From 9be0c2734ae3e3cc84196cf167a0c327c7cf8570 Mon Sep 17 00:00:00 2001
From: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>
Date: Thu, 8 Feb 2018 17:51:02 +0200
Subject: [PATCH] Add external plugins support to extend system hooks

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>
---
 app/services/system_hooks_service.rb |  9 +++++++++
 config/application.rb                |  1 +
 config/initializers/9_plugins.rb     | 29 ++++++++++++++++++++++++++++
 3 files changed, 39 insertions(+)
 create mode 100644 config/initializers/9_plugins.rb

diff --git a/app/services/system_hooks_service.rb b/app/services/system_hooks_service.rb
index a6b7a6e1416..71de74e5a82 100644
--- a/app/services/system_hooks_service.rb
+++ b/app/services/system_hooks_service.rb
@@ -11,6 +11,15 @@ class SystemHooksService
     SystemHook.hooks_for(hooks_scope).find_each do |hook|
       hook.async_execute(data, 'system_hooks')
     end
+
+    # Execute external plugins
+    PLUGINS.each do |plugin|
+      begin
+        plugin.new.execute(data)
+      rescue => e
+        Rails.logger.warn("GitLab -> Plugins -> #{plugin.class.name} raised an axception during execution. #{e}")
+      end
+    end
   end
 
   private
diff --git a/config/application.rb b/config/application.rb
index 918bd4d57cf..f2fc6270748 100644
--- a/config/application.rb
+++ b/config/application.rb
@@ -28,6 +28,7 @@ module Gitlab
     config.eager_load_paths.push(*%W[#{config.root}/lib
                                      #{config.root}/app/models/hooks
                                      #{config.root}/app/models/members
+                                     #{config.root}/plugins
                                      #{config.root}/app/models/project_services
                                      #{config.root}/app/workers/concerns
                                      #{config.root}/app/services/concerns
diff --git a/config/initializers/9_plugins.rb b/config/initializers/9_plugins.rb
new file mode 100644
index 00000000000..9f252ccd296
--- /dev/null
+++ b/config/initializers/9_plugins.rb
@@ -0,0 +1,29 @@
+class PluginsSystem
+  attr_accessor :plugins, :files
+
+  def initialize
+    @files = Dir.glob(Rails.root.join('plugins', '*_plugin.rb'))
+  end
+
+  def valid_plugins
+    files.map do |file|
+      file_name = File.basename(file, '.rb')
+
+      # Just give sample data to method and expect it to not crash.
+      begin
+        klass = Object.const_get(file_name.classify)
+        klass.new.execute(Gitlab::DataBuilder::Push::SAMPLE_DATA)
+      rescue => e
+        Rails.logger.warn("GitLab -> Plugins -> #{file_name} raised an exception during boot check. #{e}")
+        next
+      else
+        Rails.logger.info "GitLab -> Plugins -> #{file_name} passed boot check"
+        klass
+      end
+    end
+  end
+end
+
+# Load external plugins from /plugins directory
+# and set into PLUGINS variable
+PLUGINS = PluginsSystem.new.valid_plugins