fix: Service entities tagged with multiple keptn_service tags should produce an error

internal/onboard/service_sync.go

@@ -212,14 +212,20 @@ func (s *serviceSynchronizer) fetchExistingServices() error {
 }
 
 func getKeptnServiceName(entity dynatrace.Entity) (string, error) {
-	if entity.Tags != nil {
-		for _, tag := range entity.Tags {
-			if tag.Key == "keptn_service" && tag.Value != "" {
-				return tag.Value, nil
-			}
+	serviceTags := make([]string, 0)
+	for _, tag := range entity.Tags {
+		if tag.Key == "keptn_service" && tag.Value != "" {
+			serviceTags = append(serviceTags, tag.Value)
 		}
 	}
-	return "", fmt.Errorf("entity %v has no 'keptn_service' tag", entity.EntityID)
+	if len(serviceTags) == 0 {
+		return "", fmt.Errorf("entity %v has no valid 'keptn_service' tag", entity.EntityID)
+	}
+	if len(serviceTags) > 1 {
+		return "", fmt.Errorf("entity %v has multiple 'keptn_service' tags", entity.EntityID)
+	}
+
+	return serviceTags[0], nil
 }
 
 func doesServiceExist(services []string, serviceName string) bool {

internal/onboard/service_sync_test.go

@@ -474,7 +474,6 @@ func Test_getKeptnServiceName(t *testing.T) {
 					Tags:        nil,
 				},
 			},
-			want:    "",
 			wantErr: true,
 		},
 		{
@@ -496,16 +495,57 @@ func Test_getKeptnServiceName(t *testing.T) {
 			want:    "my-service",
 			wantErr: false,
 		},
+		{
+			name: "keptn_service tag with no value",
+			args: args{
+				entity: dynatrace.Entity{
+					EntityID:    "entity-id",
+					DisplayName: ":10999",
+					Tags: []dynatrace.Tag{
+						{
+							Context:              "CONTEXTLESS",
+							Key:                  "keptn_service",
+							StringRepresentation: "keptn_service",
+						},
+					},
+				},
+			},
+			wantErr: true,
+		},
+		{
+			name: "two keptn_service tags",
+			args: args{
+				entity: dynatrace.Entity{
+					EntityID:    "entity-id",
+					DisplayName: ":10999",
+					Tags: []dynatrace.Tag{
+						{
+							Context:              "CONTEXTLESS",
+							Key:                  "keptn_service",
+							StringRepresentation: "keptn_service:value1",
+							Value:                "value1",
+						},
+						{
+							Context:              "CONTEXTLESS",
+							Key:                  "keptn_service",
+							StringRepresentation: "keptn_service:value2",
+							Value:                "value2",
+						},
+					},
+				},
+			},
+			wantErr: true,
+		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			got, err := getKeptnServiceName(tt.args.entity)
-			if (err != nil) != tt.wantErr {
-				t.Errorf("getKeptnServiceName() error = %v, wantErr %v", err, tt.wantErr)
-				return
-			}
-			if got != tt.want {
-				t.Errorf("getKeptnServiceName() = %v, want %v", got, tt.want)
+
+			if tt.wantErr {
+				assert.Error(t, err)
+			} else {
+				assert.NoError(t, err)
+				assert.EqualValues(t, tt.want, got)
 			}
 		})
 	}