Rework image generation workflow

.github/actions/lint-asciidoc/action.yml

@@ -0,0 +1,69 @@
+name: Lint AsciiDoc
+
+runs:
+  using: "composite"
+  steps:
+    - name: Verify image references
+      shell: bash
+      run: |
+        function err {
+          >&2 echo -e "\033[0;31m$@\033[0m"
+        }
+
+        rc=0
+
+        while read -r file; do
+          echo "Checking $file"
+
+          root=$(grep "^:imagesdir:" "$file" | sed -E "s/^:imagesdir:[[:space:]]*//")
+          if [[ ! -z "$root" ]]; then
+            if [[ "$root" == /* ]]; then
+              root=$(git rev-parse --show-toplevel)$root
+            fi
+            if [[ ! "$root" == */ ]]; then
+              root=$root/
+            fi
+          fi
+          echo "Found imagedir ${root:-<null>}"
+
+          pushd "$(dirname "$file")" > /dev/null
+
+          while read -r location; do
+            echo "Checking location $location"
+
+            if [[ "$location" == http* ]]; then
+              if ! curl --head --silent --fail "$location" 2>&1 > /dev/null; then
+                err "$file references non-existent image $location"
+                rc=1
+              fi
+            else
+              if [[ ! -f "$root$location" ]]; then
+                err "$file references non-existent image $location with imagedir ${root:-<null>}"
+                rc=1
+              fi
+            fi
+          done < <(grep -oE "image:+[^\[]*" "$(basename "$file")" | sed -E "s/^image:+//g")
+
+          popd > /dev/null
+        done < <(find . -type f -name "*.adoc")
+
+        exit $rc
+
+    - name: Verify absence of <img> tags
+      shell: bash
+      run: |
+        function err {
+          >&2 echo -e "\033[0;31m$@\033[0m"
+        }
+
+        rc=0
+
+        while read -r file; do
+          echo "Checking $file"
+
+          if grep -q "<img" "$file"; then
+            err "$file contains forbidden <img> tags. Use AsciiDoc image macros instead."
+          fi
+        done < <(find . -type f -name "*.adoc")
+
+        exit $rc

.github/actions/lint-drawio/action.yml

@@ -0,0 +1,24 @@
+name: Lint draw.io
+
+runs:
+  using: "composite"
+  steps:
+    - name: Verify number of diagrams
+      shell: bash
+      run: |
+        function err {
+          >&2 echo -e "\033[0;31m$@\033[0m"
+        }
+
+        rc=0
+
+        while read -r file; do
+          echo "Checking $file"
+
+          if [[ $(grep "<diag" "$file" | wc -l) -ne 1 ]]; then
+            err "$file does not contain exactly one diagram"
+            rc=1
+          fi
+        done < <(find . -name "*.drawio")
+
+        exit $rc

.github/actions/lint-plantuml/action.yml

@@ -0,0 +1,24 @@
+name: Lint PlantUML
+
+runs:
+  using: "composite"
+  steps:
+    - name: Verify absence of output file names
+      shell: bash
+      run: |
+        function err {
+          >&2 echo -e "\033[0;31m$@\033[0m"
+        }
+
+        rc=0
+
+        while read -r file; do
+          echo "Checking $file"
+
+          if grep -qE "^@startuml\s+." "$file"; then
+            err "$file contains forbidden output name in @startuml"
+            rc=1
+          fi
+        done < <(find . -name "*.puml")
+
+        exit $rc