Filter project hooks by branch

Allow specificying a branch filter for a project hook and only trigger
a project hook if either the branch filter is blank or the branch matches.
Only supported for push_events for now.

6 files changed, 76 insertions, 2 deletions

diff --git a/app/controllers/projects/hooks_controller.rb b/app/controllers/projects/hooks_controller.rb
index 2da2aad9b33..bbf8c7d5cbc 100644
--- a/app/controllers/projects/hooks_controller.rb
+++ b/app/controllers/projects/hooks_controller.rb
@@ -66,6 +66,7 @@ class Projects::HooksController < Projects::ApplicationController
       :enable_ssl_verification,
       :token,
       :url,
+      :push_events_branch_filter,
       *ProjectHook.triggers.values
     )
   end
diff --git a/app/models/hooks/active_hook_filter.rb b/app/models/hooks/active_hook_filter.rb
new file mode 100644
index 00000000000..611af971163
--- /dev/null
+++ b/app/models/hooks/active_hook_filter.rb
@@ -0,0 +1,38 @@
+class ActiveHookFilter
+  def initialize(hook)
+    @hook = hook
+  end
+
+  def matches?(hooks_scope, data)
+    return true if hooks_scope != :push_hooks
+    return true if @hook.push_events_branch_filter.blank?
+
+    branch_name = Gitlab::Git.branch_name(data[:ref])
+    exact_match?(branch_name) || wildcard_match?(branch_name)
+  end
+
+  private
+
+  def exact_match?(branch_name)
+    @hook.push_events_branch_filter == branch_name
+  end
+
+  def wildcard_match?(branch_name)
+    return false unless wildcard?
+
+    wildcard_regex === branch_name
+  end
+
+  def wildcard_regex
+    @wildcard_regex ||= begin
+      name = @hook.push_events_branch_filter.gsub('*', 'STAR_DONT_ESCAPE')
+      quoted_name = Regexp.quote(name)
+      regex_string = quoted_name.gsub('STAR_DONT_ESCAPE', '.*?')
+      /\A#{regex_string}\z/
+    end
+  end
+
+  def wildcard?
+    @hook.push_events_branch_filter && @hook.push_events_branch_filter.include?('*')
+  end
+end
diff --git a/app/models/hooks/web_hook.rb b/app/models/hooks/web_hook.rb
index f18aadefa5c..20f15c15277 100644
--- a/app/models/hooks/web_hook.rb
+++ b/app/models/hooks/web_hook.rb
@@ -9,6 +9,7 @@ class WebHook < ActiveRecord::Base
                                                 allow_local_network: lambda(&:allow_local_requests?) }
 
   validates :token, format: { without: /\n/ }
+  validates :push_events_branch_filter, branch_filter: true
 
   def execute(data, hook_name)
     WebHookService.new(self, data, hook_name).execute
diff --git a/app/models/project.rb b/app/models/project.rb
index 7735f23cb9e..72a53e1a50d 100644
--- a/app/models/project.rb
+++ b/app/models/project.rb
@@ -1163,10 +1163,9 @@ class Project < ActiveRecord::Base
 
   def execute_hooks(data, hooks_scope = :push_hooks)
     run_after_commit_or_now do
-      hooks.hooks_for(hooks_scope).each do |hook|
+      hooks.hooks_for(hooks_scope).select {|hook| ActiveHookFilter.new(hook).matches?(hooks_scope, data)}.each do |hook|
         hook.async_execute(data, hooks_scope.to_s)
       end
-
       SystemHooksService.new.execute_hooks(data, hooks_scope)
     end
   end
diff --git a/app/validators/branch_filter_validator.rb b/app/validators/branch_filter_validator.rb
new file mode 100644
index 00000000000..0965be3d101
--- /dev/null
+++ b/app/validators/branch_filter_validator.rb
@@ -0,0 +1,34 @@
+# BranchFilterValidator
+#
+# Custom validator for branch names. Squishes whitespace and ignores empty
+# string.  This only checks that a string is a valid git branch name. It does
+# not check whether a branch already exists.
+#
+# Example:
+#
+#   class Webhook < ActiveRecord::Base
+#     validates :push_events_branch_filter, branch_name: true
+#   end
+#
+class BranchFilterValidator < ActiveModel::EachValidator
+  def validate_each(record, attribute, value)
+    value.squish! unless value.nil?
+
+    if value.present?
+      value_without_wildcards = value.tr('*', 'x')
+      unless Gitlab::GitRefValidator.validate(value_without_wildcards)
+        record.errors[attribute] << "is not a valid branch name"
+      end
+
+      unless value.length <= 4000
+        record.errors[attribute] << "is longer than the allowed length of 4000 characters."
+      end
+    end
+  end
+
+  private
+
+  def contains_wildcard?(value)
+    value.include?('*')
+  end
+end
diff --git a/app/views/shared/web_hooks/_form.html.haml b/app/views/shared/web_hooks/_form.html.haml
index 07ebb8680d2..9c5b9593bba 100644
--- a/app/views/shared/web_hooks/_form.html.haml
+++ b/app/views/shared/web_hooks/_form.html.haml
@@ -17,6 +17,7 @@
         %strong Push events
       %p.light.ml-1
         This URL will be triggered by a push to the repository
+        = form.text_field :push_events_branch_filter, class: 'form-control', placeholder: 'Branch name or wildcard pattern to trigger on (leave blank for all)'
     %li
       = form.check_box :tag_push_events, class: 'form-check-input'
       = form.label :tag_push_events, class: 'list-label form-check-label ml-1' do