Prepare uml diagram generation during Jekyll build

.github/workflows/pages.yml

@@ -22,6 +22,10 @@ concurrency:
   group: "pages"
   cancel-in-progress: true
 
+defaults:
+  run:
+    shell: bash
+
 jobs:
   # Build job
   build:
@@ -31,6 +35,22 @@ jobs:
         uses: actions/checkout@v3
       - name: Setup Pages
         uses: actions/configure-pages@v2
+
+      - name: Count number of plantuml files
+        id: count-plantuml
+        run: |
+          count=$(find docs/ -name \*.puml | wc -l)
+          echo "There are $count plantuml files"
+          echo "::set-output name=num::$count"
+      - name: Install PlantUML on demand
+        if: steps.count-plantuml.outputs.num > 0
+        run: |
+          sudo apt-get update
+          sudo apt-get install --no-install-recommends -y plantuml
+      - name: Build PlantUML images
+        if: steps.count-plantuml.outputs.num > 0
+        run: make -C docs build-uml-svg
+
       - name: Build with Jekyll
         uses: actions/jekyll-build-pages@v1
         with:

docs/Makefile

@@ -2,10 +2,13 @@
 BUNDLER=bundler
 HOST=127.0.0.1
 
+PLANTUML_SRC=$(shell find -name \*.puml ! -path ./_site/\*)
+PLANTUML_DST_SVG=${PLANTUML_SRC:%.puml=%.svg}
+
 .PHONY: all
 all: help
 
-.PHONY: help watch build install
+.PHONY: help watch build install build-uml-svg
 
 help:
 	@echo "Make tragets supported:"
@@ -23,3 +26,15 @@ watch:
 install:
 	${BUNDLER} install
 
+build-uml-svg:
+ifeq ($(strip ${PLANTUML_SRC}),)
+	@echo 'No plantuml files were found. Skipping.'
+else
+	${MAKE} ${PLANTUML_DST_SVG}
+endif
+
+%.svg: %.puml
+	plantuml -tsvg $<
+
+%.png: %.puml
+	plantuml -tpng $<