Ignore errors early, to avoid creating extra WorkflowRuns

src/api/app/controllers/concerns/rescue_handler.rb

@@ -30,6 +30,10 @@ module RescueHandler
       render_error status: 403, errorcode: 'invalid_token', message: exception.message
     end
 
+    rescue_from Trigger::Errors::MissingExtractor do |exception|
+      render_error status: 400, errorcode: 'bad_request', message: exception.message
+    end
+
     rescue_from Project::WritePermissionError do |exception|
       render_error status: 403, errorcode: 'modify_project_no_permission', message: exception.message
     end

src/api/app/controllers/concerns/scm_webhook_headers_data_extractor.rb

@@ -23,6 +23,15 @@ def hook_event
     @github_event || @gitlab_event || @gitea_event
   end
 
+  def ignored_event?
+    case scm_vendor
+    when 'github', 'gitea'
+      SCMWebhookEventValidator::ALLOWED_GITHUB_AND_GITEA_EVENTS.exclude?(hook_event)
+    when 'gitlab'
+      SCMWebhookEventValidator::ALLOWED_GITLAB_EVENTS.exclude?(hook_event)
+    end
+  end
+
   def extract_generic_event_type
     # We only have filters for push, tag_push, and pull_request
     if hook_event == 'Push Hook' || payload.fetch('ref', '').match('refs/heads')

src/api/app/controllers/trigger/errors.rb

@@ -5,6 +5,10 @@ class InvalidToken < APIError
           'No valid token found'
   end
 
+  class MissingExtractor < APIError
+    setup 'bad_request', 400, 'Extractor could not be created.'
+  end
+
   class BadSCMPayload < APIError
     setup 'bad_request',
           400,

src/api/app/controllers/trigger_workflow_controller.rb

@@ -8,6 +8,7 @@ class TriggerWorkflowController < TriggerController
   before_action :set_scm_event
   before_action :set_scm_extractor
   before_action :extract_scm_webhook
+  before_action :verify_event_and_action
   before_action :create_workflow_run
   before_action :validate_scm_event
 
@@ -40,10 +41,9 @@ def set_scm_extractor
 
   def extract_scm_webhook
     @scm_webhook = @scm_extractor.call
+    return @scm_webhook if @scm_webhook && @scm_extractor.valid?
 
-    # There are plenty of different pull/merge request and push events which we don't support.
-    # Those should not cause an error, we simply ignore them.
-    render_ok if @scm_webhook && (@scm_webhook.ignored_pull_request_action? || @scm_webhook.ignored_push_event?)
+    raise Trigger::Errors::MissingExtractor, @scm_extractor.error_message
   end
 
   def create_workflow_run
@@ -63,6 +63,20 @@ def create_workflow_run
                                                 generic_event_type: extract_generic_event_type)
   end
 
+  def verify_event_and_action
+    # There are plenty of different pull/merge request and push events which we don't support.
+    # Those should not cause an error, we simply ignore them.
+    return unless @scm_webhook.ignored_pull_request_action? || @scm_webhook.ignored_push_event? || ignored_event?
+
+    action = @scm_webhook.payload[:action]
+
+    info_msg = "Events '#{@scm_webhook.payload[:event]}' "
+    info_msg += "and actions '#{action}' " if action.present?
+    info_msg += 'are unsupported'
+
+    render_ok(data: { info: info_msg })
+  end
+
   def validate_scm_event
     return if @scm_extractor.valid?
 

src/api/spec/controllers/trigger_workflow_controller_spec.rb

@@ -164,7 +164,7 @@
       end
 
       it { expect(response).to have_http_status(:bad_request) }
-      it { expect(WorkflowRun.count).to eq(1) }
+      it { expect(WorkflowRun.count).to eq(0) }
 
       it 'returns an error message in the response body' do
         expect(response.body).to eql("<status code=\"bad_request\">\n  <summary>This SCM event is not supported</summary>\n</status>\n")