Optimize built image

Use multi-stage build to only have eclipse-temurin:21-jre-alpine
being used when running the app. Also don't copy the entire
target directory but rather just use the zip with only the
necessary files needed to run the application.

JIRA: LIGHTY-353
Signed-off-by: tobias.pobocik <tobias.pobocik@pantheon.tech>

Author: Tobianas

Dockerfile

@@ -12,8 +12,20 @@ RUN mvn install -DskipTests
 
 WORKDIR /lighty-netconf-simulator/examples/devices/lighty-network-topology-device
 
-RUN cp target/lighty-network-topology-device-$VERSION.jar target/lighty-network-topology-device.jar
+RUN unzip target/lighty-network-topology-device-$VERSION-bin.zip -d target/
+
+RUN mv target/lighty-network-topology-device-$VERSION target/lighty-network-topology-device
+RUN mv target/lighty-network-topology-device/lighty-network-topology-device-$VERSION.jar target/lighty-network-topology-device/lighty-network-topology-device.jar
+
+FROM eclipse-temurin:21-jre-alpine
+
+ARG VERSION
+
+COPY --from=build /lighty-netconf-simulator/examples/devices/lighty-network-topology-device/target/lighty-network-topology-device /app/target
+COPY --from=build /lighty-netconf-simulator/examples/devices/lighty-network-topology-device/src/main/resources /app/target/resources
+
+WORKDIR /app/target
 
 EXPOSE 17380
 
-ENTRYPOINT ["java", "-jar", "target/lighty-network-topology-device.jar"]
+ENTRYPOINT ["java", "-jar", "lighty-network-topology-device.jar"]