require 'prometheus/client' module Gitlab module Metrics module Prometheus extend ActiveSupport::Concern REGISTRY_MUTEX = Mutex.new PROVIDER_MUTEX = Mutex.new class_methods do include Gitlab::Utils::StrongMemoize def metrics_folder_present? multiprocess_files_dir = ::Prometheus::Client.configuration.multiprocess_files_dir multiprocess_files_dir && ::Dir.exist?(multiprocess_files_dir) && ::File.writable?(multiprocess_files_dir) end def prometheus_metrics_enabled? strong_memoize(:prometheus_metrics_enabled) do prometheus_metrics_enabled_unmemoized end end def registry strong_memoize(:registry) do REGISTRY_MUTEX.synchronize do strong_memoize(:registry) do ::Prometheus::Client.registry end end end end def counter(name, docstring, base_labels = {}) safe_provide_metric(:counter, name, docstring, base_labels) end def summary(name, docstring, base_labels = {}) safe_provide_metric(:summary, name, docstring, base_labels) end def gauge(name, docstring, base_labels = {}, multiprocess_mode = :all) safe_provide_metric(:gauge, name, docstring, base_labels, multiprocess_mode) end def histogram(name, docstring, base_labels = {}, buckets = ::Prometheus::Client::Histogram::DEFAULT_BUCKETS) safe_provide_metric(:histogram, name, docstring, base_labels, buckets) end private def safe_provide_metric(method, name, *args) metric = provide_metric(name) return metric if metric PROVIDER_MUTEX.synchronize do provide_metric(name) || registry.method(method).call(name, *args) end end def provide_metric(name) if prometheus_metrics_enabled? registry.get(name) else NullMetric.instance end end def prometheus_metrics_enabled_unmemoized metrics_folder_present? && Gitlab::CurrentSettings.prometheus_metrics_enabled || false end end end end end