Trigger downstream pipeline only on PRs

.generated-pipeline.yml

@@ -0,0 +1,11 @@
+stages:
+  - placeholder
+
+# We need a placeholder success job because we can't trigger empty pipelines
+# Can be replaced by a useful gitlab job to run on non-PR commits
+success_job:
+  stage: placeholder
+  tags: ["arch:amd64"]
+  image: registry.ddbuild.io/ci/datadog-agent-buildimages/deb_x64:v48815877-9bfad02c
+  script:
+    - echo SUCCESS

.gitlab-ci-agent-build.yml

@@ -0,0 +1,103 @@
+include: "https://gitlab-templates.ddbuild.io/slack-notifier/v3-sdm/template.yml"
+
+stages:
+  - test
+  - after-test
+  - check-downstream
+  - notify
+
+# We're using two anchors because Gitlab doesn't allow us to use multiple anchors inside of a rules field.
+.skip_stable_branches: &skip_stable_branches
+  - if: $CI_COMMIT_BRANCH == $CI_DEFAULT_BRANCH
+    when: never
+  - if: $CI_COMMIT_BRANCH =~ /^7.[0-9]{2}.x/
+    when: never
+  - if: $CI_COMMIT_TAG != null
+    when: never
+  - changes:
+    - "**/*.rb"
+    - Rakefile
+    - omnibus-software.gemspec
+    - Gemfile
+    - .gitlab*
+    - .generated-pipeline.yml
+    - .gitlab-ci-agent-build.yml
+    when: always
+
+.on_success_skip_stable_branches: &on_success_skip_stable_branches
+  - if: $CI_COMMIT_BRANCH == $CI_DEFAULT_BRANCH
+    when: never
+  - if: $CI_COMMIT_BRANCH =~ /^7.[0-9]{2}.x/
+    when: never
+  - if: $CI_COMMIT_TAG != null
+    when: never
+  - changes:
+    - "**/*.rb"
+    - Rakefile
+    - omnibus-software.gemspec
+    - Gemfile
+    - .gitlab*
+    - .generated-pipeline.yml
+    - .gitlab-ci-agent-build.yml
+    when: on_success
+
+trigger-agent-build:
+  rules:
+    - *skip_stable_branches
+    - when: never
+  stage: test
+  trigger:
+    project: datadog/datadog-agent
+    strategy: depend
+  variables:
+    OMNIBUS_SOFTWARE_VERSION: $CI_COMMIT_BRANCH
+    RUN_ALL_BUILDS: "true"
+    RUN_KITCHEN_TESTS: "true"
+
+on_success:
+  rules:
+    - *on_success_skip_stable_branches
+    - when: always
+  stage: after-test
+  needs:
+    - job: "trigger-agent-build"
+      optional: true
+  tags: ["arch:amd64"]
+  image: registry.ddbuild.io/ci/datadog-agent-buildimages/deb_x64:v48815877-9bfad02c
+  script:
+    - echo success > output.pipeline
+  artifacts:
+    paths:
+      - output.pipeline
+    expire_in: 1 week
+
+# This job is monitored on github and acts as a required check.
+# A few details on the setup:
+# We can't monitor a trigger job from github, it has to have a script section.
+# We need the monitored job to fail if the downstream pipeline failed, and succeed if
+# the downstream pipeline succeeded. If the job is skipped, it isn't taken into account
+# on github.
+# This is where the on_success job kicks in. It run only if the previous job completes
+# and writes `success` in a file that's fetched by the `check-downstream-pipeline` job.
+# This allows us to have the check-downstream-pipeline to always run while replicating
+# the status of the downstream pipeline.
+check-downstream-pipeline:
+  rules:
+    - *skip_stable_branches
+    - when: always
+  stage: check-downstream
+  tags: ["arch:amd64"]
+  image: registry.ddbuild.io/ci/datadog-agent-buildimages/deb_x64:v48815877-9bfad02c
+  script:
+    - cat output.pipeline
+
+notify:
+  extends: .slack-notifier-base
+  stage: notify
+  dependencies: []
+  rules:
+    - *skip_stable_branches
+    - when: never
+  script: |
+    export MESSAGE="Your omnibus-software test pipeline completed"
+    /usr/local/bin/notify.sh

