CLI : add option to specify the output mode to next build

[alaindeurveilher]

Goals

1. It would be nice to have a flexible way to choose how to build the application, either in standalone mode or not
2. an option to "next build" cli could be a possible solution to either specify the output (and/or override it), or to specify a different config file than the default next.config.js
3. One project could have different deployment strategy to different environment. For example: deciding to deploy in standalone on my own computer or in container on my PC, but deploy in standard mode (undefined) in Openshift or whatever for some other purpose

Non-Goals

Background

I have currently a need to deploy an instance of my app on my laptop for localhost usage, and share this installation/deployment strategy with some colleagues in my team.
"standalone" output seems convenient, as I can have it built once, and deployed for pm2. Then anyone can run the app through pm2 without opening the development environment.

But I would like it to be deployed on some server in OpenShift using the standard default output too for some other purpose

Proposal

See Goals section for the proposal

Example:

• next build --output standalone
• next build --config-file next.config.standalone.js

[alaindeurveilher]

Just a remark, I just noticed a way to perform this with the following, using environment variables:

next.config.js

/** @type {import('next').NextConfig} */

const BUILD_OUTPUT = process.env.NEXT_CONFIG_BUILD_OUTPUT === 'standalone' ? 'standalone' : undefined;

const nextConfig = {
  output: BUILD_OUTPUT,
  // ...
};

module.exports = nextConfig;