add config set command (#130)

update the params of ~/.micromdm/default.json using the CLI

cmd/mdmctl/config.go

@@ -2,24 +2,125 @@ package main
 
 import (
 	"encoding/json"
+	"flag"
 	"fmt"
 	"io/ioutil"
+	"net/url"
+	"os"
 	"os/user"
+	"strings"
 )
 
-func NewClientConfig() (*ClientConfig, error) {
+type configCommand struct {
+	config *ClientConfig
+}
+
+func (cmd *configCommand) Run(args []string) error {
+	if len(args) < 1 {
+		cmd.Usage()
+		os.Exit(1)
+	}
+
+	var config *ClientConfig
+	if cfg, err := LoadClientConfig(); err == nil {
+		config = cfg
+	} else {
+		config = new(ClientConfig)
+	}
+	var run func(*ClientConfig, []string) error
+	switch strings.ToLower(args[0]) {
+	case "set":
+		run = setCmd
+	default:
+		cmd.Usage()
+		os.Exit(1)
+	}
+
+	return run(config, args[1:])
+}
+
+func (cmd *configCommand) Usage() error {
+	const help = `
+mdmctl config set -h
+`
+	fmt.Println(help)
+	return nil
+}
+
+func setCmd(cfg *ClientConfig, args []string) error {
+	flagset := flag.NewFlagSet("set", flag.ExitOnError)
+	var (
+		flToken     = flagset.String("api-token", "", "api token to connect to micromdm server")
+		flServerURL = flagset.String("server-url", "", "server url of micromdm server")
+	)
+
+	flagset.Usage = usageFor(flagset, "mdmctl config set [flags]")
+	if err := flagset.Parse(args); err != nil {
+		return err
+	}
+
+	if *flToken != "" {
+		cfg.APIToken = *flToken
+	}
+
+	if *flServerURL != "" {
+		if !strings.HasPrefix(*flServerURL, "http") ||
+			!strings.HasPrefix(*flServerURL, "https") {
+			*flServerURL = "https://" + *flServerURL
+		}
+		u, err := url.Parse(*flServerURL)
+		if err != nil {
+			return err
+		}
+		u.Scheme = "https"
+		u.Path = "/"
+		cfg.ServerURL = u.String()
+	}
+
+	return SaveClientConfig(cfg)
+}
+
+func clientConfigPath() (string, error) {
 	usr, err := user.Current()
+	if err != nil {
+		return "", err
+	}
+	path := usr.HomeDir + "/.micromdm/default.json"
+	return path, nil
+}
+
+func SaveClientConfig(cfg *ClientConfig) error {
+	path, err := clientConfigPath()
+	if err != nil {
+		return err
+	}
+	f, err := os.OpenFile(path, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0644)
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+
+	if cfg == nil {
+		cfg = new(ClientConfig)
+	}
+	enc := json.NewEncoder(f)
+	enc.SetIndent("", "  ")
+	return enc.Encode(cfg)
+}
+
+func LoadClientConfig() (*ClientConfig, error) {
+	path, err := clientConfigPath()
 	if err != nil {
 		return nil, err
 	}
-	cfgData, err := ioutil.ReadFile(usr.HomeDir + "/.micromdm/default.json")
+	cfgData, err := ioutil.ReadFile(path)
 	if err != nil {
 		return nil, fmt.Errorf("unable to load default config file: %s", err)
 	}
 	var cfg ClientConfig
 	err = json.Unmarshal(cfgData, &cfg)
 	if err != nil {
-		return nil, fmt.Errorf("failed to unmarshal ~/.micromdm/default.json %s", err)
+		return nil, fmt.Errorf("failed to unmarshal %s : %s", path, err)
 	}
 	return &cfg, nil
 }

cmd/mdmctl/get.go

@@ -18,7 +18,7 @@ type getCommand struct {
 }
 
 func (cmd *getCommand) setup() error {
-	cfg, err := NewClientConfig()
+	cfg, err := LoadClientConfig()
 	if err != nil {
 		return err
 	}
@@ -86,7 +86,7 @@ func (out *devicesTableOutput) BasicFooter() {
 
 func (cmd *getCommand) getDevices(args []string) error {
 	flagset := flag.NewFlagSet("devices", flag.ExitOnError)
-	flagset.Usage = usageFor(flagset, "micromdm get devices [flags]")
+	flagset.Usage = usageFor(flagset, "mdmctl get devices [flags]")
 	if err := flagset.Parse(args); err != nil {
 		return err
 	}

cmd/mdmctl/mdmdctl.go

@@ -20,6 +20,9 @@ func main() {
 	case "version", "-version":
 		version.Print()
 		return
+	case "config":
+		cmd := &configCommand{}
+		run = cmd.Run
 	case "get":
 		cmd := &getCommand{}
 		run = cmd.Run
@@ -39,6 +42,7 @@ func usage() error {
 
 Available Commands:
 	get
+	config
 	version
 
 Use micromdm <command> -h for additional usage of each command.