KAFKA-17542: Automatically label small PRs (#17260)

Reviewers: Chia-Ping Tsai <chia7712@gmail.com>, David Arthur <mumrah@gmail.com>

.github/scripts/label_small.sh

@@ -0,0 +1,30 @@
+#!/bin/bash
+# Licensed to the Apache Software Foundation (ASF) under one or more
+# contributor license agreements.  See the NOTICE file distributed with
+# this work for additional information regarding copyright ownership.
+# The ASF licenses this file to You under the Apache License, Version 2.0
+# (the "License"); you may not use this file except in compliance with
+# the License.  You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+LABEL_NAME=small
+MAX_SIZE=100
+
+pr_diff=$(gh pr diff $PR_NUM -R $GITHUB_REPOSITORY)
+
+insertions=$(printf "$pr_diff" | grep '^+' | wc -l)
+deletions=$(printf "$pr_diff" | grep '^-' | wc -l)
+
+total_changes=$((insertions + deletions))
+if [ "$total_changes" -lt "$MAX_SIZE" ]; then
+    gh issue edit $PR_NUM --add-label $LABEL_NAME -R $GITHUB_REPOSITORY
+else
+    gh issue edit $PR_NUM --remove-label $LABEL_NAME -R $GITHUB_REPOSITORY
+fi

.github/workflows/labeler.yml

@@ -18,7 +18,6 @@ on:
   pull_request_target:
     types: [opened, reopened, synchronize]
 
-
 jobs:
   label_PRs:
     permissions:
@@ -26,6 +25,14 @@ jobs:
       pull-requests: write
     runs-on: ubuntu-latest
     steps:
+    - name: Checkout code
+      uses: actions/checkout@v4
     - uses: actions/labeler@v5
       with:
         configuration-path: .github/configs/labeler.yml
+    - name: check small label
+      env:
+        GH_TOKEN: ${{ github.token }}
+        PR_NUM: ${{github.event.number}}
+      run: |
+        ./.github/scripts/label_small.sh