fix: custom_labels on SidekiqStatsCollector

Author: mbarany

lib/prometheus_exporter/server/sidekiq_stats_collector.rb

@@ -30,11 +30,12 @@ def metrics
       SIDEKIQ_STATS_GAUGES.each_key { |name| gauges[name]&.reset! }
 
       sidekiq_metrics.map do |metric|
+        labels = metric.fetch("custom_labels", {})
         SIDEKIQ_STATS_GAUGES.map do |name, help|
           if (value = metric["stats"][name])
             gauge =
               gauges[name] ||= PrometheusExporter::Metric::Gauge.new("sidekiq_stats_#{name}", help)
-            gauge.observe(value)
+            gauge.observe(value, labels)
           end
         end
       end

test/server/sidekiq_stats_collector_test.rb

@@ -39,6 +39,38 @@ def test_collecting_metrics
     assert_equal expected, metrics.map(&:metric_text)
   end
 
+  def test_collecting_metrics_with_custom_labels
+    collector.collect(
+      "stats" => {
+        "dead_size" => 1,
+        "enqueued" => 2,
+        "failed" => 3,
+        "processed" => 4,
+        "processes_size" => 5,
+        "retry_size" => 6,
+        "scheduled_size" => 7,
+        "workers_size" => 8,
+      },
+      "custom_labels" => {
+        "service" => "test",
+        "foo" => "bar",
+      },
+    )
+
+    metrics = collector.metrics
+    expected = [
+      "sidekiq_stats_dead_size{service=\"test\",foo=\"bar\"} 1",
+      "sidekiq_stats_enqueued{service=\"test\",foo=\"bar\"} 2",
+      "sidekiq_stats_failed{service=\"test\",foo=\"bar\"} 3",
+      "sidekiq_stats_processed{service=\"test\",foo=\"bar\"} 4",
+      "sidekiq_stats_processes_size{service=\"test\",foo=\"bar\"} 5",
+      "sidekiq_stats_retry_size{service=\"test\",foo=\"bar\"} 6",
+      "sidekiq_stats_scheduled_size{service=\"test\",foo=\"bar\"} 7",
+      "sidekiq_stats_workers_size{service=\"test\",foo=\"bar\"} 8",
+    ]
+    assert_equal expected, metrics.map(&:metric_text)
+  end
+
   def test_only_fresh_metrics_are_collected
     stub_monotonic_clock(1.0) do
       collector.collect(