Using env var or other input in build-args

[supernaut]

I want to pass a specific node version as a build-arg to Nx container. For a lot of other uses I just get the node version from the volta section in my package.json with jq -r < package.json .volta.node to get the exact same version. I would like to have the exact same node version for the container tag in my Dockerfile.

I'm not sure if I'm doing something wrong but I can't seem to get an environment variable into build-args. I've tried putting "NODE_VERSION=${NODE_VERSION}" as a value in build-args and then running container with:

NODE_VERSION=$(jq -r < package.json .volta.node);pnpm nx container app-name

This just sets the value of the NODE_VERSION arg to literally ${NODE_VERSION} without any substitution.

Any ideas?