feat: automatic repo version selection via YAML configuration

You can now define your custom repos with the `%FEDORA_VERSION%` variable, to automatically use the correct repo version, so that you never have to maintain their custom URLs again in the future.

build.sh

@@ -12,11 +12,15 @@ get_yaml_string() {
     yq -- "$1" "$RECIPE_FILE"
 }
 
+# Read configuration variables.
+fedora_version="$(get_yaml_string '.fedora-version')"
+
 # Add custom repos.
 get_yaml_array repos '.extrarepos[]'
 if [[ ${#repos[@]} -gt 0 ]]; then
     echo "-- Adding repos defined in recipe.yml --"
     for repo in "${repos[@]}"; do
+        repo="${repo//%FEDORA_VERSION%/${fedora_version}}"
         wget "$repo" -P /etc/yum.repos.d/
     done
     echo "---"

recipe.yml

@@ -26,9 +26,12 @@ scripts:
 
 # A list of urls of ".repo" files that should be added to your system.
 # This is the proper way to add custom COPR repos to your image.
+# Tip: Use `%FEDORA_VERSION%` instead of static Fedora version numbers, so that
+# your repos automatically use the Fedora version defined in `fedora-version`,
+# which greatly simplifies future maintenance of your custom recipe.
 extrarepos:
-  # example:
-  # - https://copr.fedorainfracloud.org/coprs/atim/starship/repo/fedora-38/atim-starship-fedora-38.repo
+  # Example (which also demonstrates version number expansion):
+  # - https://copr.fedorainfracloud.org/coprs/atim/starship/repo/fedora-%FEDORA_VERSION%/atim-starship-fedora-%FEDORA_VERSION%.repo
 
 # These RPMs will be removed from the system image. This step happens during
 # image build, before installing custom RPMs (from the "rpm-install" category).