Put the correct AzureTags type in StateBag (#10014)

Azure expects the tags format to use a pointer to the string for the map value.
The configuration from the builder is not a pointer so when storing in the state bag for
reference in later execution we convert it when creating the StateBag.

Fixes #10012 and #10013.

* Use the MapToAzureTags helper and error check in resource group creation

* Added test case for tag values not using a pointer

* test/azure/arm: Add test to verify tags stored in state

* test/azure/arm: Add azure_tags to existing acceptance test for Linux

Test Before Fix
```
--- FAIL: TestBuilderAcc_ManagedDisk_Linux (1.81s)
panic: interface conversion: interface {} is map[string]string, not map[string]*string [recovered]
        panic: interface conversion: interface {} is map[string]string, not map[string]*string
FAIL    github.com/hashicorp/packer/builder/azure/arm   1.822s

```

Test After Fix
```
2020/09/29 17:23:03 ui: ==> test: Resource group has been deleted.
--- PASS: TestBuilderAcc_ManagedDisk_Linux (517.41s)
    PASS
    ok      github.com/hashicorp/packer/builder/azure/arm   517.426s
```

Co-authored-by: Wilken Rivera <dev@wilkenrivera.com>

builder/azure/arm/builder.go

@@ -390,7 +390,7 @@ func (b *Builder) getBlobAccount(ctx context.Context, client *AzureClient, resou
 func (b *Builder) configureStateBag(stateBag multistep.StateBag) {
 	stateBag.Put(constants.AuthorizedKey, b.config.sshAuthorizedKey)
 
-	stateBag.Put(constants.ArmTags, b.config.AzureTags)
+	stateBag.Put(constants.ArmTags, packerAzureCommon.MapToAzureTags(b.config.AzureTags))
 	stateBag.Put(constants.ArmComputeName, b.config.tmpComputeName)
 	stateBag.Put(constants.ArmDeploymentName, b.config.tmpDeploymentName)
 

builder/azure/arm/builder_acc_test.go

@@ -223,7 +223,11 @@ const testBuilderAccManagedDiskLinux = `
 	  "image_sku": "16.04-LTS",
 
 	  "location": "South Central US",
-	  "vm_size": "Standard_DS2_v2"
+	  "vm_size": "Standard_DS2_v2",
+	  "azure_tags": {
+	    "env": "testing",
+	    "builder": "packer"
+	   }
 	}]
 }
 `

builder/azure/arm/builder_test.go

@@ -33,3 +33,35 @@ func TestStateBagShouldBePopulatedExpectedValues(t *testing.T) {
 		}
 	}
 }
+
+func TestStateBagShouldPoluateExpectedTags(t *testing.T) {
+	var testSubject Builder
+
+	expectedTags := map[string]string{
+		"env":     "test",
+		"builder": "packer",
+	}
+	armConfig := getArmBuilderConfiguration()
+	armConfig["azure_tags"] = expectedTags
+
+	_, _, err := testSubject.Prepare(armConfig, getPackerConfiguration())
+	if err != nil {
+		t.Fatalf("failed to prepare: %s", err)
+	}
+
+	tags, ok := testSubject.stateBag.Get(constants.ArmTags).(map[string]*string)
+	if !ok {
+		t.Errorf("Expected the builder's state bag to contain tags of type %T, but didn't.", testSubject.config.AzureTags)
+	}
+
+	if len(tags) != len(expectedTags) {
+		t.Errorf("expect tags from state to be the same length as tags from config")
+	}
+
+	for k, v := range tags {
+		if expectedTags[k] != *v {
+			t.Errorf("expect tag value of %s to be %s, but got %s", k, expectedTags[k], *v)
+		}
+	}
+
+}

builder/azure/arm/config_test.go

@@ -2072,8 +2072,8 @@ func TestConfig_PrepareProvidedWinRMPassword(t *testing.T) {
 	}
 }
 
-func getArmBuilderConfiguration() map[string]string {
-	m := make(map[string]string)
+func getArmBuilderConfiguration() map[string]interface{} {
+	m := make(map[string]interface{})
 	for _, v := range requiredConfigValues {
 		m[v] = "ignored00"
 	}

builder/azure/arm/step_create_resource_group.go

@@ -61,7 +61,13 @@ func (s *StepCreateResourceGroup) Run(ctx context.Context, state multistep.State
 
 	var resourceGroupName = state.Get(constants.ArmResourceGroupName).(string)
 	var location = state.Get(constants.ArmLocation).(string)
-	var tags = state.Get(constants.ArmTags).(map[string]*string)
+	tags, ok := state.Get(constants.ArmTags).(map[string]*string)
+	if !ok {
+		err := fmt.Errorf("failed to extract tags from state bag")
+		state.Put(constants.Error, err)
+		s.error(err)
+		return multistep.ActionHalt
+	}
 
 	exists, err := s.exists(ctx, resourceGroupName)
 	if err != nil {

builder/azure/arm/step_create_resource_group_test.go

@@ -220,3 +220,32 @@ func createTestExistingStateBagStepCreateResourceGroup() multistep.StateBag {
 	stateBag.Put(constants.ArmTags, tags)
 	return stateBag
 }
+
+func TestStepCreateResourceGroupShouldFailIfTagsFailCast(t *testing.T) {
+	stateBag := new(multistep.BasicStateBag)
+
+	stateBag.Put(constants.ArmLocation, "Unit Test: Location")
+	stateBag.Put(constants.ArmResourceGroupName, "Unit Test: ResourceGroupName")
+	stateBag.Put(constants.ArmIsExistingResourceGroup, true)
+
+	value := "Unit Test: Tags"
+	tags := map[string]string{
+		"tag01": value,
+	}
+
+	stateBag.Put(constants.ArmTags, tags)
+	var testSubject = &StepCreateResourceGroup{
+		create: func(context.Context, string, string, map[string]*string) error { return nil },
+		say:    func(message string) {},
+		error:  func(e error) {},
+		exists: func(context.Context, string) (bool, error) { return false, nil },
+	}
+	var result = testSubject.Run(context.Background(), stateBag)
+	if result != multistep.ActionHalt {
+		t.Fatalf("Expected the step to return 'ActionHalt', but got '%d'.", result)
+	}
+
+	if _, ok := stateBag.GetOk(constants.Error); ok == false {
+		t.Fatalf("Expected the step to set stateBag['%s'], but it was not.", constants.Error)
+	}
+}