[Bug]: Predefined environment variables not passed to Nixpacks

[sillvva]

Description

I pushed a PR to test predefined environment variables to a preview deployment on my Sveltekit app. The environment variables are being passed to Nixpacks as literal strings rather than being replaced with the predefined values.

I followed the instructions here: https://coolify.io/docs/knowledge-base/environment-variables

Minimal Reproduction (if possible, example repository)

Example variables:

TEST_URL=$COOLIFY_URL
PUBLIC_TEST_URL=$COOLIFY_URL

Build variable is checked. Is Literal? is not checked.

Exception or Error

The resulting Final Nixpacks plan looks like this:

Final Nixpacks plan: {
"providers": [],
"buildImage": "ghcr.io\/railwayapp\/nixpacks:ubuntu-1716249803",
"variables": {
"SOURCE_COMMIT": "8887ff2d43fa705c29557d55a2320a50b95f36eb",
...HIDDEN_REAL_VARIABLES...
"PUBLIC_TEST_URL": "$COOLIFY_URL",
"TEST_URL": "$COOLIFY_URL",
"CI": "true",
"NIXPACKS_METADATA": "node",
"NODE_ENV": "production",
"NPM_CONFIG_PRODUCTION": "false"
},

And the resulting environment variables look like this with console.table:

#14 13.85 Coolify check: process.env
#14 13.85
#14 13.85 ┌─────────────────┬────────────────┐
#14 13.85 │ (index) │ Values │
#14 13.85 ├─────────────────┼────────────────┤
#14 13.85 │ PUBLIC_TEST_URL │ '$COOLIFY_URL' │
#14 13.85 │ TEST_URL │ '$COOLIFY_URL' │
#14 13.85 └─────────────────┴────────────────┘

Version

v4.0.0-beta.297

[Aunali321]

i thought i was going crazy

[jacobschwantes]

Also facing this issue. The environment variable is getting set correctly in the container but $coolify_url is what gets passed if its marked as a build variable.

[lorenzomigliorero]

Probably related to #2316

[seloElo]

Still have the issue today on last beta

[jycouet]

I think that this is fixed (I'm on v4.0.0-beta.373)

[peaklabs-dev]

This issue should be resolved in the latest version. If you're still experiencing this issue, please reopen or create a new issue with updated details.

[sillvva]

I am still having this issue on 4.0.0-beta.373

Example environment variable (build variable checked, literal not checked):

PUBLIC_TEST_URL=$COOLIFY_URL

In the "Final Nixpacks Plan"

"PUBLIC_TEST_URL": "$COOLIFY_URL",

Logged output during build:

#14 14.79 │ PUBLIC_TEST_URL       │ '$COOLIFY_URL'

For the record, the above is a test variable on a SvelteKit app. During the build, I call a console.table after parsing the environment variables with a schema library.

[99Arrzel]

Is there any workaround for this at the moment?
This is annoying for PR deployments lol

[BedroomDev]

still doesnt work on 4.0.0-beta.380 newest version to date

• UndefinedVar: Usage of undefined variable '$NIXPACKS_PATH' (line 18)
  2025-Jan-15 14:55:41.022784

[sillvva]

I think I saw a potential fix coming in 381. It's not released yet.

I noticed it at about 0:04 on the video
https://bsky.app/profile/heyandras.dev/post/3lfp73cifx62e

[viktorkuts]

I think I saw a potential fix coming in 381. It's not released yet.

I noticed it at about 0:04 on the video https://bsky.app/profile/heyandras.dev/post/3lfp73cifx62e

Nope, I tried 381 and even 382 and that didn't fix any issues, still ongoing

[viktorkuts]

Adding to this, it seems as if it is only limited to static pages, like using Vite, Svelte etc.
Whenever I dump the process env in my frontend (Vite & React) static build, I get no COOLIFY_ or they stay literals as $COOLIFY_
However in my backend (Java Spring Boot), the env dump has all the predefined variables, without even needing to bind them to a project variable.

One thing to note however, when I dump the envs in the terminal of the frontend in coolify, I do see the predefined variables, which is more how the backend deployment behaves. It's very strange behavior.