ci: parallelize the mdbook build <language> process

Author: michael-kerscher

.github/workflows/build.sh

@@ -15,6 +15,19 @@ set -Eeuo pipefail
 book_lang=${1:?"Usage: $0 <book-lang> <dest-dir>"}
 dest_dir=${2:?"Usage: $0 <book-lang> <dest-dir>"}
 
+# ensure source dir exists
+mkdir -p source
+# clean previous build artifacts
+SOURCE_DIR="source/${book_lang}"
+rm -rf "$SOURCE_DIR"
+mkdir "$SOURCE_DIR"
+
+# clone the current state into the source directory
+git clone . "$SOURCE_DIR"
+
+# now work from that new directory as the base directory
+cd "$SOURCE_DIR"
+
 if [ "$book_lang" = "en" ]; then
  echo "::group::Building English course"
 else

.github/workflows/publish.yml

@@ -53,12 +53,10 @@ jobs:
  run: .github/workflows/build.sh en book
 
  - name: Build all translations
+ # note: build.sh here uses the given book path relative to source/{language}
  run: |
- for po_lang in ${{ env.LANGUAGES }}; do
- .github/workflows/build.sh $po_lang book/$po_lang
- mv book/$po_lang/html book/html/$po_lang
- done
-
+ parallel -i .github/workflows/build.sh {} book/{} -- ${{ env.LANGUAGES }}
+ parallel -i mv source/{}/book/{}/html book/html/{} -- ${{ env.LANGUAGES }}
  - name: Build translation report
  run: i18n-report report book/html/translation-report.html po/*.po