telmetry: add databroker storage metrics and tracing (#1161)

* telmetry: add databroker storage metrics and tracing

internal/telemetry/metrics/storage_test.go

@@ -0,0 +1,33 @@
+package metrics
+
+import (
+	"context"
+	"errors"
+	"testing"
+	"time"
+
+	"go.opencensus.io/stats/view"
+)
+
+func Test_RecordStorageOperation(t *testing.T) {
+
+	tests := []struct {
+		name     string
+		tags     *StorageOperationTags
+		duration time.Duration
+		want     string
+	}{
+		{"success", &StorageOperationTags{Operation: "test", Backend: "testengine"}, time.Millisecond * 5, "{ { {backend testengine}{operation test}{result success}{service databroker} }&{1 5 5 5 0"},
+		{"error", &StorageOperationTags{Operation: "failtest", Backend: "failengine", Error: errors.New("failure")}, time.Millisecond * 5, "{ { {backend failengine}{operation failtest}{result error}{service databroker} }&{1 5 5 5 0"},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			view.Unregister(StorageViews...)
+			view.Register(StorageViews...)
+			RecordStorageOperation(context.Background(), tt.tags, tt.duration)
+
+			testDataRetrieval(StorageOperationDurationView, t, tt.want)
+		})
+	}
+}