Compute the name of the build jar

- Dockerfile uses pom.xml values from maven
- artifactId, and version used to find built jar

Author: jduimovich

docker/Dockerfile

@@ -18,10 +18,15 @@ COPY pom.xml .
 RUN mvn dependency:go-offline
 
 COPY src src
-RUN mvn package -Dmaven.test.skip=true
+RUN mvn package -Dmaven.test.skip=true 
+# compute the created jar name and put it in a known location to copy to the next layer.
+# If the user changes pom.xml to have a different version, or artifactId, this will find the jar 
+RUN grep version /build/target/maven-archiver/pom.properties | cut -d '=' -f2 >.env-version 
+RUN grep artifactId /build/target/maven-archiver/pom.properties | cut -d '=' -f2 >.env-id
+RUN mv /build/target/$(cat .env-id)-$(cat .env-version).jar /build/target/export-run-artifact.jar
 
 FROM openjdk:11-jdk
-COPY --from=0 /build/target/demo-0.0.1-SNAPSHOT.jar /app/target/demo-0.0.1-SNAPSHOT.jar
+COPY --from=0 /build/target/export-run-artifact.jar  /app/target/export-run-artifact.jar
 
 EXPOSE 8081
-ENTRYPOINT [ "java", "-jar", "/app/target/demo-0.0.1-SNAPSHOT.jar", "--server.port=8081" ]
+ENTRYPOINT [ "java", "-jar", "/app/target/export-run-artifact.jar", "--server.port=8081" ]