Harmonize metric label names to controllerring (#439)

* Harmonize metric label names to `controllerring`

* Extract const for metrics namespace

docs/monitoring.md

@@ -33,7 +33,7 @@ This doesn't consider the action taken by the shard.
 #### `controller_sharding_ring_calculations_total`
 
 Type: counter  
-Description: Total number of shard ring calculations per `ControllerRing`.
+Description: Total number of hash ring calculations per `ControllerRing`.
 This counter is incremented every time the sharder calculates a new consistent hash ring based on the shard leases.
 
 ## sharding-exporter

pkg/sharding/metrics/metrics.go

@@ -22,38 +22,44 @@ import (
 	"sigs.k8s.io/controller-runtime/pkg/metrics"
 )
 
+const Namespace = "controller_sharding"
+
 var (
 	// AssignmentsTotal is a prometheus counter metric which holds the total number of shard assignments by the sharder
-	// webhook per Ring and GroupResource.
+	// webhook per ControllerRing and GroupResource.
 	// It has a label which refers to the ControllerRing and two labels which refer to the object's GroupResource.
 	AssignmentsTotal = prometheus.NewCounterVec(prometheus.CounterOpts{
-		Name: "controller_sharding_assignments_total",
-		Help: "Total number of shard assignments by the sharder webhook per Ring and GroupResource",
-	}, []string{"ringName", "group", "resource"})
+		Namespace: Namespace,
+		Name:      "assignments_total",
+		Help:      "Total number of shard assignments by the sharder webhook per ControllerRing and GroupResource",
+	}, []string{"controllerring", "group", "resource"})
 
 	// MovementsTotal is a prometheus counter metric which holds the total number of shard movements triggered by the
-	// sharder controller per Ring and GroupResource.
+	// sharder controller per ControllerRing and GroupResource.
 	// It has a label which refers to the ControllerRing and two labels which refer to the object's GroupResource.
 	MovementsTotal = prometheus.NewCounterVec(prometheus.CounterOpts{
-		Name: "controller_sharding_movements_total",
-		Help: "Total number of shard movements triggered by the sharder controller per Ring and GroupResource",
-	}, []string{"ringName", "group", "resource"})
+		Namespace: Namespace,
+		Name:      "movements_total",
+		Help:      "Total number of shard movements triggered by the sharder controller per ControllerRing and GroupResource",
+	}, []string{"controllerring", "group", "resource"})
 
 	// DrainsTotal is a prometheus counter metric which holds the total number of shard drains triggered by the sharder
-	// controller per Ring and GroupResource.
+	// controller per ControllerRing and GroupResource.
 	// It has a label which refers to the ControllerRing and two labels which refer to the object's GroupResource.
 	DrainsTotal = prometheus.NewCounterVec(prometheus.CounterOpts{
-		Name: "controller_sharding_drains_total",
-		Help: "Total number of shard drains triggered by the sharder controller per Ring and GroupResource",
-	}, []string{"ringName", "group", "resource"})
+		Namespace: Namespace,
+		Name:      "drains_total",
+		Help:      "Total number of shard drains triggered by the sharder controller per ControllerRing and GroupResource",
+	}, []string{"controllerring", "group", "resource"})
 
 	// RingCalculationsTotal is a prometheus counter metric which holds the total
-	// number of shard ring calculations per ring kind.
+	// number of hash ring calculations per ControllerRing.
 	// It has a label which refers to the ControllerRing.
 	RingCalculationsTotal = prometheus.NewCounterVec(prometheus.CounterOpts{
-		Name: "controller_sharding_ring_calculations_total",
-		Help: "Total number of shard ring calculations per ring kind",
-	}, []string{"name"})
+		Namespace: Namespace,
+		Name:      "ring_calculations_total",
+		Help:      "Total number of hash ring calculations per ControllerRing",
+	}, []string{"controllerring"})
 )
 
 func init() {