gitlab-ci: Build on merge request, upload only on main branch commits

.gitlab-ci.yml

@@ -3,6 +3,7 @@
 # Only used in https://gitlab.com/fedora/ostree/ci-test
 # For tests running in the Fedora infrastructure, see .zuul.yaml and
 # https://fedoraproject.org/wiki/Zuul-based-ci
+# As those are not official images, we build all available variants
 
 # See: https://gitlab.com/fedora/ostree/buildroot
 image: quay.io/fedora-ostree-desktops/buildroot
@@ -10,8 +11,29 @@ image: quay.io/fedora-ostree-desktops/buildroot
 stages:
   - build
 
-# As those are not official images, we build all available variants
+# Only build the images for merge requests
 build:
+  stage: build
+  script:
+    - just compose-image $VARIANT
+  parallel:
+    matrix:
+    - VARIANT:
+      - silverblue
+      - kinoite
+      - kinoite-mobile
+      - sway-atomic
+      - xfce-atomic
+      - lxqt-atomic
+      - budgie-atomic
+      - base-atomic
+      # - kinoite-nightly
+      # - kinoite-devel
+  rules:
+  - if: $CI_PIPELINE_SOURCE == "merge_request_event"
+
+# Build and upload the images for commits pushed to the branch & scheduled pipelines
+build-upload:
   stage: build
   script:
     - just compose-image $VARIANT
@@ -30,3 +52,5 @@ build:
       - cosmic-atomic
       # - kinoite-nightly
       # - kinoite-devel
+  rules:
+  - if: $CI_COMMIT_BRANCH == "main" && ($CI_PIPELINE_SOURCE == "push" || $CI_PIPELINE_SOURCE == "schedule")