Dockerfile Spring Boot property from variable not working

Question

I can't seem to get Spring boot properties to work via variable in my Dockerfile. This is what I am doing:

ENTRYPOINT exec java -Dapp-version=$app_version -jar /app.jar

If I do RUN echo "App Version: $app_version" inside of my Dockerfile then I get then I get the correct output like App Version: 1.70.0 .

If I manually put the version like this: ENTRYPOINT exec java -Dapp-version=1.70.0 -jar /app.jar then the value is injected correctly.

In fact, if I do RUN echo "ENTRYPOINT exec java -Dapp-version=$app_version -jar /app.jar" then I get output like

Step 9/10 : RUN echo "ENTRYPOINT exec java -D******ion=$app_version -jar /app.jar"
 ---> Running in b6c3cd9bb69a
ENTRYPOINT exec java -D******ion=1.70.0 -jar /app.jar

The value inside of Spring is being set as an empty string when I use the Dockerfile variable. When I hard code it to 1.70.0 then it is being set correctly. What am I missing?

I have tried many different things including using {}, quotes, etc.

Edit: Added Dockerfile

FROM java:8
ARG app_version

RUN echo -------------------
RUN echo "App Version: $app_version"
RUN echo -------------------

VOLUME /tmp
COPY ./build/libs/mango-sticky-rice-1.0.0-SNAPSHOT.jar /app.jar
RUN bash -c 'touch /app.jar'

ENTRYPOINT exec java -Dapp-version=$app_version -jar /app.jar

Answer 1

I've eddited this answer:

I think this might work

ENTRYPOINT ["java", "-Dapp-version=$app_version", "-jar", "/app.jar"]

Answer 2

This answer worked: https://stackoverflow.com/a/49889134/3088642 . This is what my Dockerfile looks like:

FROM java:8
ARG app_version

RUN echo -------------------
RUN echo "App Version: ${app_version}"
RUN echo -------------------

VOLUME /tmp
COPY ./build/libs/mango-sticky-rice-1.0.0-SNAPSHOT.jar /app.jar
RUN bash -c 'touch /app.jar'

RUN echo "#!/bin/bash \n java -Dapp-version=${app_version} -jar /app.jar" > ./entrypoint.sh
RUN chmod +x ./entrypoint.sh

RUN cat ./entrypoint.sh

ENTRYPOINT ["./entrypoint.sh"]