Updates Azure CloudConfigTransformer to set cloud

This change adds the functionality from the cluster-config-operator
azure CloudConfigTransformer.

The functionality we bring over is:

1. Ensure that the Cloud is set in the cloud.conf
   i. If it is set, verify that it is valid and does not conflict with the
      infrastructure config. If it conflicts, we want to error
  ii. If it is not set, default to public cloud (configv1.AzurePublicCloud)

 2. Verify the cloud name set in the infra config is valid, if it is not
 bail with an informative error

See openshift/cluster-config-operator#133 for
the PR that initially added this functionality.

Author: theobarberbany

pkg/cloud/azure/azure.go

@@ -4,10 +4,12 @@ import (
 	"embed"
 	"encoding/json"
 	"fmt"
+	"strings"
 
 	"github.com/asaskevich/govalidator"
 	configv1 "github.com/openshift/api/config/v1"
 	appsv1 "k8s.io/api/apps/v1"
+	"k8s.io/apimachinery/pkg/util/validation/field"
 	"sigs.k8s.io/controller-runtime/pkg/client"
 
 	azureconsts "sigs.k8s.io/cloud-provider-azure/pkg/consts"
@@ -28,6 +30,24 @@ var (
 	}
 )
 
+var (
+	validAzureCloudNames = map[configv1.AzureCloudEnvironment]bool{
+		configv1.AzurePublicCloud:       true,
+		configv1.AzureUSGovernmentCloud: true,
+		configv1.AzureChinaCloud:        true,
+		configv1.AzureGermanCloud:       true,
+		configv1.AzureStackCloud:        true,
+	}
+
+	validAzureCloudNameValues = func() []string {
+		v := make([]string, 0, len(validAzureCloudNames))
+		for n := range validAzureCloudNames {
+			v = append(v, string(n))
+		}
+		return v
+	}()
+)
+
 type imagesReference struct {
 	CloudControllerManager         string `valid:"required"`
 	CloudControllerManagerOperator string `valid:"required"`
@@ -91,12 +111,60 @@ func NewProviderAssets(config config.OperatorConfig) (common.CloudProviderAssets
 	return assets, nil
 }
 
+func IsAzure(infra *configv1.Infrastructure) bool {
+	if infra.Status.PlatformStatus != nil &&
+		infra.Status.PlatformStatus.Type == configv1.AzurePlatformType {
+		return true
+	}
+	return false
+}
+
 func CloudConfigTransformer(source string, infra *configv1.Infrastructure, network *configv1.Network) (string, error) {
+	if !IsAzure(infra) {
+		return "", fmt.Errorf("invalid platform, expected to be Azure")
+	}
+
 	var cfg azure.Config
 	if err := json.Unmarshal([]byte(source), &cfg); err != nil {
 		return "", fmt.Errorf("failed to unmarshal the cloud.conf: %w", err)
 	}
 
+	// We are copying the behaviour from CCO's transformer we need to:
+	// 1. Ensure that the Cloud is set in the cloud.conf
+	//   i. If it is set, verify that it is valid and does not conflict with the
+	//      infrastructure config. If it conflicts, we want to error
+	//  ii. If it is not set, default to public cloud (configv1.AzurePublicCloud)
+	//
+	// 2. Verify the cloud name set in the infra config is valid, if it is not
+	// bail with an informative error
+
+	// Verify the cloud name set in the infra config is valid
+	cloud := configv1.AzurePublicCloud
+	if azurePlatform := infra.Status.PlatformStatus.Azure; azurePlatform != nil {
+		if c := azurePlatform.CloudName; c != "" {
+			if !validAzureCloudNames[c] {
+				return "", field.NotSupported(field.NewPath("status", "platformStatus", "azure", "cloudName"), c, validAzureCloudNameValues)
+			}
+			cloud = c
+		}
+	}
+
+	// Ensure Cloud is set in cloud.conf matches what is set in infra
+	if cfg.Cloud != "" {
+		if !strings.EqualFold(string(cloud), cfg.Cloud) {
+			return "",
+				fmt.Errorf(`invalid user-provided cloud.conf: \"cloud\" field in user-provided
+				cloud.conf conflicts with infrastructure object`)
+		}
+	}
+
+	// TODO: Remove when you work this out (before merging)
+	// Why is cfg.Cloud not typed: type AzureCloudEnvironment string
+
+	// At this point these should always be the same
+	// comparrison
+	cfg.Cloud = string(cloud)
+
 	// If the virtual machine type is not set we need to make sure it uses the
 	// "standard" instance type. See OCPBUGS-25483 and OCPBUGS-20213 for more
 	// information