custom_hook: add support for global custom hooks

This commit adds the option of having another set of global custom hooks
along with the already supported repository local custom hooks.

The repository local custom hook is executed first (if available). If
successful, execution continues with the global custom hook (if available).
This way, local custom hooks get priority over global custom hooks.

Global custom hooks can be enabled by placing an executable file into the
"custom_hooks" directory within gitlab-shell (create if it does not exist,
yet).

.gitignore

@@ -8,3 +8,4 @@ coverage/
 .bundle
 tags
 .bundle/
+custom_hooks

hooks/post-receive

@@ -7,6 +7,7 @@ refs = $stdin.read
 key_id  = ENV.delete('GL_ID')
 repo_path = Dir.pwd
 
+require_relative '../lib/gitlab_init'
 require_relative '../lib/gitlab_custom_hook'
 require_relative '../lib/gitlab_post_receive'
 

hooks/pre-receive

@@ -8,6 +8,7 @@ key_id = ENV.delete('GL_ID')
 protocol = ENV.delete('GL_PROTOCOL')
 repo_path = Dir.pwd
 
+require_relative '../lib/gitlab_init'
 require_relative '../lib/gitlab_custom_hook'
 require_relative '../lib/gitlab_reference_counter'
 require_relative '../lib/gitlab_access'

hooks/update

@@ -9,6 +9,7 @@ new_value = ARGV[2]
 repo_path = Dir.pwd
 key_id    = ENV.delete('GL_ID')
 
+require_relative '../lib/gitlab_init'
 require_relative '../lib/gitlab_custom_hook'
 
 if GitlabCustomHook.new(repo_path, key_id).update(ref_name, old_value, new_value)

lib/gitlab_custom_hook.rb

@@ -11,28 +11,38 @@ class GitlabCustomHook
   end
 
   def pre_receive(changes)
-    hook = hook_file('pre-receive', @repo_path)
-    return true if hook.nil?
-
-    GitlabMetrics.measure("pre-receive-hook") { call_receive_hook(hook, changes) }
+    GitlabMetrics.measure("pre-receive-hook") do
+      find_hooks('pre-receive').all? do |hook|
+        call_receive_hook(hook, changes)
+      end
+    end
   end
 
   def post_receive(changes)
-    hook = hook_file('post-receive', @repo_path)
-    return true if hook.nil?
-
-    GitlabMetrics.measure("post-receive-hook") { call_receive_hook(hook, changes) }
+    GitlabMetrics.measure("post-receive-hook") do
+      find_hooks('post-receive').all? do |hook|
+        call_receive_hook(hook, changes)
+      end
+    end
   end
 
   def update(ref_name, old_value, new_value)
-    hook = hook_file('update', @repo_path)
-    return true if hook.nil?
-
-    GitlabMetrics.measure("update-hook") { system(vars, hook, ref_name, old_value, new_value) }
+    GitlabMetrics.measure("update-hook") do
+      find_hooks('update').all? do |hook|
+        system(vars, hook, ref_name, old_value, new_value)
+      end
+    end
   end
 
   private
 
+  def find_hooks(hook_name)
+    [
+      hook_file(hook_name, @repo_path),
+      hook_file(hook_name, ROOT_PATH)
+    ].compact
+  end
+
   def call_receive_hook(hook, changes)
     # Prepare the hook subprocess. Attach a pipe to its stdin, and merge
     # both its stdout and stderr into our own stdout.