Fixing panic issue in Validate when properties are nil

pkg/acsengine/testdata/v20170701/cs-without-properties.json

@@ -0,0 +1,6 @@
+{
+  "type": "Microsoft.ContainerService/managedClusters",
+  "name": "[parameters('clusterName')]",
+  "apiVersion": "2017-07-01",
+  "location": "[resourceGroup().location]"
+}

pkg/api/apiloader.go

@@ -6,6 +6,7 @@ import (
 	"io/ioutil"
 	"reflect"
 
+	"fmt"
 	"github.com/Azure/acs-engine/pkg/api/agentPoolOnlyApi/v20170831"
 	"github.com/Azure/acs-engine/pkg/api/agentPoolOnlyApi/v20180331"
 	apvlabs "github.com/Azure/acs-engine/pkg/api/agentPoolOnlyApi/vlabs"
@@ -82,6 +83,9 @@ func (a *Apiloader) LoadContainerService(
 			}
 		}
 		setContainerServiceDefaultsv20160930(containerService)
+		if containerService.Properties == nil {
+			return nil, fmt.Errorf("missing ContainerService Properties")
+		}
 		if e := containerService.Properties.Validate(); validate && e != nil {
 			return nil, e
 		}
@@ -102,6 +106,9 @@ func (a *Apiloader) LoadContainerService(
 			}
 		}
 		setContainerServiceDefaultsv20160330(containerService)
+		if containerService.Properties == nil {
+			return nil, fmt.Errorf("missing ContainerService Properties")
+		}
 		if e := containerService.Properties.Validate(); validate && e != nil {
 			return nil, e
 		}
@@ -123,6 +130,9 @@ func (a *Apiloader) LoadContainerService(
 			}
 		}
 		setContainerServiceDefaultsv20170131(containerService)
+		if containerService.Properties == nil {
+			return nil, fmt.Errorf("missing ContainerService Properties")
+		}
 		if e := containerService.Properties.Validate(); validate && e != nil {
 			return nil, e
 		}
@@ -143,6 +153,9 @@ func (a *Apiloader) LoadContainerService(
 				return nil, e
 			}
 		}
+		if containerService.Properties == nil {
+			return nil, fmt.Errorf("missing ContainerService Properties")
+		}
 		if e := containerService.Properties.Validate(isUpdate); validate && e != nil {
 			return nil, e
 		}
@@ -168,6 +181,9 @@ func (a *Apiloader) LoadContainerService(
 				return nil, e
 			}
 		}
+		if containerService.Properties == nil {
+			return nil, fmt.Errorf("missing ContainerService Properties")
+		}
 		if e := containerService.Properties.Validate(isUpdate); validate && e != nil {
 			return nil, e
 		}

pkg/api/apiloader_test.go

@@ -85,3 +85,17 @@ func TestLoadContainerServiceFromFile(t *testing.T) {
 		t.Errorf("Failed to set orcherstator version to windows default when it is not set in the json API v20170131, got %s but expected %s", containerService.Properties.OrchestratorProfile.OrchestratorVersion, common.GetDefaultKubernetesVersionWindows())
 	}
 }
+
+func TestLoadContainerServiceWithNilProperties(t *testing.T) {
+	apiloader := &Apiloader{}
+	existingContainerService := &ContainerService{Name: "test",
+		Properties: &Properties{OrchestratorProfile: &OrchestratorProfile{OrchestratorType: Kubernetes, OrchestratorVersion: "1.6.9"}}}
+	_, _, err := apiloader.LoadContainerServiceFromFile("../acsengine/testdata/v20170701/cs-without-properties.json", true, false, existingContainerService)
+	if err == nil {
+		t.Errorf("Expected error to be thrown")
+	}
+	expectedMsg := "missing ContainerService Properties"
+	if err.Error() != expectedMsg {
+		t.Errorf("Expected error with message %s but got %s", expectedMsg, err.Error())
+	}
+}

pkg/api/vlabs/validate.go

@@ -96,6 +96,9 @@ func init() {
 
 // Validate implements APIObject
 func (a *Properties) Validate(isUpdate bool) error {
+	if a == nil {
+		return fmt.Errorf("missing ContainerService Properties")
+	}
 	if e := validate.Struct(a); e != nil {
 		return handleValidationErrors(e.(validator.ValidationErrors))
 	}

pkg/api/vlabs/validate_test.go

@@ -852,6 +852,15 @@ func Test_Properties_ValidateAddons(t *testing.T) {
 	}
 }
 
+func TestPropertiesValidationNil(t *testing.T) {
+	containerService := &ContainerService{}
+	err := containerService.Properties.Validate(true)
+	expected := "missing ContainerService Properties"
+	if err == nil || err.Error() != expected {
+		t.Errorf("Expected error with message %s", expected)
+	}
+}
+
 func TestWindowsVersions(t *testing.T) {
 	for _, version := range common.GetAllSupportedKubernetesVersionsWindows() {
 		p := getK8sDefaultProperties(true)