controllers: report StorageSystem metrics

transforming StorageSystem spec into metrics so that we can
use Prometheus queries to understand object relationships.

Signed-off-by: Umanga Chapagain <[email protected]>

controllers/storagesystem_controller.go

@@ -33,6 +33,7 @@ import (
 
 	operatorv1alpha1 "github.com/operator-framework/api/pkg/operators/v1alpha1"
 	odfv1alpha1 "github.com/red-hat-data-services/odf-operator/api/v1alpha1"
+	"github.com/red-hat-data-services/odf-operator/metrics"
 	"github.com/red-hat-data-services/odf-operator/pkg/util"
 )
 
@@ -76,6 +77,8 @@ func (r *StorageSystemReconciler) Reconcile(ctx context.Context, req ctrl.Reques
 
 	logger.Info("storagesystem instance found")
 
+	metrics.ReportODFSystemMapMetrics(instance.Name, instance.Spec.Name, instance.Spec.Namespace, string(instance.Spec.Kind))
+
 	if err := r.validateStorageSystemSpec(instance, logger); err != nil {
 		logger.Error(err, "failed to validate storagesystem")
 		return reconcile.Result{}, err

metrics/metrics.go

@@ -0,0 +1,44 @@
+/*
+Copyright 2021 Red Hat OpenShift Data Foundation.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package metrics
+
+import (
+	"github.com/prometheus/client_golang/prometheus"
+	"sigs.k8s.io/controller-runtime/pkg/metrics"
+)
+
+var (
+	storageSystemMap = prometheus.NewGaugeVec(prometheus.GaugeOpts{
+		Namespace: "odf",
+		Subsystem: "",
+		Name:      "system_map",
+		Help:      "Map of ODF StorageSystems to their target Custom Resource",
+	}, []string{"storage_system", "target_name", "target_namespace", "target_kind"})
+)
+
+func init() {
+	metrics.Registry.MustRegister(storageSystemMap)
+}
+
+func ReportODFSystemMapMetrics(storageSystem, name, namespace, kind string) {
+	storageSystemMap.With(prometheus.Labels{
+		"storage_system":   storageSystem,
+		"target_name":      name,
+		"target_namespace": namespace,
+		"target_kind":      kind,
+	}).Set(1)
+}

metrics/metrics_test.go

@@ -0,0 +1,68 @@
+/*
+Copyright 2021 Red Hat OpenShift Data Foundation.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package metrics
+
+import (
+	"testing"
+
+	"github.com/prometheus/client_golang/prometheus/testutil"
+	"github.com/stretchr/testify/assert"
+	"sigs.k8s.io/controller-runtime/pkg/metrics"
+)
+
+var defaultRegistry = metrics.Registry
+var find string = "odf_system_map"
+
+func TestReportODFSystemMapMetrics(t *testing.T) {
+	type args struct {
+		storageSystem, name, namespace, kind string
+	}
+	tests := []struct {
+		name string
+		args args
+	}{
+		{
+			name: "StorageSystem to StorageCluster",
+			args: args{
+				storageSystem: "StorageSystem1",
+				name:          "StorageCluster1",
+				namespace:     "Namespace1",
+				kind:          "StorageCluster",
+			},
+		},
+		{
+			name: "StorageSystem to Flashsystem",
+			args: args{
+				storageSystem: "StorageSystem2",
+				name:          "FlashSystem1",
+				namespace:     "Namespace1",
+				kind:          "Flashsystem",
+			},
+		},
+	}
+	for n, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			ReportODFSystemMapMetrics(tt.args.storageSystem, tt.args.name, tt.args.namespace, tt.args.kind)
+			count, err := testutil.GatherAndCount(defaultRegistry, find)
+			assert.NoError(t, err)
+			assert.Equal(t, n+1, count)
+			problems, err := testutil.GatherAndLint(defaultRegistry, find)
+			assert.NoError(t, err)
+			assert.Equal(t, 0, len(problems))
+		})
+	}
+}