /usr/sbin/nologin -G javauser javauser
+COPY --from=builder /build/target/mydockerbestpracticesplanet-0.0.1-SNAPSHOT.jar app.jar
+RUN chown -R javauser:javauser .
+USER javauser
+HEALTHCHECK --interval=30s --timeout=3s --retries=1 CMD wget -qO- http://localhost:8080/actuator/health/ | grep UP || exit 1
+ENTRYPOINT ["java", "-jar", "app.jar"]

Dockerfiles/8-Dockerfile-spring-boot-docker-layers

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+FROM eclipse-temurin:17.0.4.1_1-jre-alpine@sha256:e1506ba20f0cb2af6f23e24c7f8855b417f0b085708acd9b85344a884ba77767 AS builder
+WORKDIR application
+ARG JAR_FILE
+COPY target/${JAR_FILE} app.jar
+RUN java -Djarmode=layertools -jar app.jar extract
+
+FROM eclipse-temurin:17.0.4.1_1-jre-alpine@sha256:e1506ba20f0cb2af6f23e24c7f8855b417f0b085708acd9b85344a884ba77767
+WORKDIR /opt/app
+RUN addgroup --system javauser && adduser -S -s /usr/sbin/nologin -G javauser javauser
+COPY --from=builder application/dependencies/ ./
+COPY --from=builder application/spring-boot-loader/ ./
+COPY --from=builder application/snapshot-dependencies/ ./
+COPY --from=builder application/application/ ./
+RUN chown -R javauser:javauser .
+USER javauser
+HEALTHCHECK --interval=30s --timeout=3s --retries=1 CMD wget -qO- http://localhost:8080/actuator/health/ | grep UP || exit 1
+ENTRYPOINT ["java", "org.springframework.boot.loader.JarLauncher"]

compose.yml

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+services:
+  dockerbestpractices:
+    image: mydeveloperplanet/dockerbestpractices:0.0.1-SNAPSHOT
+
+  autoheal:
+    image: willfarrell/autoheal:1.2.0
+    restart: always
+    environment:
+      AUTOHEAL_CONTAINER_LABEL: all
+    volumes:
+      - type: bind
+        source: /var/run/docker.sock
+        target: /var/run/docker.sock

src/main/java/com/mydeveloperplanet/mydockerbestpracticesplanet/DownHealthIndicator.java

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+package com.mydeveloperplanet.mydockerbestpracticesplanet;
+
+import org.springframework.boot.actuate.health.Health;
+import org.springframework.boot.actuate.health.HealthIndicator;
+import org.springframework.stereotype.Component;
+
+@Component
+public class DownHealthIndicator implements HealthIndicator {
+
+    private int counter;
+
+    @Override
+    public Health health() {
+        counter++;
+        Health.Builder status = Health.up();
+        if (counter == 5) {
+            status = Health.down();
+            counter = 0;
+        }
+        return status.build();
+    }
+}