beforeBuildCommand not executed in the correct directory

[gworkman]

First off, thank you for making this! I got started on building a desktop app last week after seeing your talk at ElixirConf EU, and it has been incredibly easy to work with!

We're now at the point where I want to build some binaries and distribute to others for testing. I'm running into some issues when following the docs. The beforeBuildCommand specified in the docs attempts to compile the mix project from the src-tauri directory. I ended up changing it from:

"beforeBuildCommand": "MIX_ENV=prod mix do compile + assets.deploy + release --overwrite --path src-tauri/target/rel"

to:

"beforeBuildCommand": "cd .. && MIX_ENV=prod mix do compile + assets.deploy + release --overwrite --path src-tauri/target/rel"

This gets it to build, but not sure this is the best way to do this/if it interferes with other paths when building binaries or signing releases (haven't got that far yet)

[wojtekmach]

Hey @gworkman, thank you for reporting this and trying out elixirkit!

Were you following tauri guide and ended up in this incorrect state? Does you project layout match https://github.com/livebook-dev/elixirkit/tree/main/examples/tauri_project layout, i.e:

./
  mix.exs
  src-tauri/

? I just did cd examples/tauri_project && cargo tauri build and seems to work well.

[gworkman]

Hey @wojtekmach, the project is identical, as far as I can tell. The top level tree looks like the following:

├── AGENTS.md
├── config
├── lib
├── LICENSES
├── mix.exs
├── mix.lock
├── priv
├── README.md
├── src-tauri
└── test

In src-tauri/tauri.conf.json

{
  "$schema": "https://schema.tauri.app/config/2",
  "productName": "Nerves Desktop",
  "version": "0.1.0",
  "identifier": "org.nerves-project.NervesDesktop",
  "build": {
    "beforeBuildCommand": "cd .. && mix do compile + assets.deploy + release --overwrite --path src-tauri/target/rel"
  },
  "app": {
    "withGlobalTauri": true,
    "security": {
      "csp": null
    }
  },
  "bundle": {
    "active": true,
    "targets": "all",
    "resources": {
      "target/rel": "rel"
    },
    "icon": [
      "icons/128x128.png",
      "icons/128x128@2x.png",
      "icons/32x32.png",
      "icons/icon.icns",
      "icons/icon.ico"
    ]
  }
}

I also just checked, and elixirkit/examples/tauri_project does indeed properly work when I run cargo tauri build in the top level directory

Edit: yes, I was following the tauri guide here, pretty much every step except the code signing.

Edit2: Here's the error message when I remove the cd .. at the front of the build command:

❯ cargo tauri build
        Info Looking up installed tauri packages to check mismatched versions...
     Running beforeBuildCommand `mix do compile + assets.deploy + release --overwrite --path src-tauri/target/rel`
** (Mix) Could not find a Mix.Project, please ensure you are running Mix in a directory with a mix.exs file
       Error beforeBuildCommand `mix do compile + assets.deploy + release --overwrite --path src-tauri/target/rel` failed with exit code 1

[gworkman]

Hi @wojtekmach, thanks for spending some time looking into this issue. I took another look at the issue and found the problem. I would guess this is going to be a common issue, so it might be good to add some info to the docs:

1. Tauri generated a src-tauri/package.json and other js-related files (including a src-tauri/node_modules which I didn't realize - I think it came from the project generator?). From the docs, Tauri seems to be sensitive to a package.json in your project and cargo tauri build will build in the directory where the package.json lives. So initially, it was choosing src-tauri/ for me since there was a package.json there.
2. After removing the src-tauri/package.json, it was picking up my assets/ folder as the project root. This is because I was installing some dependencies with npm. I copied them over to the assets/vendor/ directory and deleted all package.json, node_modules, etc from the assets/ dir and now cargo tauri build is happy :)