Implement cloud config parser and writer methods

Author: Danil-Grigorev

pkg/render/render.go

@@ -20,8 +20,10 @@ import (
 )
 
 const (
+	configDataKey      = "cloud.conf"
 	bootstrapNamespace = "kube-system"
 	bootstrapPrefix    = "bootstrap"
+	configPrefix       = "config"
 	// bootstrapFileName is built from bootstrapPrefix, resource name and kind
 	bootstrapFileName = "%s/%s-%s.yaml"
 )
@@ -49,7 +51,7 @@ func New(infrastructureFile, imagesFile, cloudConfigFile string) *Render {
 // Run runs boostrap for Machine Config Controller
 // It writes all the assets to destDir
 func (r *Render) Run(destinationDir string) error {
-	infra, imagesMap, err := r.readAssets()
+	infra, imagesMap, cloudConfig, err := r.readAssets()
 	if err != nil {
 		klog.Errorf("Cannot read assets from provided paths: %v", err)
 		return err
@@ -67,36 +69,51 @@ func (r *Render) Run(destinationDir string) error {
 		klog.Infof("Collected resource %s %q successfully", resource.GetObjectKind().GroupVersionKind(), client.ObjectKeyFromObject(resource))
 	}
 
-	return writeAssets(destinationDir, resources)
+	if err := writeAssets(destinationDir, resources); err != nil {
+		klog.Errorf("Could not write assets to bootstrap dir: %v", err)
+		return err
+	}
+
+	return writeCloudConfig(destinationDir, cloudConfig)
 }
 
 // readAssets collects infrastructure resource and images config map from provided paths
-func (r *Render) readAssets() (*configv1.Infrastructure, *corev1.ConfigMap, error) {
+func (r *Render) readAssets() (*configv1.Infrastructure, *corev1.ConfigMap, string, error) {
 	infraData, err := ioutil.ReadFile(r.infrastructureFile)
 	if err != nil {
 		klog.Errorf("Unable to read data from %q: %v", r.infrastructureFile, err)
-		return nil, nil, err
+		return nil, nil, "", err
 	}
 
 	infra := &configv1.Infrastructure{}
 	if err := yaml.UnmarshalStrict(infraData, infra); err != nil {
 		klog.Errorf("Cannot decode data into configv1.Infrastructure from %q: %v", r.infrastructureFile, err)
-		return nil, nil, err
+		return nil, nil, "", err
 	}
 
 	imagesData, err := ioutil.ReadFile(r.imagesFile)
 	if err != nil {
 		klog.Errorf("Unable to read data from %q: %v", r.imagesFile, err)
-		return nil, nil, err
+		return nil, nil, "", err
 	}
 
 	imagesConfigMap := &corev1.ConfigMap{}
 	if err := yaml.UnmarshalStrict(imagesData, imagesConfigMap); err != nil {
 		klog.Errorf("Cannot decode data into v1.ConfigMap from %q: %v", r.imagesFile, err)
-		return nil, nil, err
+		return nil, nil, "", err
+	}
+
+	cloudConfig := ""
+	// if the cloudConfig is set in infra read the cloudConfigFile
+	if infra.Spec.CloudConfig.Name != "" {
+		cloudConfig, err = loadBootstrapCloudProviderConfig(infra, r.cloudConfigFile)
+		if err != nil {
+			klog.Errorf("failed to load the cloud provider config: %v", err)
+			return nil, nil, "", err
+		}
 	}
 
-	return infra, imagesConfigMap, nil
+	return infra, imagesConfigMap, cloudConfig, nil
 }
 
 // writeAssets writes static pods to disk into <destinationDir>/<bootstrapPrefix>/<resourceName>-<resourceKind>.yaml
@@ -122,5 +139,48 @@ func writeAssets(destinationDir string, resources []client.Object) error {
 			return err
 		}
 	}
+
+	return nil
+}
+
+// writeCloudConfig creates config folder and writes resources such as cloud-config file
+// for use in bootstrap
+func writeCloudConfig(destinationDir string, cloudConfig string) error {
+	// Create config directory in advance to ensure it is present for any provider
+	configDir := filepath.Join(destinationDir, configPrefix)
+	if err := os.MkdirAll(configDir, fs.ModePerm); err != nil {
+		klog.Errorf("Unable to create destination dir %q: %v", configDir, err)
+		return err
+	}
+
+	if cloudConfig != "" {
+		cloudConfigFile := filepath.Join(configDir, configDataKey)
+
+		klog.Infof("Writing cloud config on disk in %q", cloudConfigFile)
+		err := os.WriteFile(cloudConfigFile, []byte(cloudConfig), 0666)
+		if err != nil {
+			klog.Errorf("Failed to write cloud config to disk in %q: %v", cloudConfigFile, err)
+			return err
+		}
+	}
+
 	return nil
 }
+
+// loadBootstrapCloudProviderConfig reads the cloud provider config from cloudConfigFile based on infra object.
+func loadBootstrapCloudProviderConfig(infra *configv1.Infrastructure, cloudConfigFile string) (string, error) {
+	data, err := os.ReadFile(cloudConfigFile)
+	if err != nil {
+		return "", err
+	}
+	cloudConfigMap := &corev1.ConfigMap{}
+	if err := yaml.UnmarshalStrict(data, cloudConfigMap); err != nil {
+		return "", err
+	}
+	cloudConf, ok := cloudConfigMap.Data[configDataKey]
+	if !ok {
+		klog.Infof("falling back to reading cloud provider config from user specified key %s", infra.Spec.CloudConfig.Key)
+		cloudConf = cloudConfigMap.Data[infra.Spec.CloudConfig.Key]
+	}
+	return cloudConf, nil
+}