add license headers check github workflow

Author: Mpdreamz

.github/add-license-headers.sh

@@ -0,0 +1,14 @@
+#!/bin/bash
+script_path=$(dirname $(realpath $0))/../
+
+function add_license () {
+    (find "$script_path" -name $1 | grep -v "/bin/" | grep -v "/obj/" )|while read fname; do
+        line=$(sed -n '2p;3q' "$fname")
+        if ! [[ "$line" == " * Licensed to Elasticsearch B.V. under one or more contributor" ]] ; then
+            cat "${script_path}.github/license-header.txt" "$fname" > "${fname}.new"
+            mv "${fname}.new" "$fname"
+        fi
+    done
+}
+
+add_license "*.cs"

.github/workflows/license.yml

@@ -0,0 +1,18 @@
+name: License headers
+
+on: [ pull_request ]
+
+permissions:
+  contents: read
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Check license headers
+        run: |
+          ./.github/check-license-headers.sh