1# frozen_string_literal: true
2
3module Gitlab
4  module Metrics
5    # Exclusive transaction-type metrics for background jobs (Sidekiq). One
6    # instance of this class is created for each job going through the Sidekiq
7    # metric middleware. Any metrics dispatched with this instance include
8    # metadata such as endpoint_id, queue, and feature category.
9    class BackgroundTransaction < Transaction
10      THREAD_KEY = :_gitlab_metrics_background_transaction
11      BASE_LABEL_KEYS = %i(queue endpoint_id feature_category).freeze
12
13      class << self
14        def current
15          Thread.current[THREAD_KEY]
16        end
17
18        def prometheus_metric(name, type, &block)
19          fetch_metric(type, name) do
20            # set default metric options
21            docstring "#{name.to_s.humanize} #{type}"
22
23            evaluate(&block)
24            # always filter sensitive labels and merge with base ones
25            label_keys BASE_LABEL_KEYS | (label_keys - ::Gitlab::Metrics::Transaction::FILTERED_LABEL_KEYS)
26          end
27        end
28      end
29
30      def run
31        Thread.current[THREAD_KEY] = self
32
33        yield
34      ensure
35        Thread.current[THREAD_KEY] = nil
36      end
37
38      def labels
39        @labels ||= {
40          endpoint_id: endpoint_id,
41          feature_category: feature_category,
42          queue: queue
43        }
44      end
45
46      private
47
48      def current_context
49        Labkit::Context.current
50      end
51
52      def feature_category
53        current_context&.get_attribute(:feature_category)
54      end
55
56      def endpoint_id
57        current_context&.get_attribute(:caller_id)
58      end
59
60      def queue
61        worker_class = endpoint_id.to_s.safe_constantize
62        return if worker_class.blank? || !worker_class.respond_to?(:queue)
63
64        worker_class.queue.to_s
65      end
66    end
67  end
68end
69