ipfs config cmd with git-style get/set

Adds "ipfs config" command designed in git style.
See specific config's values with:

        $ipfs config datastore.path
        ~/.go-ipfs/datastore

Assign a new value with:

        $ipfs config datastore.path ~/.go-ipfs/datastore

Open the config file in your default $EDITOR:

        ipfs config edit

cmd/ipfs/config.go

+package main
+
+import (
+	"github.com/jbenet/commander"
+	config "github.com/jbenet/go-ipfs/config"
+	u "github.com/jbenet/go-ipfs/util"
+	"os"
+	"os/exec"
+)
+
+var cmdIpfsConfig = &commander.Command{
+	UsageLine: "config",
+	Short:     "See and Edit ipfs options",
+	Long: `ipfs config - See or Edit ipfs configuration.
+
+    See specific config's values with:
+	ipfs config datastore.path
+    Assign a new value with:
+	ipfs config datastore.path ~/.go-ipfs/datastore
+
+    Open the config file in your editor(from $EDITOR):
+	ipfs config edit
+  `,
+	Run: configCmd,
+	Subcommands: []*commander.Command{
+		cmdIpfsConfigEdit,
+	},
+}
+
+var cmdIpfsConfigEdit = &commander.Command{
+	UsageLine: "edit",
+	Short:     "Opens the configuration file in the editor.",
+	Long: `Looks up environment variable $EDITOR and
+	attempts to open the config file with it.
+  `,
+	Run: configEditCmd,
+}
+
+func configCmd(c *commander.Command, inp []string) error {
+	if len(inp) == 0 {
+		// "ipfs config" run without parameters
+		u.POut(c.Long + "\n")
+		return nil
+	}
+
+	if len(inp) == 1 {
+		// "ipfs config" run without one parameter, so this is a value getter
+		value, err := config.GetValueInConfigFile(inp[0])
+		if err != nil {
+			u.POut("Failed to get config value: " + err.Error() + "\n")
+		} else {
+			u.POut(value + "\n")
+		}
+		return nil
+	}
+
+	// "ipfs config" run without two parameter, so this is a value setter
+	err := config.SetValueInConfigFile(inp[0], inp[1:])
+	if err != nil {
+		u.POut("Failed to set config value: " + err.Error() + "\n")
+	}
+	return nil
+}
+
+func configEditCmd(c *commander.Command, _ []string) error {
+	if editor := os.Getenv("EDITOR"); editor == "" {
+		u.POut("ENVIRON variable $EDITOR is not assigned \n")
+	} else {
+		exec.Command("sh", "-c", editor+" "+config.DefaultConfigFilePath).Start()
+	}
+	return nil
+}

cmd/ipfs/ipfs.go

@@ -41,6 +41,7 @@ Use "ipfs help <command>" for more information about a command.
 		cmdIpfsCat,
 		cmdIpfsLs,
 		cmdIpfsRefs,
+		cmdIpfsConfig,
 		cmdIpfsVersion,
 		cmdIpfsCommands,
 		cmdIpfsMount,

config/config.go

 package config
 
 import (
-	"os"
 	u "github.com/jbenet/go-ipfs/util"
+	"os"
 )
 
 // Identity tracks the configuration of the local node's identity.
@@ -22,7 +22,7 @@ type Config struct {
 	Datastore *Datastore
 }
 
-var defaultConfigFilePath = "~/.go-ipfs/config"
+var DefaultConfigFilePath = "~/.go-ipfs/config"
 var defaultConfigFile = `{
   "identity": {},
   "datastore": {
@@ -35,7 +35,7 @@ var defaultConfigFile = `{
 // LoadConfig reads given file and returns the read config, or error.
 func LoadConfig(filename string) (*Config, error) {
 	if len(filename) == 0 {
-		filename = defaultConfigFilePath
+		filename = DefaultConfigFilePath
 	}
 
 	// tilde expansion on config file

config/serialize.go

@@ -2,9 +2,13 @@ package config
 
 import (
 	"encoding/json"
+	"errors"
+	"fmt"
+	u "github.com/jbenet/go-ipfs/util"
 	"io/ioutil"
 	"os"
 	"path"
+	"strings"
 )
 
 // WriteFile writes the given buffer `buf` into file named `filename`.
@@ -36,3 +40,82 @@ func WriteConfigFile(filename string, cfg *Config) error {
 
 	return WriteFile(filename, buf)
 }
+
+// WriteConfigFile writes the config from `cfg` into `filename`.
+func GetValueInConfigFile(key string) (value string, err error) {
+	// reading config file
+	attrs := strings.Split(key, ".")
+
+	filename, _ := u.TildeExpansion(DefaultConfigFilePath)
+	buf, err := ioutil.ReadFile(filename)
+	if err != nil {
+		return "", err
+	}
+
+	// deserializing json
+	var cfg interface{}
+	var exists bool
+
+	err = json.Unmarshal(buf, &cfg)
+	if err != nil {
+		return "", err
+	}
+
+	for i := range attrs {
+		cfgMap, isMap := cfg.(map[string]interface{})
+		if !isMap {
+			return "", errors.New(fmt.Sprintf("%s has no attributes", strings.Join(attrs[:i], ".")))
+		}
+		cfg, exists = cfgMap[attrs[i]]
+		if !exists {
+			return "", errors.New(fmt.Sprintf("Configuration option key \"%s\" not recognized", strings.Join(attrs[:i+1], ".")))
+		}
+		val, is_string := cfg.(string)
+		if is_string {
+			return val, nil
+		}
+	}
+	return "", errors.New(fmt.Sprintf("%s is not a string", key))
+}
+
+// WriteConfigFile writes the config from `cfg` into `filename`.
+func SetValueInConfigFile(key string, values []string) error {
+	assignee := strings.Join(values, " ")
+	attrs := strings.Split(key, ".")
+
+	filename, _ := u.TildeExpansion(DefaultConfigFilePath)
+	buf, err := ioutil.ReadFile(filename)
+	if err != nil {
+		return err
+	}
+
+	// deserializing json
+	var cfg, orig interface{}
+	var exists, isMap bool
+	cfgMap := make(map[string]interface{})
+
+	err = json.Unmarshal(buf, &orig)
+	cfg = orig
+	if err != nil {
+		return err
+	}
+
+	for i := 0; i < len(attrs); i++ {
+		cfgMap, isMap = cfg.(map[string]interface{})
+		// curs = append(curs, cfgMap)
+		if !isMap {
+			return errors.New(fmt.Sprintf("%s has no attributes", strings.Join(attrs[:i], ".")))
+		}
+		cfg, exists = cfgMap[attrs[i]]
+		if !exists {
+			return errors.New(fmt.Sprintf("Configuration option key \"%s\" not recognized", strings.Join(attrs[:i+1], ".")))
+		}
+	}
+	cfgMap[attrs[len(attrs)-1]] = assignee
+	buf, err = json.MarshalIndent(orig, "", "  ")
+	if err != nil {
+		return err
+	}
+	WriteFile(filename, buf)
+	return nil
+}