This is a general notice for anyone who just worked through an issue I’d faced.
None of my ENVs were being passed to my containers on build, seemingly becoming undefined in the process.
The culprit was a multi-stage Docker build. This might be common knowledge for some but the only (easiest) way to pass them was an ARG, which when used in a multi-stage build must be recalled.
Search params: [ docker, multi-stage, env, not working, environment variable, build stage ]