Config store helper

cmd/common.go

@@ -262,13 +262,25 @@ func verifyCert(caCert []byte) (string, error) {
 }
 
 func loadConfig(ctx *cli.Context) (config.Config, error) {
+	switch ctx.GlobalString("config-helper") {
+	case "built-in":
+		return loadConfigNative(ctx)
+	default:
+		// allow loading of rancher config by triggering an
+		// external helper executable
+		return loadConfigWithHelper(ctx)
+	}
+}
+
+func loadConfigNative(ctx *cli.Context) (config.Config, error) {
 	// path will always be set by the global flag default
 	path := ctx.GlobalString("config")
 	path = filepath.Join(path, cfgFile)
 
 	cf := config.Config{
 		Path:    path,
 		Servers: make(map[string]*config.ServerConfig),
+		Helper:  ctx.GlobalString("config-helper"),
 	}
 
 	content, err := ioutil.ReadFile(path)
@@ -284,6 +296,26 @@ func loadConfig(ctx *cli.Context) (config.Config, error) {
 	return cf, err
 }
 
+// fetch rancher cli config by executing an external helper
+func loadConfigWithHelper(ctx *cli.Context) (config.Config, error) {
+	cf := config.Config{
+		Path:    "",
+		Servers: make(map[string]*config.ServerConfig),
+		Helper:  ctx.GlobalString("config-helper"),
+	}
+
+	cmd := exec.Command(ctx.GlobalString("config-helper"), "get")
+	cmd.Stderr = os.Stderr
+	cmd.Stdin = os.Stdin
+	content, err := cmd.Output()
+	if err != nil {
+		return cf, err
+	}
+
+	err = json.Unmarshal(content, &cf)
+	return cf, err
+}
+
 func lookupConfig(ctx *cli.Context) (*config.ServerConfig, error) {
 	cf, err := loadConfig(ctx)
 	if err != nil {

config/config.go

@@ -4,6 +4,7 @@ import (
 	"encoding/json"
 	"net/url"
 	"os"
+	"os/exec"
 	"path"
 	"strings"
 
@@ -18,6 +19,8 @@ type Config struct {
 	Path string `json:"path,omitempty"`
 	// CurrentServer the user has in focus
 	CurrentServer string
+	// Helper executable to store config
+	Helper string
 }
 
 //ServerConfig holds the config for each server the user has setup
@@ -33,6 +36,17 @@ type ServerConfig struct {
 }
 
 func (c Config) Write() error {
+	switch c.Helper {
+	case "built-in":
+		return c.writeNative()
+	default:
+		// if rancher config was loaded by external helper
+		// use the same helper to persist the config
+		return c.writeWithHelper()
+	}
+}
+
+func (c Config) writeNative() error {
 	err := os.MkdirAll(path.Dir(c.Path), 0700)
 	if err != nil {
 		return err
@@ -50,6 +64,19 @@ func (c Config) Write() error {
 	return json.NewEncoder(output).Encode(c)
 }
 
+func (c Config) writeWithHelper() error {
+	logrus.Infof("Saving config with helper %s", c.Helper)
+	jsonConfig, err := json.Marshal(c)
+	if err != nil {
+		return err
+	}
+	cmd := exec.Command(c.Helper, "store", string(jsonConfig))
+	cmd.Stderr = os.Stderr
+	cmd.Stdin = os.Stdin
+	err = cmd.Run()
+	return err
+}
+
 func (c Config) FocusedServer() *ServerConfig {
 	return c.Servers[c.CurrentServer]
 }

main.go

@@ -86,6 +86,12 @@ func mainErr() error {
 			EnvVar: "RANCHER_CONFIG_DIR",
 			Value:  os.ExpandEnv("${HOME}/.rancher"),
 		},
+		cli.StringFlag{
+			Name:   "config-helper",
+			Usage:  "Helper executable to load/store config",
+			EnvVar: "RANCHER_CONFIG_HELPER",
+			Value:  os.ExpandEnv("built-in"),
+		},
 	}
 	app.Commands = []cli.Command{
 		cmd.AppCommand(),