Extract common validations from ci services

DroneCI and TeamCity shared the same validations methods
on the data received. These validations were extracted
into a concern

3 files changed, 57 insertions, 48 deletions

diff --git a/app/models/concerns/service_push_data_validations.rb b/app/models/concerns/service_push_data_validations.rb
new file mode 100644
index 00000000000..defc5794142
--- /dev/null
+++ b/app/models/concerns/service_push_data_validations.rb
@@ -0,0 +1,43 @@
+# frozen_string_literal: true
+
+# This concern is used by registerd services such as TeamCityService and
+# DroneCiService and add methods to perform validations on the received
+# data.
+
+module ServicePushDataValidations
+  extend ActiveSupport::Concern
+
+  def merge_request_valid?(data)
+    data.dig(:object_attributes, :state) == 'opened' && merge_request_unchecked?(data)
+  end
+
+  def push_valid?(data)
+    data[:total_commits_count] > 0 &&
+      !branch_removed?(data) &&
+      # prefer merge request trigger over push to avoid double builds
+      !opened_merge_requests?(data)
+  end
+
+  def tag_push_valid?(data)
+    data[:total_commits_count] > 0 && !branch_removed?(data)
+  end
+
+  private
+
+  def branch_removed?(data)
+    Gitlab::Git.blank_ref?(data[:after])
+  end
+
+  def opened_merge_requests?(data)
+    project.merge_requests
+      .opened
+      .from_project(project)
+      .from_source_branches(Gitlab::Git.ref_name(data[:ref]))
+      .exists?
+  end
+
+  def merge_request_unchecked?(data)
+    MergeRequest.state_machines[:merge_status]
+      .check_state?(data.dig(:object_attributes, :merge_status))
+  end
+end
diff --git a/app/models/project_services/drone_ci_service.rb b/app/models/project_services/drone_ci_service.rb
index 5ccc2f019cb..dbdc8345c93 100644
--- a/app/models/project_services/drone_ci_service.rb
+++ b/app/models/project_services/drone_ci_service.rb
@@ -2,6 +2,7 @@
 
 class DroneCiService < CiService
   include ReactiveService
+  include ServicePushDataValidations
 
   prop_accessor :drone_url, :token
   boolean_accessor :enable_ssl_verification
@@ -96,23 +97,4 @@ class DroneCiService < CiService
       { type: 'checkbox', name: 'enable_ssl_verification', title: "Enable SSL verification" }
     ]
   end
-
-  private
-
-  def tag_push_valid?(data)
-    data[:total_commits_count] > 0 && !Gitlab::Git.blank_ref?(data[:after])
-  end
-
-  def push_valid?(data)
-    opened_merge_requests = project.merge_requests.opened.where(source_project_id: project.id,
-                                                                source_branch: Gitlab::Git.ref_name(data[:ref]))
-
-    opened_merge_requests.empty? && data[:total_commits_count] > 0 &&
-      !Gitlab::Git.blank_ref?(data[:after])
-  end
-
-  def merge_request_valid?(data)
-    data[:object_attributes][:state] == 'opened' &&
-      MergeRequest.state_machines[:merge_status].check_state?(data[:object_attributes][:merge_status])
-  end
 end
diff --git a/app/models/project_services/teamcity_service.rb b/app/models/project_services/teamcity_service.rb
index 918a1b32612..68c07fa37f2 100644
--- a/app/models/project_services/teamcity_service.rb
+++ b/app/models/project_services/teamcity_service.rb
@@ -2,6 +2,7 @@
 
 class TeamcityService < CiService
   include ReactiveService
+  include ServicePushDataValidations
 
   prop_accessor :teamcity_url, :build_type, :username, :password
 
@@ -89,20 +90,26 @@ class TeamcityService < CiService
   end
 
   def execute(data)
-    return unless supported_events.include?(data[:object_kind])
-
     case data[:object_kind]
     when 'push'
-      branch = Gitlab::Git.ref_name(data[:ref])
-      post_to_build_queue(data, branch) if push_valid?(data)
+      execute_push(data)
     when 'merge_request'
-      branch = data[:object_attributes][:source_branch]
-      post_to_build_queue(data, branch) if merge_request_valid?(data)
+      execute_merge_request(data)
     end
   end
 
   private
 
+  def execute_push(data)
+    branch = Gitlab::Git.ref_name(data[:ref])
+    post_to_build_queue(data, branch) if push_valid?(data)
+  end
+
+  def execute_merge_request(data)
+    branch = data[:object_attributes][:source_branch]
+    post_to_build_queue(data, branch) if merge_request_valid?(data)
+  end
+
   def read_build_page(response)
     if response.code != 200
       # If actual build link can't be determined,
@@ -159,27 +166,4 @@ class TeamcityService < CiService
   def basic_auth
     { username: username, password: password }
   end
-
-  def push_valid?(data)
-    data[:total_commits_count] > 0 &&
-      !branch_removed?(data) &&
-      no_open_merge_requests?(data)
-  end
-
-  def merge_request_valid?(data)
-    data.dig(:object_attributes, :state) == 'opened' &&
-      MergeRequest.state_machines[:merge_status].check_state?(data.dig(:object_attributes, :merge_status))
-  end
-
-  def branch_removed?(data)
-    Gitlab::Git.blank_ref?(data[:after])
-  end
-
-  def no_open_merge_requests?(data)
-    !project.merge_requests
-      .opened
-      .from_project(project)
-      .from_source_branches(Gitlab::Git.ref_name(data[:ref]))
-      .exists?
-  end
 end