AzureMonitor: Fix out of bounds error when accessing metricNamespaceArray and resourceNameArray in buildResourceURI (#89222)

Fix out of range error when accessing metricNamespaceArray in buildResourceURI

Author: adamyeats

pkg/tsdb/azuremonitor/metrics/url-builder.go

@@ -39,12 +39,19 @@ func (params *urlBuilder) buildResourceURI() (*string, error) {
 	}
 
 	metricNamespaceArray := strings.Split(*metricNamespace, "/")
+
+	provider := ""
+	if len(metricNamespaceArray) > 1 {
+		provider = metricNamespaceArray[0]
+		metricNamespaceArray = metricNamespaceArray[1:]
+	} else {
+		return nil, fmt.Errorf("metricNamespace is not in the correct format")
+	}
+
 	var resourceNameArray []string
 	if params.ResourceName != nil && *params.ResourceName != "" {
 		resourceNameArray = strings.Split(*params.ResourceName, "/")
 	}
-	provider := metricNamespaceArray[0]
-	metricNamespaceArray = metricNamespaceArray[1:]
 
 	if strings.HasPrefix(strings.ToLower(*metricNamespace), "microsoft.storage/storageaccounts/") &&
 		params.ResourceName != nil &&
@@ -66,7 +73,11 @@ func (params *urlBuilder) buildResourceURI() (*string, error) {
 	}
 
 	for i, namespace := range metricNamespaceArray {
-		urlArray = append(urlArray, namespace, resourceNameArray[i])
+		if i < len(resourceNameArray) {
+			urlArray = append(urlArray, namespace, resourceNameArray[i])
+		} else {
+			return nil, fmt.Errorf("resourceNameArray does not have enough elements")
+		}
 	}
 
 	resourceURI := strings.Join(urlArray, "/")

pkg/tsdb/azuremonitor/metrics/url-builder_test.go

@@ -1,6 +1,7 @@
 package metrics
 
 import (
+	"strings"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -145,5 +146,62 @@ func TestBuildResourceURI(t *testing.T) {
 				}
 			}
 		})
+
+		t.Run("provider extraction from metricNamespaceArray", func(t *testing.T) {
+			ub := &urlBuilder{
+				DefaultSubscription: strPtr("default-sub"),
+				MetricNamespace:     strPtr("provider1/service1"),
+				ResourceGroup:       strPtr("rg"),
+				ResourceName:        strPtr("rn1/rn2/rn3"),
+			}
+			expectedProvider := "provider1"
+
+			uri, err := ub.buildResourceURI()
+			if err != nil {
+				t.Errorf("Unexpected error: %v", err)
+			}
+			if uri == nil {
+				t.Fatalf("Expected non-nil uri")
+			}
+			if !strings.Contains(*uri, expectedProvider) {
+				t.Errorf("Expected provider %v in uri %v", expectedProvider, *uri)
+			}
+		})
+
+		t.Run("when metricNamespace is not in the correct format", func(t *testing.T) {
+			ub := &urlBuilder{
+				DefaultSubscription: strPtr("default-sub"),
+				MetricNamespace:     strPtr("invalidformat"),
+			}
+
+			_, err := ub.buildResourceURI()
+			if err == nil || err.Error() != "metricNamespace is not in the correct format" {
+				t.Errorf("Expected error: metricNamespace is not in the correct format")
+			}
+		})
+
+		t.Run("when resourceNameArray index out of range", func(t *testing.T) {
+			ub := &urlBuilder{
+				DefaultSubscription: strPtr("default-sub"),
+				MetricNamespace:     strPtr("provider1/service1"),
+				ResourceName:        strPtr("rn1/rn2/rn3"),
+			}
+
+			_, err := ub.buildResourceURI()
+			if err != nil {
+				t.Errorf("Unexpected error: %v", err)
+			}
+
+			ub = &urlBuilder{
+				DefaultSubscription: strPtr("default-sub"),
+				MetricNamespace:     strPtr("provider1/service1/service2"),
+				ResourceName:        strPtr(""),
+			}
+
+			_, err = ub.buildResourceURI()
+			if err == nil || err.Error() != "resourceNameArray does not have enough elements" {
+				t.Errorf("Expected error: resourceNameArray does not have enough elements")
+			}
+		})
 	})
 }