AzureMonitor: Fix custom namespaces (#54937) (#55018)

(cherry picked from commit 879ee82b83)

Co-authored-by: Adam Simpson <adam@adamsimpson.net>

pkg/tsdb/azuremonitor/metrics/azuremonitor-datasource.go

@@ -113,8 +113,13 @@ func (e *AzureMonitorDatasource) buildQueries(queries []backend.DataQuery, dsInf
 		params.Add("timespan", fmt.Sprintf("%v/%v", query.TimeRange.From.UTC().Format(time.RFC3339), query.TimeRange.To.UTC().Format(time.RFC3339)))
 		params.Add("interval", timeGrain)
 		params.Add("aggregation", azJSONModel.Aggregation)
-		params.Add("metricnames", azJSONModel.MetricName) // MetricName or MetricNames ?
-		params.Add("metricnamespace", azJSONModel.MetricNamespace)
+		params.Add("metricnames", azJSONModel.MetricName)
+
+		if azJSONModel.CustomNamespace != "" {
+			params.Add("metricnamespace", azJSONModel.CustomNamespace)
+		} else {
+			params.Add("metricnamespace", azJSONModel.MetricNamespace)
+		}
 
 		// old model
 		dimension := strings.TrimSpace(azJSONModel.Dimension)

pkg/tsdb/azuremonitor/metrics/azuremonitor-datasource_test.go

@@ -250,6 +250,27 @@ func TestAzureMonitorBuildQueries(t *testing.T) {
 	}
 }
 
+func TestCustomNamespace(t *testing.T) {
+	datasource := &AzureMonitorDatasource{}
+
+	t.Run("it should set the metricNamespace to a customNamespace value if customNamespace is present as a parameter", func(t *testing.T) {
+		q := []backend.DataQuery{
+			{
+				JSON: []byte(`{
+							"azureMonitor": {
+								"customNamespace": "custom/namespace"						
+							}
+						}`),
+			},
+		}
+
+		result, err := datasource.buildQueries(q, types.DatasourceInfo{})
+		require.NoError(t, err)
+		expected := "custom/namespace"
+		require.Equal(t, expected, result[0].Params.Get("metricnamespace"))
+	})
+}
+
 func makeDates(startDate time.Time, count int, interval time.Duration) (times []time.Time) {
 	for i := 0; i < count; i++ {
 		times = append(times, startDate.Add(interval*time.Duration(i)))

pkg/tsdb/azuremonitor/types/types.go

@@ -115,6 +115,7 @@ type AzureMonitorJSONQuery struct {
 		ResourceURI string `json:"resourceUri"`
 		// These are used to reconstruct a resource URI
 		MetricNamespace string `json:"metricNamespace"`
+		CustomNamespace string `json:"customNamespace"`
 		MetricName      string `json:"metricName"`
 		ResourceGroup   string `json:"resourceGroup"`
 		ResourceName    string `json:"resourceName"`