ci: migrate to flake-gha

.github/workflows/flake-gha.yml

@@ -0,0 +1,45 @@
+name: "Flake-managed workflow"
+on:
+  pull_request:
+  push:
+jobs:
+  config:
+    runs-on: ubuntu-latest
+    outputs:
+      config: ${{ steps.config.outputs.config }}
+    steps:
+    - uses: actions/checkout@v4
+    - uses: cachix/install-nix-action@v29
+    - id: config
+      name: Get config from the flake
+      run: |
+        printf 'config=' >> "$GITHUB_OUTPUT"
+        nix eval --json .#githubActions.config >> "$GITHUB_OUTPUT"
+  check:
+    needs: config
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v4
+    - uses: cachix/install-nix-action@v29
+    - run: nix flake check --all-systems --no-build
+      if: ${{ fromJSON(needs.config.outputs.config).checkAllSystems }}
+    - run: nix flake check --no-build
+      if: ${{ ! fromJSON(needs.config.outputs.config).checkAllSystems }}
+  build:
+    needs: config
+    strategy:
+      matrix:
+        include: ${{ fromJSON(needs.config.outputs.config).matrix }}
+    runs-on: ${{ matrix.os }}
+    steps:
+    - uses: actions/checkout@v4
+    - uses: cachix/install-nix-action@v29
+    - uses: cachix/cachix-action@v15
+      if: ${{ matrix.enableCachix }}
+      with:
+        name: ${{ fromJSON(needs.config.outputs.config).cacheName }}
+        authToken: ${{ secrets.CACHIX_AUTH_TOKEN }}
+        pathsToPush: ${{ matrix.pathsToPush }}
+        skipPush: ${{ matrix.skipPush }}
+    - run: |
+        nix-build --no-link --keep-going --expr '{ system }: (builtins.getFlake (toString ./.)).githubActions.target.${system}' --argstr system ${{ matrix.double }}

flake.nix

@@ -11,6 +11,8 @@
       nixpkgs.follows = "nixpkgs";
     };
     crane.url = "github:ipetkov/crane";
+    flake-gha.url = "github:thecaralice/flake-gha";
+    flake-gha.inputs.flake-parts.follows = "flake-parts";
   };
   outputs =
     inputs@{
@@ -19,12 +21,14 @@
       flake-parts,
       ez-configs,
       crane,
+      flake-gha,
       ...
     }:
     flake-parts.lib.mkFlake { inherit inputs; } {
       systems = nixpkgs.lib.platforms.all;
       imports = [
         ez-configs.flakeModule
+        flake-gha.flakeModule
       ];
       ezConfigs.root = ./.;
       ezConfigs.earlyModuleArgs = {
@@ -43,6 +47,11 @@
           packages.server = pkgs.callPackage ./packages/server { inherit craneLib; };
           packages.frontends = pkgs.callPackage ./packages/frontends { };
         };
+      githubActions = {
+        cachix.enable = true;
+        cachix.cacheName = "trieve";
+        checkAllSystems = false;
+      };
     };
   nixConfig = {
     substituters = [ "https://trieve.cachix.org" ];