Env variables used in JAVA_OPTIONS are not expanded

[cescoffier]

For example, if I pass -Dsome-property=${CONTAINER_CORE_LIMIT:-1} in the JAVA_OPTIONS, the env variable is not expanded.

[rhuss]

You mean for the variables set by the script itself ?

When calling a unix command / shell it's always the caller that expand the env var, so it should arrive already resolved when evaluated by the script. It is a very common convention that you do not an extra evaluation on the values of provided arguments or values of environment variables (which can lead to nasty side effects, too).

However for the variables determined and set by script itself I see your point (like CONTAINER_CORE_LIMIT etc) as it cannot expanded from the outside of course.

I agreed that we should allow a special treatment for these variables.

[cescoffier]

Typically, I need to configure the number of Vert.x event loop based on the container core limit (not necessary set, so my default value). So, my approach was to extend the Vert.x generator (from the fabric8 mavne plugin) with -Dvertx.options.eventLoopPoolSize=${CONTAINER_CORE_LIMT:-2} but it does not get expanded.

Actually, the computation should be 2 * CONTAINER_CORE_LIMIT. So I probably would have to use expr which may lead to another issue.