1 files changed, 57 insertions, 0 deletions
diff --git a/app/services/ci/prometheus_metrics/observe_histograms_service.rb b/app/services/ci/prometheus_metrics/observe_histograms_service.rb
new file mode 100644
index 00000000000..ee22ea75df9
--- /dev/null
+++ b/app/services/ci/prometheus_metrics/observe_histograms_service.rb
@@ -0,0 +1,57 @@
+# frozen_string_literal: true
+
+module Ci
+  module PrometheusMetrics
+    class ObserveHistogramsService
+      class << self
+        def available_histograms
+          @available_histograms ||= [
+            histogram(:pipeline_graph_link_calculation_duration_seconds, 'Total time spent calculating links, in seconds', {}, [0.05, 0.1, 0.2, 0.3, 0.4, 0.5, 0.8, 1, 2]),
+            histogram(:pipeline_graph_links_total, 'Number of links per graph', {}, [1, 5, 10, 25, 50, 100, 200]),
+            histogram(:pipeline_graph_links_per_job_ratio, 'Ratio of links to job per graph', {}, [0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1])
+          ].to_h
+        end
+
+        private
+
+        def histogram(name, *attrs)
+          [name.to_s, proc { Gitlab::Metrics.histogram(name, *attrs) }]
+        end
+      end
+
+      def initialize(project, params)
+        @project = project
+        @params = params
+      end
+
+      def execute
+        return ServiceResponse.success(http_status: :accepted) unless enabled?
+
+        params
+          .fetch(:histograms, [])
+          .each(&method(:observe))
+
+        ServiceResponse.success(http_status: :created)
+      end
+
+      private
+
+      attr_reader :project, :params
+
+      def observe(data)
+        histogram = find_histogram(data[:name])
+        histogram.observe({ project: project.full_path }, data[:value].to_f)
+      end
+
+      def find_histogram(name)
+        self.class.available_histograms
+          .fetch(name) { raise ActiveRecord::RecordNotFound }
+          .call
+      end
+
+      def enabled?
+        ::Feature.enabled?(:ci_accept_frontend_prometheus_metrics, project, default_enabled: :yaml)
+      end
+    end
+  end
+end