✨clusterctl: add support for local override of files read from provider's repository

cmd/clusterctl/pkg/client/config/reader_viper.go

@@ -26,6 +26,9 @@ import (
 	"k8s.io/klog"
 )
 
+// ConfigFolder defines the name of the config folder under $home
+const ConfigFolder = "cluster-api"
+
 // viperReader implements Reader using viper as backend for reading from environment variables
 // and from a clusterctl config file.
 type viperReader struct {
@@ -44,7 +47,7 @@ func (v *viperReader) Init(path string) error {
 	} else {
 		// Configure for searching cluster-api/.clusterctl{.extension} in home directory
 		viper.SetConfigName(".clusterctl")
-		viper.AddConfigPath(filepath.Join(homedir.HomeDir(), "cluster-api"))
+		viper.AddConfigPath(filepath.Join(homedir.HomeDir(), ConfigFolder))
 	}
 
 	// Configure for reading environment variables as well, and more specifically:

cmd/clusterctl/pkg/client/repository/client.go

@@ -17,9 +17,13 @@ limitations under the License.
 package repository
 
 import (
+	"io/ioutil"
 	"net/url"
+	"os"
+	"path/filepath"
 
 	"github.com/pkg/errors"
+	"k8s.io/client-go/util/homedir"
 	"sigs.k8s.io/cluster-api/cmd/clusterctl/pkg/client/config"
 	"sigs.k8s.io/cluster-api/cmd/clusterctl/pkg/internal/test"
 )
@@ -151,3 +155,32 @@ func repositoryFactory(providerConfig config.Provider, configVariablesClient con
 
 	return nil, errors.Errorf("invalid provider url. there are no provider implementation for %q schema", rURL.Scheme)
 }
+
+const overrideFolder = "overrides"
+
+// getLocalOverride return local override file from the config folder, if it exists.
+// This is required for development purposes, but it can be used also in production as a workaround for problems on the official repositories
+func getLocalOverride(provider config.Provider, version, path string) ([]byte, error) {
+
+	// local override files are searched at $home/cluster-api/overrides/<provider-name>/<version>/<path>
+	homeFolder := filepath.Join(homedir.HomeDir(), config.ConfigFolder)
+	overridePath := filepath.Join(homeFolder, overrideFolder, provider.Name(), version, path)
+
+	// it the local override exists, use it
+	_, err := os.Stat(overridePath)
+	if err == nil {
+		content, err := ioutil.ReadFile(overridePath)
+		if err != nil {
+			return nil, errors.Wrapf(err, "failed to read local override for %s/%s/%s", provider.Name(), version, path)
+		}
+		return content, nil
+	}
+
+	// it the local override does not exists, return (so files from the provider's repository could be used)
+	if os.IsNotExist(err) {
+		return nil, nil
+	}
+
+	// blocks for any other error
+	return nil, err
+}

cmd/clusterctl/pkg/client/repository/components_client.go

@@ -55,11 +55,17 @@ func (f *componentsClient) Get(version, targetNamespace, watchingNamespace strin
 	// retrieve the path where the path is stored
 	path := f.repository.ComponentsPath()
 
-	// read from the components path.
-	// If file is a path, the entire content of the path is returned.
-	file, err := f.repository.GetFile(version, path)
+	// read the component YAML, reading the local override file if it exists, otherwise read from the provider repository
+	file, err := getLocalOverride(f.provider, version, path)
 	if err != nil {
-		return nil, errors.Wrapf(err, "failed to read %q from the repository for provider %q", path, f.provider.Name())
+		return nil, err
+	}
+
+	if file == nil {
+		file, err = f.repository.GetFile(version, path)
+		if err != nil {
+			return nil, errors.Wrapf(err, "failed to read %q from provider's repository %q", path, f.provider.Name())
+		}
 	}
 
 	return newComponents(f.provider, version, file, f.configVariablesClient, targetNamespace, watchingNamespace)