Make Default ARG as ENV

Let’s say you want to assign some global ARG as the default ENV when you don’t get ENV when running a container you can do this

# ---- Global Variables ----
ARG RELEASE_ENV="preprod"
 
# ---- Base Node ----
FROM node:14-alpine AS base
 
# ---- Release ---
FROM pre-release-$RELEASE_ENV AS release
ARG RELEASE_ENV
ENV APP_ENV=$RELEASE_ENV

Here, in the pre-release$RELEASE_ENV, you assign the global RELEASE_ENV value to the stage and assign this to ENV. you cannot directly access global ARG inside a stage