Run linkcheck on changed files only on PRs (#2111)

* Run linkcheck on changed files only on PRs

* Fix job setup

* Update Makefile

Author: TheTripleV

.github/workflows/CI.yml

@@ -83,21 +83,37 @@ jobs:
       run: |
         sphinx-build -D language=es -b html . _build/html
 
-  check-links:
+  link-check-diff:
+    # This job is sourced from https://github.com/aiven/devportal/blob/main/.github/workflows/linkcheck-changed-files.yaml
+    # It is CC 4.0 I licensed: https://creativecommons.org/licenses/by/4.0/
+    # Changes have been made.
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v3
-      with:
-        fetch-depth: 0
-    - uses: actions/setup-python@v4
-      with:
-        python-version: 3.9
-    - name: Install Dependencies
-      run: |
-        pip install -r source/requirements.txt
-    - name: Check Links
-      run: |
-        make linkcheck
+      - uses: actions/checkout@v3
+        with:
+          fetch-depth: 0
+      - name: Get changed files
+        id: changed-files
+        uses: tj-actions/changed-files@v24
+      - uses: actions/setup-python@v4
+        with:
+          python-version: 3.9
+      - name: Install Dependencies
+        run: pip install -r source/requirements.txt
+      - name: Run linkcheck on .rst files
+        run: |
+          for file in ${{ steps.changed-files.outputs.all_changed_files }}; do
+            if [ "${file: -4}" == ".rst" ]
+              then
+                var="$var $file"
+            fi
+          done
+          if [ -z "$var" ]
+          then
+                echo "No *.rst changed files to check."
+          else
+                make BUILDER_ARGS="$var" linkcheck
+          fi
         
   check-linting:
     runs-on: ubuntu-latest

Makefile

@@ -11,6 +11,7 @@ LINTEROPTS    = --ignore D001 # D001 is linelength
 SIZECHECKER   = python3 -m scripts.imagesizechecker
 CONFEXCLUDE   = --exclude-file source/conf.py
 SIZEMAX       = 500
+BUILDER_ARGS   ?=
 
 ifeq ($(CI), true)
 	SPHINXOPTS += --color
@@ -31,4 +32,4 @@ sizecheck:
 # Catch-all target: route all unknown targets to Sphinx using the new
 # "make mode" option.  $(O) is meant as a shortcut for $(SPHINXOPTS).
 %: Makefile
-	@$(SPHINXBUILD) -M $@ "$(SOURCEDIR)" "$(BUILDDIR)" $(SPHINXOPTS) $(O)
+	@$(SPHINXBUILD) -M $@ "$(SOURCEDIR)" "$(BUILDDIR)" $(BUILDER_ARGS) $(SPHINXOPTS) $(O)