🐛 Fix Defaulting of the User Agent

This broke when we added the HTTP client, because the user-agent gets
set by a roundtripper that is constructed within `rest.HTTPClientFor`.
As a result, we have to default it before we do that. Currently, it ends
up being defaulted to `Go-http-client` which is not very useful.

pkg/cache/cache.go

@@ -334,6 +334,11 @@ func newCache(restConfig *rest.Config, opts Options) newCacheFunc {
 }
 
 func defaultOpts(config *rest.Config, opts Options) (Options, error) {
+	config = rest.CopyConfig(config)
+	if config.UserAgent == "" {
+		config.UserAgent = rest.DefaultKubernetesUserAgent()
+	}
+
 	// Use the rest HTTP client for the provided config if unset
 	if opts.HTTPClient == nil {
 		var err error

pkg/client/client.go

@@ -110,14 +110,18 @@ func newClient(config *rest.Config, options Options) (*client, error) {
 		return nil, fmt.Errorf("must provide non-nil rest.Config to client.New")
 	}
 
+	config = rest.CopyConfig(config)
+	if config.UserAgent == "" {
+		config.UserAgent = rest.DefaultKubernetesUserAgent()
+	}
+
 	if !options.WarningHandler.SuppressWarnings {
 		// surface warnings
 		logger := log.Log.WithName("KubeAPIWarningLogger")
 		// Set a WarningHandler, the default WarningHandler
 		// is log.KubeAPIWarningLogger with deduplication enabled.
 		// See log.KubeAPIWarningLoggerOptions for considerations
 		// regarding deduplication.
-		config = rest.CopyConfig(config)
 		config.WarningHandler = log.NewKubeAPIWarningLogger(
 			logger,
 			log.KubeAPIWarningLoggerOptions{
@@ -160,7 +164,7 @@ func newClient(config *rest.Config, options Options) (*client, error) {
 		unstructuredResourceByType: make(map[schema.GroupVersionKind]*resourceMeta),
 	}
 
-	rawMetaClient, err := metadata.NewForConfigAndClient(config, options.HTTPClient)
+	rawMetaClient, err := metadata.NewForConfigAndClient(metadata.ConfigFor(config), options.HTTPClient)
 	if err != nil {
 		return nil, fmt.Errorf("unable to construct metadata-only client for use as part of client: %w", err)
 	}

pkg/cluster/cluster.go

@@ -158,6 +158,11 @@ func New(config *rest.Config, opts ...Option) (Cluster, error) {
 		return nil, errors.New("must specify Config")
 	}
 
+	config = rest.CopyConfig(config)
+	if config.UserAgent == "" {
+		config.UserAgent = rest.DefaultKubernetesUserAgent()
+	}
+
 	options := Options{}
 	for _, opt := range opts {
 		opt(&options)

pkg/manager/manager.go

@@ -322,6 +322,11 @@ func New(config *rest.Config, options Options) (Manager, error) {
 	// Set default values for options fields
 	options = setOptionsDefaults(options)
 
+	config = rest.CopyConfig(config)
+	if config.UserAgent == "" {
+		config.UserAgent = rest.DefaultKubernetesUserAgent()
+	}
+
 	cluster, err := cluster.New(config, func(clusterOptions *cluster.Options) {
 		clusterOptions.Scheme = options.Scheme
 		clusterOptions.MapperProvider = options.MapperProvider