1# frozen_string_literal: true 2 3module HasUniqueInternalUsers 4 extend ActiveSupport::Concern 5 6 class_methods do 7 private 8 9 def unique_internal(scope, username, email_pattern, &block) 10 scope.first || create_unique_internal(scope, username, email_pattern, &block) 11 end 12 13 def create_unique_internal(scope, username, email_pattern, &creation_block) 14 # Since we only want a single one of these in an instance, we use an 15 # exclusive lease to ensure than this block is never run concurrently. 16 lease_key = "user:unique_internal:#{username}" 17 lease = Gitlab::ExclusiveLease.new(lease_key, timeout: 1.minute.to_i) 18 19 until uuid = lease.try_obtain 20 # Keep trying until we obtain the lease. To prevent hammering Redis too 21 # much we'll wait for a bit between retries. 22 sleep(1) 23 end 24 25 # Recheck if the user is already present. One might have been 26 # added between the time we last checked (first line of this method) 27 # and the time we acquired the lock. 28 existing_user = uncached { scope.first } 29 return existing_user if existing_user.present? 30 31 uniquify = Uniquify.new 32 33 username = uniquify.string(username) { |s| User.find_by_username(s) } 34 35 email = uniquify.string(-> (n) { Kernel.sprintf(email_pattern, n) }) do |s| 36 User.find_by_email(s) 37 end 38 39 user = scope.build( 40 username: username, 41 email: email, 42 &creation_block 43 ) 44 45 Users::UpdateService.new(user, user: user).execute(validate: false) 46 user 47 ensure 48 Gitlab::ExclusiveLease.cancel(lease_key, uuid) 49 end 50 end 51end 52