Track the number of steps created

src/hydra-queue-runner/hydra-queue-runner.cc

@@ -54,6 +54,13 @@ State::PromMetrics::PromMetrics()
             .Register(*registry)
             .Add({})
     )
+    , queue_steps_created(
+        prometheus::BuildCounter()
+            .Name("hydraqueuerunner_queue_steps_created_total")
+            .Help("Number of steps created")
+            .Register(*registry)
+            .Add({})
+    )
     , queue_checks_early_exits(
         prometheus::BuildCounter()
             .Name("hydraqueuerunner_queue_checks_early_exits_total")

src/hydra-queue-runner/queue-monitor.cc

@@ -448,6 +448,8 @@ Step::ptr State::createStep(ref<Store> destStore,
 
     if (!isNew) return step;
 
+    prom.queue_steps_created.Increment();
+
     printMsg(lvlDebug, "considering derivation ‘%1%’", localStore->printStorePath(drvPath));
 
     /* Initialize the step. Note that the step may be visible in

src/hydra-queue-runner/state.hh

@@ -444,6 +444,7 @@ private:
 
         prometheus::Counter& queue_checks_started;
         prometheus::Counter& queue_build_loads;
+        prometheus::Counter& queue_steps_created;
         prometheus::Counter& queue_checks_early_exits;
         prometheus::Counter& queue_checks_finished;
         prometheus::Gauge& queue_max_id;