Add auto label creation step in release draft workflow

.github/workflows/generate-release-draft.yml

@@ -1,8 +1,7 @@
-name: Release Drafter
+name: Generate release draft and label PRs
 
 on:
   push:
-    # branches to consider in the event; optional, defaults to all
     branches:
       - main
 
@@ -29,10 +28,71 @@ jobs:
       pull-requests: write
     runs-on: ubuntu-latest
     steps:
-      # (Optional) GitHub Enterprise requires GHE_HOST variable set
-      #- name: Set GHE_HOST
-      #  run: |
-      #    echo "GHE_HOST=${GITHUB_SERVER_URL##https:\/\/}" >> $GITHUB_ENV
+      - name: Checkout code
+        uses: actions/checkout@v4
+
+      # Setup Node.js environment
+      - uses: actions/setup-node@v4
+        with:
+          node-version: "20.x"
+      - run: npm install js-yaml
+
+      # ラベルが存在しなければ作成
+      - name: Ensure autolabeler labels exist
+        uses: actions/github-script@v7
+        with:
+          github-token: ${{ secrets.GITHUB_TOKEN }}
+          script: |
+            const fs = require('fs');
+            const yaml = require('js-yaml');
+
+            const configPath = '.github/release-drafter.yml';
+            const content = fs.readFileSync(configPath, 'utf8');
+            const config = yaml.load(content);
+
+            const DEFAULT_COLOR = 'ededed';  // 色は最後で指定
+
+            // 既存ラベル一覧を取得
+            const existingLabelsResponse = await github.rest.issues.listLabelsForRepo({
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              per_page: 100,
+            });
+            const existingLabels = new Set(existingLabelsResponse.data.map(label => label.name));
+
+            // autolabeler + exclude-labels のラベルをセットで保持（重複防止）
+            const labelsToEnsure = new Set();
+
+            // autolabelerのラベル追加
+            if (Array.isArray(config.autolabeler)) {
+              for (const rule of config.autolabeler) {
+                if (rule.label) {
+                  labelsToEnsure.add(rule.label);
+                }
+              }
+            }
+
+            // exclude-labelsのラベル追加
+            if (Array.isArray(config['exclude-labels'])) {
+              for (const label of config['exclude-labels']) {
+                labelsToEnsure.add(label);
+              }
+            }
+
+            // ラベル作成処理
+            for (const label of labelsToEnsure) {
+              if (!existingLabels.has(label)) {
+                console.log(`Creating label: ${label} with color ${DEFAULT_COLOR}`);
+                await github.rest.issues.createLabel({
+                  owner: context.repo.owner,
+                  repo: context.repo.repo,
+                  name: label,
+                  color: DEFAULT_COLOR,
+                });
+              } else {
+                console.log(`Label already exists: ${label}`);
+              }
+            }
 
       # Drafts your next Release notes as Pull Requests are merged into "master"
       - uses: release-drafter/release-drafter@v6