CE port for pipelines for external pull requestsce-detect-github-pull-requests

Detect if pipeline runs for a GitHub pull request

When using a mirror for CI/CD only we register a pull_request
webhook. When a pull_request webhook is received, if the
source branch SHA matches the actual head of the branch in the
repository we create immediately a new pipeline for the
external pull request. Otherwise we store the
pull request info for when the push webhook is received.

When using "only/except: external_pull_requests" we can detect
if the pipeline has a open pull request on GitHub and create or
not the job based on that.

1 files changed, 17 insertions, 0 deletions

diff --git a/db/migrate/20190830080123_add_index_to_ci_pipelines_external_pull_request.rb b/db/migrate/20190830080123_add_index_to_ci_pipelines_external_pull_request.rb
new file mode 100644
index 00000000000..d2f5ad7a420
--- /dev/null
+++ b/db/migrate/20190830080123_add_index_to_ci_pipelines_external_pull_request.rb
@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+
+class AddIndexToCiPipelinesExternalPullRequest < ActiveRecord::Migration[5.2]
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+
+  disable_ddl_transaction!
+
+  def up
+    add_concurrent_index :ci_pipelines, :external_pull_request_id, where: 'external_pull_request_id IS NOT NULL'
+  end
+
+  def down
+    remove_concurrent_index :ci_pipelines, :external_pull_request_id
+  end
+end