Adds check for oss license in source files (#4)

.github/workflows/ci.yaml

@@ -17,3 +17,7 @@ jobs:
       - name: Component tests for Bash Linter
         uses: ./checks/bash
 
+      - name: Component tests for license enforcer
+        uses: ./checks/licenses
+        with:
+          file-patterns: "*.sh"

checks/licenses/action.yaml

@@ -0,0 +1,19 @@
+name: "Lint documentation and find typos"
+description: "Standardize documentation and prose with different linters"
+
+inputs:
+  file-patterns:
+    description: “Patterns to look in source files, comma separated”
+    required: true
+
+  license:
+    description: “Open-source license to enforce”
+    default: "mit"
+    required: true
+
+runs:
+  using: "composite"
+  steps:
+      - name: Check licenses on source files
+        shell: bash
+        run: ./src/license-enforcer.sh $GITHUB_WORKSPACE ${{ inputs.file-patterns }} ${{ inputs.license }}

src/license-enforcer.sh

@@ -0,0 +1,59 @@
+#!/usr/bin/env bash
+# Copyright 2023 Dotanuki Labs
+# SPDX-License-Identifier: MIT
+
+# shellcheck disable=SC2046
+
+set -eo pipefail
+
+# https://github.com/google/addlicense
+readonly image="ghcr.io/google/addlicense"
+
+readonly target_folder="$1"
+readonly sources="$2"
+readonly license="$3"
+
+require_docker() {
+    if (! docker stats --no-stream >/dev/null); then
+        echo "Docker is required for this check"
+        echo
+        exit 1
+    fi
+}
+
+check_license_on_files() {
+    local extension="$1"
+
+    echo "→ Checking licenses for $files files"
+
+    docker run --rm -v "${target_folder}:/src" "$image" \
+        -c "Dotanuki Labs" \
+        -l "$license" \
+        -check $(find . -type f -name "$extension")
+}
+
+report_missing_licenses() {
+    echo
+    echo "There are files with missing ($license) license"
+    echo
+    exit 1
+}
+
+enforce_license_for_file_patterns() {
+    IFS=" " read -r -a files <<<"$(echo "$sources" | sed "s/,/[:space:]/g" | xargs)"
+
+    for type in "${files[@]}"; do
+        check_license_on_files "$type" || report_missing_licenses
+    done
+}
+
+echo
+echo "🔥 Enforcing open-source license on source files"
+echo
+
+require_docker
+enforce_license_for_file_patterns
+
+echo
+echo "✅ All good!"
+echo