.gitlab-ci.yml

@@ -1,97 +1,37 @@
-include: "https://gitlab-templates.ddbuild.io/slack-notifier/v3-sdm/template.yml"
-
 stages:
-  - test
-  - after-test
-  - check-downstream
-  - notify
-
-# We're using two anchors because Gitlab doesn't allow us to use multiple anchors inside of a rules field.
-.skip_stable_branches: &skip_stable_branches
-  - if: $CI_COMMIT_BRANCH == $CI_DEFAULT_BRANCH
-    when: never
-  - if: $CI_COMMIT_BRANCH =~ /^7.[0-9]{2}.x/
-    when: never
-  - if: $CI_COMMIT_TAG != null
-    when: never
-  - changes:
-    - "**/*.rb"
-    - Rakefile
-    - omnibus-software.gemspec
-    - Gemfile
-    when: always
+  - generation
+  - trigger
 
-.on_success_skip_stable_branches: &on_success_skip_stable_branches
-  - if: $CI_COMMIT_BRANCH == $CI_DEFAULT_BRANCH
-    when: never
-  - if: $CI_COMMIT_BRANCH =~ /^7.[0-9]{2}.x/
-    when: never
-  - if: $CI_COMMIT_TAG != null
-    when: never
-  - changes:
-    - "**/*.rb"
-    - Rakefile
-    - omnibus-software.gemspec
-    - Gemfile
-    when: on_success
-
-trigger-agent-build:
-  rules:
-    - *skip_stable_branches
-    - when: never
-  stage: test
-  trigger:
-    project: datadog/datadog-agent
-    strategy: depend
-  variables:
-    OMNIBUS_SOFTWARE_VERSION: $CI_COMMIT_BRANCH
-    RUN_ALL_BUILDS: "true"
-    RUN_KITCHEN_TESTS: "true"
-
-on_success:
-  rules:
-    - *on_success_skip_stable_branches
-    - when: always
-  stage: after-test
-  needs:
-    - job: "trigger-agent-build"
-      optional: true
+check_if_branch_is_a_pr:
+  stage: generation
   tags: ["arch:amd64"]
   image: registry.ddbuild.io/ci/datadog-agent-buildimages/deb_x64:v48815877-9bfad02c
-  script:
-    - echo success > output.pipeline
+  allow_failure: true
+  script: |
+    cp .generated-pipeline.yml generated-pipeline.yml
+    # Check if our current branch is inside the PR list of omnibus-software
+    curl https://api.github.com/repos/DataDog/omnibus-software/pulls
+    if curl https://api.github.com/repos/DataDog/omnibus-software/pulls | grep "$CI_COMMIT_REF_NAME"
+    then
+      echo "Current commit is on a PR"
+      cp .gitlab-ci-agent-build.yml generated-pipeline.yml
+    else
+      echo "Current commit is not on a PR"
+    fi
   artifacts:
+    untracked: true
+    expire_in: 1h
     paths:
-      - output.pipeline
-    expire_in: 1 week
+      - generated-pipeline.yml
+
+trigger_pipeline:
+  stage: trigger
+  needs:
+    - job: check_if_branch_is_a_pr
+      artifacts: true
+  trigger:
+    include:
+      - artifact: generated-pipeline.yml
+        job: check_if_branch_is_a_pr
 
-# This job is monitored on github and acts as a required check.
-# A few details on the setup:
-# We can't monitor a trigger job from github, it has to have a script section.
-# We need the monitored job to fail if the downstream pipeline failed, and succeed if
-# the downstream pipeline succeeded. If the job is skipped, it isn't taken into account
-# on github.
-# This is where the on_success job kicks in. It run only if the previous job completes
-# and writes `success` in a file that's fetched by the `check-downstream-pipeline` job.
-# This allows us to have the check-downstream-pipeline to always run while replicating
-# the status of the downstream pipeline.
-check-downstream-pipeline:
-  rules:
-    - *skip_stable_branches
-    - when: always
-  stage: check-downstream
-  tags: ["arch:amd64"]
-  image: registry.ddbuild.io/ci/datadog-agent-buildimages/deb_x64:v48815877-9bfad02c
-  script:
-    - cat output.pipeline
 
-notify:
-  extends: .slack-notifier-base
-  stage: notify
-  dependencies: []
-  rules:
-    - *skip_stable_branches
-    - when: never
-  script: |
-    export MESSAGE="Your omnibus-software test pipeline completed"
-    /usr/local/bin/notify.sh