add portable mode

Portable mode is a convenient way to share a single directory on demand

service/service.go

@@ -2,12 +2,20 @@
 package service
 
 import (
+	"fmt"
+	"math/rand"
+	"os"
+	"path/filepath"
+	"strings"
+	"time"
+
 	"github.com/drakkan/sftpgo/config"
 	"github.com/drakkan/sftpgo/dataprovider"
 	"github.com/drakkan/sftpgo/httpd"
 	"github.com/drakkan/sftpgo/logger"
 	"github.com/drakkan/sftpgo/sftpd"
 	"github.com/drakkan/sftpgo/utils"
+	"github.com/rs/xid"
 	"github.com/rs/zerolog"
 )
 
@@ -15,6 +23,10 @@ const (
 	logSender = "service"
 )
 
+var (
+	chars = []rune("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789")
+)
+
 // Service defines the SFTPGo service
 type Service struct {
 	ConfigDir     string
@@ -25,6 +37,8 @@ type Service struct {
 	LogMaxAge     int
 	LogCompress   bool
 	LogVerbose    bool
+	PortableMode  int
+	PortableUser  dataprovider.User
 	Shutdown      chan bool
 }
 
@@ -39,7 +53,10 @@ func (s *Service) Start() error {
 	logger.Info(logSender, "", "starting SFTPGo %v, config dir: %v, config file: %v, log max size: %v log max backups: %v "+
 		"log max age: %v log verbose: %v, log compress: %v", version.GetVersionAsString(), s.ConfigDir, s.ConfigFile, s.LogMaxSize,
 		s.LogMaxBackups, s.LogMaxAge, s.LogVerbose, s.LogCompress)
-	config.LoadConfig(s.ConfigDir, s.ConfigFile)
+	// in portable mode we don't read configuration from file
+	if s.PortableMode != 1 {
+		config.LoadConfig(s.ConfigDir, s.ConfigFile)
+	}
 	providerConf := config.GetProviderConf()
 
 	err := dataprovider.Initialize(providerConf, s.ConfigDir)
@@ -53,6 +70,15 @@ func (s *Service) Start() error {
 	sftpdConf := config.GetSFTPDConfig()
 	httpdConf := config.GetHTTPDConfig()
 
+	if s.PortableMode == 1 {
+		// create the user for portable mode
+		err = dataprovider.AddUser(dataProvider, s.PortableUser)
+		if err != nil {
+			logger.ErrorToConsole("error adding portable user: %v", err)
+			return err
+		}
+	}
+
 	sftpd.SetDataProvider(dataProvider)
 
 	go func() {
@@ -76,7 +102,14 @@ func (s *Service) Start() error {
 		}()
 	} else {
 		logger.Debug(logSender, "", "HTTP server not started, disabled in config file")
-		logger.DebugToConsole("HTTP server not started, disabled in config file")
+		if s.PortableMode != 1 {
+			logger.DebugToConsole("HTTP server not started, disabled in config file")
+		}
+	}
+	if s.PortableMode == 1 {
+		logger.InfoToConsole("Portable mode ready, SFTP port: %v, user: %#v, password: %#v, public keys: %v, directory: %#v, permissions: %v,"+
+			" SCP enabled: %v", sftpdConf.BindPort, s.PortableUser.Username, s.PortableUser.Password, s.PortableUser.PublicKeys,
+			s.PortableUser.HomeDir, s.PortableUser.Permissions, sftpdConf.IsSCPEnabled)
 	}
 	return nil
 }
@@ -91,3 +124,44 @@ func (s *Service) Stop() {
 	close(s.Shutdown)
 	logger.Debug(logSender, "", "Service stopped")
 }
+
+// StartPortableMode starts the service in portable mode
+func (s *Service) StartPortableMode(sftpdPort int, enableSCP bool) error {
+	rand.Seed(time.Now().UnixNano())
+	if s.PortableMode != 1 {
+		return fmt.Errorf("service is not configured for portable mode")
+	}
+	if len(s.PortableUser.Username) == 0 {
+		s.PortableUser.Username = "user"
+	}
+	if len(s.PortableUser.PublicKeys) == 0 && len(s.PortableUser.Password) == 0 {
+		var b strings.Builder
+		for i := 0; i < 8; i++ {
+			b.WriteRune(chars[rand.Intn(len(chars))])
+		}
+		s.PortableUser.Password = b.String()
+	}
+	tempDir := os.TempDir()
+	instanceID := xid.New().String()
+	databasePath := filepath.Join(tempDir, instanceID+".db")
+	s.LogFilePath = filepath.Join(tempDir, instanceID+".log")
+	dataProviderConf := config.GetProviderConf()
+	dataProviderConf.Driver = dataprovider.BoltDataProviderName
+	dataProviderConf.Name = databasePath
+	config.SetProviderConf(dataProviderConf)
+	httpdConf := config.GetHTTPDConfig()
+	httpdConf.BindPort = 0
+	config.SetHTTPDConfig(httpdConf)
+	sftpdConf := config.GetSFTPDConfig()
+	sftpdConf.MaxAuthTries = 12
+	if sftpdPort > 0 {
+		sftpdConf.BindPort = sftpdPort
+	} else {
+		// dynamic ports starts from 49152
+		sftpdConf.BindPort = 49152 + rand.Intn(15000)
+	}
+	sftpdConf.IsSCPEnabled = enableSCP
+	config.SetSFTPDConfig(sftpdConf)
+
+	return s.Start()
+}