Refactor config file location, add IPFS_CONFIG_DIR

Removed config.Filename and replace it with config.GetConfigFilePath that
takes a configuration directory as argument instead. Makes code simpler.
ipfs.getConfigDir now also return the default configuration dir instead of
an empty string in some cases.

cmd/ipfs/config.go

@@ -44,8 +44,12 @@ func init() {
 
 func configCmd(c *commander.Command, inp []string) error {
 
-	// todo: implement --config filename flag.
-	filename, err := config.Filename("")
+	confdir, err := getConfigDir(c.Parent)
+	if err != nil {
+		return err
+	}
+
+	filename, err := config.GetConfigFilePath(confdir)
 	if err != nil {
 		return err
 	}

cmd/ipfs/init.go

@@ -37,15 +37,9 @@ func initCmd(c *commander.Command, inp []string) error {
 	if err != nil {
 		return err
 	}
-	if configpath == "" {
-		configpath, err = u.TildeExpansion("~/.go-ipfs")
-		if err != nil {
-			return err
-		}
-	}
 
 	u.POut("initializing ipfs node at %s\n", configpath)
-	filename, err := config.Filename(configpath + "/config")
+	filename, err := config.GetConfigFilePath(configpath)
 	if err != nil {
 		return errors.New("Couldn't get home directory path")
 	}
@@ -69,10 +63,11 @@ func initCmd(c *commander.Command, inp []string) error {
 
 	cfg.Datastore = config.Datastore{}
 	if len(dspath) == 0 {
-		dspath, err = u.TildeExpansion("~/.go-ipfs/datastore")
+		dspath, err = config.GetDefaultPathRoot()
 		if err != nil {
 			return err
 		}
+		dspath = dspath + "/datastore"
 	}
 	cfg.Datastore.Path = dspath
 	cfg.Datastore.Type = "leveldb"
@@ -122,12 +117,7 @@ func initCmd(c *commander.Command, inp []string) error {
 		},
 	}
 
-	path, err := u.TildeExpansion(config.DefaultConfigFilePath)
-	if err != nil {
-		return err
-	}
-
-	err = config.WriteConfigFile(path, cfg)
+	err = config.WriteConfigFile(filename, cfg)
 	if err != nil {
 		return err
 	}

cmd/ipfs/ipfs.go

@@ -53,7 +53,11 @@ Use "ipfs help <command>" for more information about a command.
 }
 
 func init() {
-	CmdIpfs.Flag.String("c", config.DefaultPathRoot, "specify config directory")
+	config, err := config.GetDefaultPathRoot()
+	if err != nil {
+		config = ""
+	}
+	CmdIpfs.Flag.String("c", config, "specify config directory")
 }
 
 func ipfsCmd(c *commander.Command, args []string) error {
@@ -74,7 +78,12 @@ func main() {
 }
 
 func localNode(confdir string, online bool) (*core.IpfsNode, error) {
-	cfg, err := config.Load(confdir + "/config")
+	filename, err := config.GetConfigFilePath(confdir)
+	if err != nil {
+		return nil, err
+	}
+
+	cfg, err := config.Load(filename)
 	if err != nil {
 		return nil, err
 	}
@@ -83,16 +92,19 @@ func localNode(confdir string, online bool) (*core.IpfsNode, error) {
 }
 
 // Gets the config "-c" flag from the command, or returns
-// the empty string
+// the default configuration root directory
 func getConfigDir(c *commander.Command) (string, error) {
 	conf := c.Flag.Lookup("c").Value.Get()
 	if conf == nil {
-		return "", nil
+		return config.GetDefaultPathRoot()
 	}
 	confStr, ok := conf.(string)
 	if !ok {
 		return "", errors.New("failed to retrieve config flag value.")
 	}
+	if len(confStr) == 0 {
+		return config.GetDefaultPathRoot()
+	}
 
 	return u.TildeExpansion(confStr)
 }

config/config.go

@@ -42,11 +42,26 @@ type Config struct {
 	Bootstrap []*BootstrapPeer // local nodes's bootstrap peers
 }
 
-// DefaultPathRoot is the default parth for the IPFS node's root dir.
-const DefaultPathRoot = "~/.go-ipfs"
+// Return the default configuration root directory
+func GetDefaultPathRoot() (string, error) {
+	dir := os.Getenv("IPFS_CONFIG_DIR")
+	var err error
+	if len(dir) == 0 {
+		dir, err = u.TildeExpansion("~/.go-ipfs")
+	}
+	return dir, err
+}
 
-// DefaultConfigFilePath points to the ipfs node config file.
-const DefaultConfigFilePath = DefaultPathRoot + "/config"
+// Return the configuration file path given a configuration root directory
+// If the configuration root directory is empty, use the default one
+func GetConfigFilePath(configroot string) (string, error) {
+	if len(configroot) == 0 {
+		dir, err := GetDefaultPathRoot()
+		return dir+"/config", err
+	} else {
+		return configroot+"/config", nil
+	}
+}
 
 // DecodePrivateKey is a helper to decode the users PrivateKey
 func (i *Identity) DecodePrivateKey(passphrase string) (crypto.PrivateKey, error) {
@@ -60,30 +75,15 @@ func (i *Identity) DecodePrivateKey(passphrase string) (crypto.PrivateKey, error
 	return x509.ParsePKCS1PrivateKey(pkb)
 }
 
-// Filename returns the proper tilde expanded config filename.
-func Filename(filename string) (string, error) {
-	if len(filename) == 0 {
-		filename = DefaultConfigFilePath
-	}
-
-	// tilde expansion on config file
-	return u.TildeExpansion(filename)
-}
-
 // Load reads given file and returns the read config, or error.
 func Load(filename string) (*Config, error) {
-	filename, err := Filename(filename)
-	if err != nil {
-		return nil, err
-	}
-
 	// if nothing is there, fail. User must run 'ipfs init'
 	if _, err := os.Stat(filename); os.IsNotExist(err) {
 		return nil, errors.New("ipfs not initialized, please run 'ipfs init'")
 	}
 
 	var cfg Config
-	err = ReadConfigFile(filename, &cfg)
+	err := ReadConfigFile(filename, &cfg)
 	if err != nil {
 		return nil, err
 	}