Load .env* files for external command

[ravinggenius]

Goals

CLI command that populates the environment to execute a sub-command.

Non-Goals

I don't know. It seems pretty focused.

Background

I'm trying to reuse the environment processing/loading that Next uses to provide environment variables to other npm scripts or other arbitrary commands. Specifically I have a database migration library (node-pg-migrate) that uses DATABASE_URL=.... to connect to my database. I also have an npm script for migrate set to run node-pg-migrate. I guess what I'm looking for is a Next-aware dotenv "preload", so I can change my migrate script to something like next-env node-pg-migrate and have it export DATABASE_URL to node-pg-migrate. I thought @next/env would have such functionality, but after glancing through the source, it doesn't seem to.

Does anyone know how I can make this work? Currently I'm running DATABASE_URL=... npm run migrate -- up for local development. This isn't ideal because it pollutes my command history with my local database credentials and is a bit much to type every time I need to run a migration.

---

I asked about this on the Discord server a while ago, but it didn't get any traction.

Proposal

Create a CLI wrapper script (next-env) that uses @next/env to populate/export an environment for a given sub-command. Changing NODE_ENV allows loading different environments.

echo "DATABASE_URL=postgres://username:password@host:5432/name-dev" > .env.development
echo "DATABASE_URL=postgres://username:password@host:5432/name-test" > .env.test

# i know $DATABASE_URL is evaluated before echo is executed. what i'm trying to demonstrate is that the echo
# command (internally) would have access to the environment variables that next-env sets up
next-env echo $DATABASE_URL
# postgres://username:password@host:5432/name-dev

NODE_ENV=test next-env echo $DATABASE_URL
# postgres://username:password@host:5432/name-test

[ravinggenius]

Is there any interest in this? It would be a huge quality of life improvement for any app that needs to run external (non-Next) commands with the environment variables fully resolved according to the rules Next uses. For instance:

• Database migrations that provide a CLI that looks for DATABASE_URL. Instead of having to find the correct URL and pasting it into the terminal (DATABASE_URL=postgres://username:password@host:5432/db-name db-migrate), we could instead run next-env db-migrate
• I have a database seed command that also needs DATABASE_URL. I had to write a custom wrapper to load the correct environment before importing and running the actual command.
• I recently started messing with the i18next-cli, which requires a config file (i18next.config.ts). This config files loads shared i18n config, which in turn loads my env config. My env config is verified with zod, and this verification fails because the expected environment variables aren't loaded. If I was able to run next-env npx i18next-cli, the expected environment variables would be set.

I'm quite happy to write the CLI script and submit it as a merge request.