Environment variables can't be used in config files

[Jutanium]

What kind of changes does this PR include?

• New or updated content

Description

We closed #785 as the corresponding feature was closed, but the note about Astro being unable to load env variables is still important information, even if we don't have a workaround. This PR restores that note and adds a corresponding one to the environmental variables change.

I could see us only wanting one of those two messages, or rather wanting this to be in Troubleshooting. Let me know!

@natemoo-re, if there's currently a workaround to access env variables in Astro, let me know.

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[delucis]

You can access environment variables using process.env in the config file, with the caveat that .env files are NOT loaded yet. An environment variable set by a CI service or on the CLI will be accessible though. For example, you could use process.env.NETLIFY to toggle a feature only in Netlify builds or use TOKEN=secrets npm run dev to expose process.env.TOKEN.

I think I've also heard people are using dotenv to load their .env files, so that could be a workaround if it doesn't have drawbacks — Nate would know best!

[Jutanium]

@delucis Would import.meta.env.NETLIFY work in a config file? (I guess I could deploy to Netlify and see for myself!)

[delucis]

No, import.meta.env is a Vite thing and the config is evaluated in a standard Node environment before Vite is running.

[Jutanium]

Added a section on setting variables with the CLI.

I moved the caution in Environment Variables to the overview. It really is an overview, not an introduction, and import.meta.env is already brought up by that point.

I wasn't sure whether to document process.env in Environment Variables or Configuring Astro. I chose the later because Configuring Astro seems to want to be comprehensive, but I could see other possibilities:

• I could do the opposite where I just have a section in Environment Variables that has all the info, and don't change Configuring Astro.
• Or I could have a caution in Configuring Astro that links to Environment Variables, where the info actually lies.

[delucis]

I think these are good additions, Dan — thank you!

It’s tricky deciding where to document process.env but I think I agree with where you ended up — the most common use case is in the astro config file so makes sense to document it there.

I could leave a bunch more comments on the rest of the environment variables page but I’ll hold off until you say that would be helpful.

[delucis]

More comments as requested by @Jutanium (to be added to this PR or tackled later at his discretion).

1. Opening paragraph:

   Astro uses Vite for environment variables

   I’d probably rewrite to something like

   Astro relies on Vite’s built-in environment variable support

   Or even rewrite the whole opening sentence:

   Astro lets you use any of Vite’s methods to get and set environment variables.

2. “Default environment variables” section

   Totally a nit but in the first list item I’d write either “development | production” or “development or production” but not use the | outside of <code>.

3. “Supported file names” code snippet

   Could probably considered a nit, but might reformat as a table or list. At first glance I read it as a continuation of the .env file example above it.

4. “Getting environment variables” section

   The browser support tip seems excessively noisy in this context. I’d roll that content into the opening paragraph.

[Jutanium]

Thanks @delucis! This page could use a broader reworking (including explaining what Environment Variables actually are), but I made minimal changes for now to address your points.

I removed the .env files snippet entirely as it was copy-pasted from Vite docs - I linked to that instead. I also removed the the tip rather than moving it, as we made this point clear as soon as we talked about client-side code in the intro.

[delucis]

Thanks Dan! LGTM 🙌