ci: rework into using a job matrix

.forgejo/workflows/ci.yml

@@ -6,16 +6,58 @@ on:
     branches: [main]
 
 jobs:
-  nixos-x86_64-linux:
+  get-x86_64-hosts:
     runs-on: self-hosted-x86_64-linux
+    outputs:
+      hosts: ${{ steps.output-hosts.outputs.hosts }}
     steps:
       - uses: actions/checkout@v3
-      - run: ./.ci.sh
-      # - run: ./.ci.sdImages.sh
+      - name: output-hosts
+        run: |
+          HOSTS_JSON="$(nix eval -I nixpkgs=$(nix flake metadata nixpkgs --json | jq -r .path) --raw --impure --expr '
+            with import <nixpkgs> { };
+            builtins.toJSON (lib.mapAttrsToList (n: v: n)
+              (lib.attrsets.filterAttrs (n: v: v.pkgs.system == pkgs.system)
+                (builtins.getFlake(builtins.toString ./.)).outputs.nixosConfigurations))'
+          )"
+          echo "::set-output name=hosts::${HOSTS_JSON}"
 
-  nixos-aarch64-linux:
+  get-aarch64-hosts:
     runs-on: self-hosted-aarch64-linux
+    outputs:
+      hosts: ${{ steps.output-hosts.outputs.hosts }}
     steps:
       - uses: actions/checkout@v3
-      - run: ./.ci.sh
-      # - run: ./.ci.sdImages.sh
+      - name: output-hosts
+        run: |
+          HOSTS_JSON="$(nix eval -I nixpkgs=$(nix flake metadata nixpkgs --json | jq -r .path) --raw --impure --expr '
+            with import <nixpkgs> { };
+            builtins.toJSON (lib.mapAttrsToList (n: v: n)
+              (lib.attrsets.filterAttrs (n: v: v.pkgs.system == pkgs.system)
+                (builtins.getFlake(builtins.toString ./.)).outputs.nixosConfigurations))'
+          )"
+          echo "::set-output name=hosts::${HOSTS_JSON}"
+
+  build-nixos-x86_64-linux:
+    runs-on: self-hosted-x86_64-linux
+    needs: get-x86_64-hosts
+    strategy:
+      matrix:
+        host: ${{fromJSON(needs.get-x86_64-hosts.outputs.hosts)}}
+    steps:
+      - uses: actions/checkout@v3
+      - name: build host configuration ${{ matrix.host }}
+        run: |
+          nixos-rebuild build --verbose --flake ".#${{ matrix.host }}"
+
+  build-nixos-aarch64-linux:
+    runs-on: self-hosted-aarch64-linux
+    needs: get-aarch64-hosts
+    strategy:
+      matrix:
+        host: ${{fromJSON(needs.get-aarch64-hosts.outputs.hosts)}}
+    steps:
+      - uses: actions/checkout@v3
+      - name: build host configuration ${{ matrix.host }}
+        run: |
+          nixos-rebuild build --verbose --flake ".#${{ matrix.host }}"