Issue building multi-arch platform images

[gabemeola]

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

Nixpacks isn't building as expected when using multiple platforms.

$ nixpacks build . --platform linux/amd64,linux/arm64


╔════════ Nixpacks v1.19.0 ═══════╗
║ setup      │ nodejs_18, npm-8_x ║
║─────────────────────────────────║
║ install    │ npm ci             ║
║─────────────────────────────────║
║ build      │ npm run build      ║
║─────────────────────────────────║
║ start      │ npm run start      ║
╚═════════════════════════════════╝

[+] Building 0.0s (0/0)                                                                             docker:desktop-linux
ERROR: Multiple platforms feature is currently not supported for docker driver. Please switch to a different driver (eg. "docker buildx create --use")
Error: Docker build failed

To reproduce

1. Create project e.g. npx create-next-app@latest
2. Start docker
3. Build project with nixpacks & some platforms: nixpacks build . --platform linux/amd64,linux/arm64

Expected behavior

Should use docker buildx to build images. Would need to be pushed as well.

Environment

• nixpacks 1.19.0
• MacOS

[github-actions]

Hello, @gabemeola! Thanks for your submission.

Our team will respond soon. If you need more immediate help, try our Forum or our Discord. Thanks!

[gabemeola]

Looks like loading into a docker image locally is not available but could still be pushed.
docker/buildx#59

[gabemeola]

A workaround I've found is dumping the Dockerfile and running it manually.

nixpacks build . -o . && docker buildx build --platform linux/amd64,linux/arm64 -f ./.nixpacks/Dockerfile .

[zuchka]

@gabemeola how do you feel about the state of this issue? Should we add this to the nixpacks docs?

[gabemeola]

@zuchka Hm if --platform is intended to be available on Mac and Windows, nixpacks could call buildx under the hood instead of build. What do you think?

The workaround isn't 100% accurate since build args are not present.

[sanmai-NL]

--platform works on non-Linux, yes.

[iloveitaly]

Would be great to at least add this to the docs, in my view.