ci(gh-actions): Allow workflow callers to specify the runner as workflow input

Author: PetarKirov

.github/workflows/ci.yml

@@ -4,6 +4,11 @@ on:
   # Allow this workflow to be reused by other workflows:
   workflow_call:
     inputs:
+      runner:
+        description: 'JSON-encoded list of runner labels'
+        default: '["self-hosted"]'
+        required: false
+        type: string
       do_deploy:
         description: 'Deploy to cachix'
         type: 'boolean'
@@ -45,7 +50,7 @@ concurrency:
 
 jobs:
   post-initial-comment:
-    runs-on: self-hosted
+    runs-on: ${{ fromJSON(inputs.runner) }}
     steps:
       - name: 'Post initial package status comment'
         uses: marocchino/[email protected]
@@ -58,7 +63,7 @@ jobs:
 
   generate-matrix-matrix:
     name: Generate Matrix of Matrices
-    runs-on: self-hosted
+    runs-on: ${{ fromJSON(inputs.runner) }}
     steps:
       - name: Install Nix
         uses: metacraft-labs/nixos-modules/.github/install-nix@main
@@ -83,7 +88,7 @@ jobs:
 
   generate-matrix:
     needs: generate-matrix-matrix
-    runs-on: self-hosted
+    runs-on: ${{ fromJSON(inputs.runner) }}
     strategy:
       matrix: ${{fromJSON(needs.generate-matrix-matrix.outputs.gen_matrix)}}
     name: Generate Matrix ${{ matrix.digit != -1 && matrix.digit || '' }}
@@ -119,7 +124,7 @@ jobs:
       matrix: ${{ steps.generate-matrix.outputs.matrix }}
 
   slurp-matrix:
-    runs-on: self-hosted
+    runs-on: ${{ fromJSON(inputs.runner) }}
     needs: generate-matrix
     name: Merge matrices
     outputs:
@@ -207,7 +212,7 @@ jobs:
           cachix push ${{ vars.CACHIX_CACHE }} ${{ matrix.output }}
 
   results:
-    runs-on: self-hosted
+    runs-on: ${{ fromJSON(inputs.runner) }}
     name: Final Results
     needs: [build, slurp-matrix]
     if: always()

.github/workflows/update-flake-lock.yml

@@ -3,6 +3,13 @@ name: "Update Nix Flake lockfile"
 on:
   # Allow this workflow to be reused by other workflows:
   workflow_call:
+    inputs:
+      runner:
+        description: 'JSON-encoded list of runner labels'
+        default: '["self-hosted"]'
+        required: true
+        type: string
+
     secrets:
       NIX_GITHUB_TOKEN:
         description: GitHub token to add as access-token in nix.conf
@@ -26,7 +33,7 @@ on:
 
 jobs:
   main:
-    runs-on: self-hosted
+    runs-on: ${{ fromJSON(inputs.runner) }}
 
     steps:
       - uses: actions/checkout@v4

.github/workflows/update-flake-packages.yml

@@ -3,6 +3,13 @@ name: "Update Flake Packages ❄️"
 on:
   # Allow this workflow to be reused by other workflows:
   workflow_call:
+    inputs:
+      runner:
+        description: 'JSON-encoded list of runner labels'
+        default: '["self-hosted"]'
+        required: true
+        type: string
+
     secrets:
       NIX_GITHUB_TOKEN:
         description: GitHub token to add as access-token in nix.conf
@@ -26,7 +33,7 @@ on:
 
 jobs:
   updateFlakePackages:
-    runs-on: self-hosted
+    runs-on: ${{ fromJSON(inputs.runner) }}
     steps:
       - name: Checkout repository
         uses: actions/checkout@v4