feat(storage): STORAGE_FILEPATH option (#2416)

- `STORAGE_FILEPATH=` disables storing to and reading from a local servers.json file
- `STORAGE_FILEPATH` defaults to `/gluetun/servers.json`
- Fix #2074

internal/configuration/settings/provider.go

@@ -25,7 +25,7 @@ type Provider struct {
 }
 
 // TODO v4 remove pointer for receiver (because of Surfshark).
-func (p *Provider) validate(vpnType string, storage Storage, warner Warner) (err error) {
+func (p *Provider) validate(vpnType string, filterChoicesGetter FilterChoicesGetter, warner Warner) (err error) {
 	// Validate Name
 	var validNames []string
 	if vpnType == vpn.OpenVPN {
@@ -48,7 +48,7 @@ func (p *Provider) validate(vpnType string, storage Storage, warner Warner) (err
 		return fmt.Errorf("%w for Wireguard: %w", ErrVPNProviderNameNotValid, err)
 	}
 
-	err = p.ServerSelection.validate(p.Name, storage, warner)
+	err = p.ServerSelection.validate(p.Name, filterChoicesGetter, warner)
 	if err != nil {
 		return fmt.Errorf("server selection: %w", err)
 	}

internal/configuration/settings/serverselection.go

@@ -91,14 +91,14 @@ var (
 )
 
 func (ss *ServerSelection) validate(vpnServiceProvider string,
-	storage Storage, warner Warner) (err error) {
+	filterChoicesGetter FilterChoicesGetter, warner Warner) (err error) {
 	switch ss.VPN {
 	case vpn.OpenVPN, vpn.Wireguard:
 	default:
 		return fmt.Errorf("%w: %s", ErrVPNTypeNotValid, ss.VPN)
 	}
 
-	filterChoices, err := getLocationFilterChoices(vpnServiceProvider, ss, storage, warner)
+	filterChoices, err := getLocationFilterChoices(vpnServiceProvider, ss, filterChoicesGetter, warner)
 	if err != nil {
 		return err // already wrapped error
 	}
@@ -142,9 +142,9 @@ func (ss *ServerSelection) validate(vpnServiceProvider string,
 }
 
 func getLocationFilterChoices(vpnServiceProvider string,
-	ss *ServerSelection, storage Storage, warner Warner) (
+	ss *ServerSelection, filterChoicesGetter FilterChoicesGetter, warner Warner) (
 	filterChoices models.FilterChoices, err error) {
-	filterChoices = storage.GetFilterChoices(vpnServiceProvider)
+	filterChoices = filterChoicesGetter.GetFilterChoices(vpnServiceProvider)
 
 	if vpnServiceProvider == providers.Surfshark {
 		// // Retro compatibility

internal/configuration/settings/settings.go

@@ -22,6 +22,7 @@ type Settings struct {
 	Log           Log
 	PublicIP      PublicIP
 	Shadowsocks   Shadowsocks
+	Storage       Storage
 	System        System
 	Updater       Updater
 	Version       Version
@@ -29,14 +30,14 @@ type Settings struct {
 	Pprof         pprof.Settings
 }
 
-type Storage interface {
+type FilterChoicesGetter interface {
 	GetFilterChoices(provider string) models.FilterChoices
 }
 
 // Validate validates all the settings and returns an error
 // if one of them is not valid.
 // TODO v4 remove pointer for receiver (because of Surfshark).
-func (s *Settings) Validate(storage Storage, ipv6Supported bool,
+func (s *Settings) Validate(filterChoicesGetter FilterChoicesGetter, ipv6Supported bool,
 	warner Warner) (err error) {
 	nameToValidation := map[string]func() error{
 		"control server":  s.ControlServer.validate,
@@ -47,12 +48,13 @@ func (s *Settings) Validate(storage Storage, ipv6Supported bool,
 		"log":             s.Log.validate,
 		"public ip check": s.PublicIP.validate,
 		"shadowsocks":     s.Shadowsocks.validate,
+		"storage":         s.Storage.validate,
 		"system":          s.System.validate,
 		"updater":         s.Updater.Validate,
 		"version":         s.Version.validate,
 		// Pprof validation done in pprof constructor
 		"VPN": func() error {
-			return s.VPN.Validate(storage, ipv6Supported, warner)
+			return s.VPN.Validate(filterChoicesGetter, ipv6Supported, warner)
 		},
 	}
 
