CE port for pipelines for external 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, 25 insertions, 0 deletions

diff --git a/db/migrate/20190829131130_create_external_pull_requests.rb b/db/migrate/20190829131130_create_external_pull_requests.rb
new file mode 100644
index 00000000000..0c3168807ec
--- /dev/null
+++ b/db/migrate/20190829131130_create_external_pull_requests.rb
@@ -0,0 +1,25 @@
+# frozen_string_literal: true
+
+class CreateExternalPullRequests < ActiveRecord::Migration[5.2]
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+  INDEX = 'index_external_pull_requests_on_project_and_branches'
+
+  def change
+    create_table :external_pull_requests do |t|
+      t.timestamps_with_timezone null: false
+      t.references :project, null: false, foreign_key: { on_delete: :cascade }, index: false
+      t.integer :pull_request_iid, null: false
+      t.integer :status, null: false, limit: 2
+      t.string :source_branch, null: false, limit: 255
+      t.string :target_branch, null: false, limit: 255
+      t.string :source_repository, null: false, limit: 255
+      t.string :target_repository, null: false, limit: 255
+      t.binary :source_sha, null: false
+      t.binary :target_sha, null: false
+
+      t.index [:project_id, :source_branch, :target_branch], unique: true, name: INDEX
+    end
+  end
+end