Add metrics for cached queries + cache hit/miss

monitoring/defaults.go

@@ -5,6 +5,9 @@ func (ms *MetricsSetup) RegisterDefaultMetrics() {
 	ms.RegisterMetricsCounter(MetricsFailed, nil)
 	ms.RegisterMetricsCounter(MetricsSkipped, nil)
 	ms.RegisterMetricsHistogram(MetricsDuration, nil)
+	ms.RegisterMetricsCounter(MetricsCacheHit, nil)
+	ms.RegisterMetricsCounter(MetricsCacheMiss, nil)
+	ms.RegisterMetricsCounter(MetricsQueriesCached, nil)
 }
 
 func (ms *MetricsSetup) RegisterGoMetrics() {

monitoring/structs.go

@@ -7,4 +7,8 @@ const (
 	MetricsSkipped       = "requests_skipped"
 	MetricsExecutedQuery = "executed_query"
 	MetricsTimedQuery    = "timed_query"
+
+	MetricsCacheHit      = "cache_hit"
+	MetricsCacheMiss     = "cache_miss"
+	MetricsQueriesCached = "cached_queries"
 )