RFC: Gatsby serve support for https

[jsloyer]

Summary

This was initially opened under a feature request #38529. The idea is to add https support to the gatsby serve command that exists in the gatsby develop command

Try it out

I would like to add the following parameters to the gatsby serve command, these are copied exactly from the gatsby develop command.

  -S, --https                 Use HTTPS. See https://www.gatsbyjs.com/docs/local-https/ as a guide                                                                                   [boolean]
  -c, --cert-file             Custom HTTPS cert file (also required: --https, --key-file). See https://www.gatsbyjs.com/docs/local-https/                               [string] [default: ""]
  -k, --key-file              Custom HTTPS key file (also required: --https, --cert-file). See https://www.gatsbyjs.com/docs/local-https/                               [string] [default: ""]
  --ca-file                   Custom HTTPS CA certificate file (also required: --https, --cert-file, --key-file).  See https://www.gatsbyjs.com/docs/local-https/       [string] [default: ""]

CodeSandbox

TBD, waiting on approval of this before submitting a branch that does this.

Basic example

N/A

Motivation

Cloud and Kubernetes. Running Gatsby through the netlify cloud and a couple other provides is pretty well integrated, actually seamless. The problem is when you stray outside of that it's pretty hard to get the full functionality of SSR/DSG with Gatsby in the Kubernetes/Docker environment. There has been a couple attempts of writing plugins for this however they are outdated and are not maintained. The [Gatsby docs themselves] (https://www.gatsbyjs.com/docs/reference/rendering-options/deferred-static-generation/)

Note: This feature requires running NodeJS server. It is currently fully supported with [gatsby serve](https://www.gatsbyjs.com/docs/reference/gatsby-cli/#serve) and in [Gatsby Cloud](https://www.gatsbyjs.com/products/cloud/).

mention that DSG is fully supported in the gatsby serve command and in the Gatsby cloud. That isn't quite the case as industry compliances require running ssl from the edge to the application. There are two plugins that expose Gatsby through express but they are way outdated and not maintained.

1. https://github.com/wille/gatsby-plugin-express
2. https://github.com/syfxlin/gatsby-plugin-express

Detailed design

Copying the implementation from gatsby serve to gatsby develop for taking in https certificate info.

Drawbacks

The only thing that I can think of is I remember seeing in the docs somewhere it said not to use gatsby serve in production but there is an occurrence under the DSG docs that mentions to use gatsby serve to get DSG.

Alternatives

The plugins are way out of the date and mostly need to be rewritten top to bottom to update to the latest version of Gatsby.

Adoption strategy

No code mods are needed, this is just a documentation update.

How we teach this

This is pretty easy as well as just updating documentation.

Unresolved questions

N/A