Can we support env var extrapolation ?

[cmoulliard]

Request

Can we support env var extrapolation ?

If I create an .env file with the following env var

REGISTRY_HOST=gitea.cnoe.localtest.me:8443
REG_NAME=http://$REGISTRY_HOST

next source the file dotenv -x .env, then REG_NAME variable appears as such

❯ echo $REG_NAME
http://$REGISTRY_HOST

[SpaceAceMonkey]

I've considered doing this, but I think doing it properly would mean tokenizing the file and writing a complete parser. I could produce a rough version using eval, but eval feels a little sketchy, and I would still have to parse the file if I wanted to avoid problems like recursive references.

Here is a solution that will do what you want for simple cases.

function recurse_dotenv                                                                                                                                                                                                             
  dotenv $argv[1]
  set seconds (date +'%s')
  envsubst < $argv[1] > tmparg$seconds
  dotenv tmparg$seconds
  rm tmparg$seconds
end

recurse_dotenv .env_file

Although it would be a bit kludge-y, I could probably leverage envsubst in the dotenv function in a similar way. I'll give it some thought, but it's more likely to get done if more people show up asking for the same thing.