1 files changed, 72 insertions, 0 deletions
diff --git a/lib/gitlab/prometheus/queries/matched_metrics_query.rb b/lib/gitlab/prometheus/queries/matched_metrics_query.rb
new file mode 100644
index 00000000000..61926320e40
--- /dev/null
+++ b/lib/gitlab/prometheus/queries/matched_metrics_query.rb
@@ -0,0 +1,72 @@
+module Gitlab::Prometheus::Queries
+  class MatchedMetricsQuery < BaseQuery
+    MAX_QUERY_ITEMS = 40.freeze
+
+    def self.metrics
+      @metrics ||= YAML.load_file(Rails.root.join('config/additional_metrics.yml')).map(&:deep_symbolize_keys)
+    end
+
+    def query
+      groups_data.map do |group, data|
+        {
+          group: group.name,
+          priority: group.priority,
+          active_metrics: data[:active_metrics],
+          metrics_missing_requirements: data[:metrics_missing_requirements]
+        }
+      end
+    end
+
+    def groups_data
+      metrics_series = metrics_with_series(Gitlab::Prometheus::MetricGroup.all)
+      lookup = active_series_lookup(metrics_series)
+
+      groups = {}
+
+      metrics_series.each do |metrics, series|
+        groups[metrics.group] ||= { active_metrics: 0, metrics_missing_requirements: 0 }
+        group = groups[metrics.group]
+
+        if series.all?(&lookup.method(:has_key?))
+          group[:active_metrics] += 1
+        else
+          group[:metrics_missing_requirements] += 1
+        end
+        group
+      end
+
+      groups
+    end
+
+    def active_series_lookup(metrics)
+      timeframe_start = 8.hours.ago
+      timeframe_end = Time.now
+
+      series = metrics.flat_map { |metrics, series| series }.uniq
+
+      lookup = series.each_slice(MAX_QUERY_ITEMS).flat_map do |batched_series|
+        client_series(*batched_series, start: timeframe_start, stop: timeframe_end)
+          .select(&method(:has_matching_label))
+          .map { |series_info| [series_info['__name__'], true] }
+      end
+      lookup.to_h
+    end
+
+    def has_matching_label(series_info)
+      series_info.has_key?('environment')
+    end
+
+    def metrics_with_series(metric_groups)
+      label_values = client_label_values || []
+
+      metrics = metric_groups.flat_map do |group|
+        group.metrics.map do |metric|
+          matcher = Regexp.compile(metric.detect)
+          [metric, label_values.select(&matcher.method(:match))]
+        end
+      end
+
+      metrics.select { |metric, labels| labels&.any? }
+    end
+  end
+end