chore: Delete cache-build cache entries on PR close (#26312)

* chore: Delete cache-build cache entries on PR close

Co-Authored-By: keith@cal.com <keithwillcode@gmail.com>

* refactor: Extract cache-build key generation into reusable action

- Create .github/actions/cache-build-key to generate cache keys
- Update cache-build action to use the shared key action
- Update delete workflow to use the shared key action
- Checkout PR head SHA in delete workflow for correct hash computation

Co-Authored-By: keith@cal.com <keithwillcode@gmail.com>

* fix: Remove PR head SHA checkout per review feedback

Co-Authored-By: keith@cal.com <keithwillcode@gmail.com>

* refactor: Use prefix-based cache deletion for simpler cleanup

- Use useblacksmith/cache-delete prefix mode to delete all caches matching branch
- Remove dependency on cache-build-key action for deletion
- No checkout needed since we're just using the branch name as prefix

Co-Authored-By: keith@cal.com <keithwillcode@gmail.com>

* refactor: Simplify cache key by removing Linux and node version segments

Co-Authored-By: keith@cal.com <keithwillcode@gmail.com>

---------

Co-authored-by: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>

.github/actions/cache-build-key/action.yml

@@ -0,0 +1,23 @@
+name: Generate cache-build key
+description: "Generate the cache key for production build caching"
+inputs:
+  branch_key:
+    required: true
+    description: "Branch key for cache scoping (e.g., github.head_ref for PRs)"
+outputs:
+  key:
+    description: "The generated cache key"
+    value: ${{ steps.generate-key.outputs.key }}
+runs:
+  using: "composite"
+  steps:
+    - name: Generate cache key
+      id: generate-key
+      shell: bash
+      env:
+        CACHE_NAME: prod-build
+        BRANCH_KEY: ${{ inputs.branch_key }}
+        LOCKFILE_HASH: ${{ hashFiles('yarn.lock') }}
+        SOURCE_HASH: ${{ hashFiles('apps/**/**.[jt]s', 'apps/**/**.[jt]sx', 'apps/**/*.json', 'apps/**/*.css', 'packages/**/**.[jt]s', 'packages/**/**.[jt]sx', 'packages/prisma/schema.prisma', 'packages/prisma/migrations/**/*.sql', '!**/node_modules/**', '!packages/prisma/generated/**', '!packages/prisma/client/**', '!packages/prisma/zod/**', '!packages/kysely/**') }}
+      run: |
+        echo "key=${CACHE_NAME}-${BRANCH_KEY}-${LOCKFILE_HASH}-${SOURCE_HASH}" >> $GITHUB_OUTPUT

.github/actions/cache-build/action.yml

@@ -1,31 +1,23 @@
 name: Cache production build binaries
 description: "Cache or restore if necessary"
-inputs:
-  node_version:
-    required: false
-    default: v18.x
 runs:
   using: "composite"
   steps:
+    - name: Generate cache key
+      id: cache-key
+      uses: ./.github/actions/cache-build-key
+      with:
+        branch_key: ${{ github.head_ref || github.ref_name }}
     - name: Cache production build
       uses: actions/cache@v4
       id: cache-build
-      env:
-        cache-name: prod-build
-        # Use branch name for cache scoping (head_ref for PRs, ref_name for pushes)
-        branch-key: ${{ github.head_ref || github.ref_name }}
-        # Hash yarn.lock for dependency changes
-        lockfile-hash: ${{ hashFiles('yarn.lock') }}
-        # Hash source files that affect the web build, excluding generated directories
-        # Excludes packages/prisma/{generated,client,zod}/* and packages/kysely/* which are generated by prisma generate
-        source-hash: ${{ hashFiles('apps/**/**.[jt]s', 'apps/**/**.[jt]sx', 'apps/**/*.json', 'apps/**/*.css', 'packages/**/**.[jt]s', 'packages/**/**.[jt]sx', 'packages/prisma/schema.prisma', 'packages/prisma/migrations/**/*.sql', '!**/node_modules/**', '!packages/prisma/generated/**', '!packages/prisma/client/**', '!packages/prisma/zod/**', '!packages/kysely/**') }}
       with:
         path: |
           ${{ github.workspace }}/apps/web/.next
           ${{ github.workspace }}/apps/web/public/embed
           **/.turbo/**
           **/dist/**
-        key: ${{ runner.os }}-${{ env.cache-name }}-${{ inputs.node_version }}-${{ env.branch-key }}-${{ env.lockfile-hash }}-${{ env.source-hash }}
+        key: ${{ steps.cache-key.outputs.key }}
     - run: |
         export NODE_OPTIONS="--max_old_space_size=8192"
         yarn build

.github/workflows/delete-blacksmith-cache.yml

@@ -1,4 +1,4 @@
-name: Manually Delete Blacksmith Cache
+name: Delete Blacksmith Cache
 on:
   workflow_dispatch:
     inputs:
@@ -6,12 +6,28 @@ on:
         description: "Blacksmith Cache Key to Delete"
         required: true
         type: string
+  pull_request:
+    types: [closed]
+
 jobs:
   manually-delete-blacksmith-cache:
+    if: github.event_name == 'workflow_dispatch'
     runs-on: blacksmith-2vcpu-ubuntu-2404
     steps:
       - name: Checkout
         uses: actions/checkout@v4
       - uses: useblacksmith/cache-delete@v1
         with:
-          cache_key: ${{ inputs.cache_key }}
+          key: ${{ inputs.cache_key }}
+
+  delete-cache-build-on-pr-close:
+    if: github.event_name == 'pull_request' && github.event.action == 'closed'
+    runs-on: blacksmith-2vcpu-ubuntu-2404
+    env:
+      CACHE_NAME: prod-build
+    steps:
+      - name: Delete cache-build cache
+        uses: useblacksmith/cache-delete@v1
+        with:
+          key: ${{ env.CACHE_NAME }}-${{ github.event.pull_request.head.ref }}
+          prefix: "true"