Use pointers in struct methods to avoid object copies

Author: arunvelsriram

cmd/generate.go

@@ -24,7 +24,7 @@ var generateCmd = &cobra.Command{
 		}
 		bufioReader := bufio.NewReader(reader)
 
-		kubeCfg, err := kubeconfig.New(filesystem.Default{}, commander.Default{})
+		kubeCfg, err := kubeconfig.New(&filesystem.Default{}, &commander.Default{})
 		if err != nil {
 			fmt.Println(err)
 			os.Exit(1)

pkg/commander/commander.go

@@ -15,7 +15,7 @@ type Commander interface {
 type Default struct{}
 
 // Execute executes a command on the actual machine
-func (Default) Execute(cmdStr string, args []string, envs []string) (string, error) {
+func (d *Default) Execute(cmdStr string, args []string, envs []string) (string, error) {
 	cmd := exec.Command(cmdStr, args...)
 	cmd.Env = os.Environ()
 	cmd.Env = append(cmd.Env, envs...)

pkg/filesystem/filesystem.go

@@ -16,7 +16,7 @@ type FileSystem interface {
 type Default struct{}
 
 // Remove removes a file from Default filesystem
-func (Default) Remove(file string) error {
+func (d *Default) Remove(file string) error {
 	if err := os.Remove(file); err != nil {
 		return err
 	}
@@ -25,7 +25,7 @@ func (Default) Remove(file string) error {
 }
 
 // HomeDir returns the home directory
-func (Default) HomeDir() (string, error) {
+func (d *Default) HomeDir() (string, error) {
 	home, err := homedir.Dir()
 	if err != nil {
 		return home, err

pkg/kubeconfig/kubeconfig.go

@@ -17,7 +17,7 @@ type KubeConfig struct {
 }
 
 // Delete deletes the kubeconfig file for the given context
-func (k KubeConfig) Delete(kubeCfgFile string) error {
+func (k *KubeConfig) Delete(kubeCfgFile string) error {
 	if err := k.filesystem.Remove(kubeCfgFile); err != nil && !os.IsNotExist(err) {
 		return err
 	}
@@ -27,7 +27,7 @@ func (k KubeConfig) Delete(kubeCfgFile string) error {
 
 // AddRegionalCluster imports Kubernetes context for
 // regional Kubernetes cluster
-func (k KubeConfig) AddRegionalCluster(project string, cluster string, region string, kubeCfgFile string) error {
+func (k *KubeConfig) AddRegionalCluster(project string, cluster string, region string, kubeCfgFile string) error {
 	args := []string{
 		"beta",
 		"container",
@@ -51,7 +51,7 @@ func (k KubeConfig) AddRegionalCluster(project string, cluster string, region st
 
 // AddZonalCluster imports Kubernetes context for
 // zonal Kubernetes cluster
-func (k KubeConfig) AddZonalCluster(project string, cluster string, zone string, kubeCfgFile string) error {
+func (k *KubeConfig) AddZonalCluster(project string, cluster string, zone string, kubeCfgFile string) error {
 	args := []string{
 		"container",
 		"clusters",
@@ -71,7 +71,7 @@ func (k KubeConfig) AddZonalCluster(project string, cluster string, zone string,
 }
 
 // RenameContext renames a Kubernetes context
-func (k KubeConfig) RenameContext(oldCtx string, newCtx string, kubeCfgFile string) error {
+func (k *KubeConfig) RenameContext(oldCtx string, newCtx string, kubeCfgFile string) error {
 	args := []string{
 		"config",
 		"rename-context",
@@ -89,7 +89,7 @@ func (k KubeConfig) RenameContext(oldCtx string, newCtx string, kubeCfgFile stri
 }
 
 // KubeCfgsDir returns the directory in which kube configs are stored
-func (k KubeConfig) KubeCfgsDir() string {
+func (k *KubeConfig) KubeCfgsDir() string {
 	return k.kubeCfgsDir
 }
 

pkg/kubetmuxp/kubetmuxp.go

@@ -23,7 +23,7 @@ type Cluster struct {
 }
 
 // DefaultContextName returns default context name
-func (c Cluster) DefaultContextName(project string) (string, error) {
+func (c *Cluster) DefaultContextName(project string) (string, error) {
 	if regional, err := c.IsRegional(); err != nil {
 		return "", err
 	} else if regional {
@@ -34,7 +34,7 @@ func (c Cluster) DefaultContextName(project string) (string, error) {
 }
 
 // IsRegional tells if a cluster is a regional cluster
-func (c Cluster) IsRegional() (bool, error) {
+func (c *Cluster) IsRegional() (bool, error) {
 	if c.Region != "" && c.Zone != "" {
 		return false, fmt.Errorf("Only one of region or zone should be given")
 	}
@@ -81,7 +81,7 @@ func (c *Config) Load() error {
 }
 
 // Process processes kube-tmuxp configs
-func (c Config) Process() error {
+func (c *Config) Process() error {
 	kubeCfgsDir := c.kubeCfg.KubeCfgsDir()
 	for _, project := range c.Projects {
 		for _, cluster := range project.Clusters {