Fix username and ID not logging in production_json.log for Git activity

Devise sets `current_user`, but not all controllers authenticate users by
session tokens. Try to use the controller-defined `authenticated_user` if
`current_user` is not available.

Closes gitlab-org/gitlab-ee#3611

app/controllers/application_controller.rb

@@ -85,12 +85,21 @@ class ApplicationController < ActionController::Base
     super
     payload[:remote_ip] = request.remote_ip
 
-    if current_user.present?
-      payload[:user_id] = current_user.id
-      payload[:username] = current_user.username
+    logged_user = auth_user
+
+    if logged_user.present?
+      payload[:user_id] = logged_user.try(:id)
+      payload[:username] = logged_user.try(:username)
     end
   end
 
+  # Controllers such as GitHttpController may use alternative methods
+  # (e.g. tokens) to authenticate the user, whereas Devise sets current_user
+  def auth_user
+    return current_user if current_user.present?
+    return try(:authenticated_user)
+  end
+
   # This filter handles both private tokens and personal access tokens
   def authenticate_user_from_private_token!
     token = params[:private_token].presence || request.headers['PRIVATE-TOKEN'].presence

app/controllers/projects/git_http_client_controller.rb

@@ -9,6 +9,7 @@ class Projects::GitHttpClientController < Projects::ApplicationController
   delegate :actor, :authentication_abilities, to: :authentication_result, allow_nil: true
 
   alias_method :user, :actor
+  alias_method :authenticated_user, :actor
 
   # Git clients will not know what authenticity token to send along
   skip_before_action :verify_authenticity_token

changelogs/unreleased/sh-fix-username-logging.yml

+---
+title: Fix username and ID not logging in production_json.log for Git activity
+merge_request:
+author:
+type: fixed