I am seeing some behavior which I don't know is intended. Seems to be behaving consistently for secrets or env vars.
I can access env/secret vars if I do this. (pseudocode)
image.withEnvVariable("TEST", "TEST").withExec([]string{"sh", "-c", "echo $TEST"})
But not like this
image.withEnvVariable("TEST", "TEST").withExec([]string{"echo", "$TEST"})