@@ -76,6 +78,7 @@ func (s *Settings) copy() (copied Settings) {
 		Log:           s.Log.copy(),
 		PublicIP:      s.PublicIP.copy(),
 		Shadowsocks:   s.Shadowsocks.copy(),
+		Storage:       s.Storage.copy(),
 		System:        s.System.copy(),
 		Updater:       s.Updater.copy(),
 		Version:       s.Version.copy(),
@@ -85,7 +88,7 @@ func (s *Settings) copy() (copied Settings) {
 }
 
 func (s *Settings) OverrideWith(other Settings,
-	storage Storage, ipv6Supported bool, warner Warner) (err error) {
+	filterChoicesGetter FilterChoicesGetter, ipv6Supported bool, warner Warner) (err error) {
 	patchedSettings := s.copy()
 	patchedSettings.ControlServer.overrideWith(other.ControlServer)
 	patchedSettings.DNS.overrideWith(other.DNS)
@@ -95,12 +98,13 @@ func (s *Settings) OverrideWith(other Settings,
 	patchedSettings.Log.overrideWith(other.Log)
 	patchedSettings.PublicIP.overrideWith(other.PublicIP)
 	patchedSettings.Shadowsocks.overrideWith(other.Shadowsocks)
+	patchedSettings.Storage.overrideWith(other.Storage)
 	patchedSettings.System.overrideWith(other.System)
 	patchedSettings.Updater.overrideWith(other.Updater)
 	patchedSettings.Version.overrideWith(other.Version)
 	patchedSettings.VPN.OverrideWith(other.VPN)
 	patchedSettings.Pprof.OverrideWith(other.Pprof)
-	err = patchedSettings.Validate(storage, ipv6Supported, warner)
+	err = patchedSettings.Validate(filterChoicesGetter, ipv6Supported, warner)
 	if err != nil {
 		return err
 	}
@@ -117,6 +121,7 @@ func (s *Settings) SetDefaults() {
 	s.Log.setDefaults()
 	s.PublicIP.setDefaults()
 	s.Shadowsocks.setDefaults()
+	s.Storage.setDefaults()
 	s.System.setDefaults()
 	s.Version.setDefaults()
 	s.VPN.setDefaults()
@@ -139,6 +144,7 @@ func (s Settings) toLinesNode() (node *gotree.Node) {
 	node.AppendNode(s.Shadowsocks.toLinesNode())
 	node.AppendNode(s.HTTPProxy.toLinesNode())
 	node.AppendNode(s.ControlServer.toLinesNode())
+	node.AppendNode(s.Storage.toLinesNode())
 	node.AppendNode(s.System.toLinesNode())
 	node.AppendNode(s.PublicIP.toLinesNode())
 	node.AppendNode(s.Updater.toLinesNode())
@@ -188,6 +194,7 @@ func (s *Settings) Read(r *reader.Reader) (err error) {
 		"log":            s.Log.read,
 		"public ip":      s.PublicIP.read,
 		"shadowsocks":    s.Shadowsocks.read,
+		"storage":        s.Storage.read,
 		"system":         s.System.read,
 		"updater":        s.Updater.read,
 		"version":        s.Version.read,

internal/configuration/settings/storage.go

@@ -0,0 +1,59 @@
+package settings
+
+import (
+	"fmt"
+	"path/filepath"
+
+	"github.com/qdm12/gosettings"
+	"github.com/qdm12/gosettings/reader"
+	"github.com/qdm12/gotree"
+)
+
+// Storage contains settings to configure the storage.
+type Storage struct {
+	// Filepath is the path to the servers.json file. An empty string disables on-disk storage.
+	Filepath *string
+}
+
+func (s Storage) validate() (err error) {
+	if *s.Filepath != "" { // optional
+		_, err := filepath.Abs(*s.Filepath)
+		if err != nil {
+			return fmt.Errorf("filepath is not valid: %w", err)
+		}
+	}
+	return nil
+}
+
+func (s *Storage) copy() (copied Storage) {
+	return Storage{
+		Filepath: gosettings.CopyPointer(s.Filepath),
+	}
+}
+
+func (s *Storage) overrideWith(other Storage) {
+	s.Filepath = gosettings.OverrideWithPointer(s.Filepath, other.Filepath)
+}
+
+func (s *Storage) setDefaults() {
+	const defaultFilepath = "/gluetun/servers.json"
+	s.Filepath = gosettings.DefaultPointer(s.Filepath, defaultFilepath)
+}
+
+func (s Storage) String() string {
+	return s.toLinesNode().String()
+}
+
+func (s Storage) toLinesNode() (node *gotree.Node) {
+	if *s.Filepath == "" {
+		return gotree.New("Storage settings: disabled")
+	}
+	node = gotree.New("Storage settings:")
+	node.Appendf("Filepath: %s", *s.Filepath)
+	return node
+}
+
+func (s *Storage) read(r *reader.Reader) (err error) {
+	s.Filepath = r.Get("STORAGE_FILEPATH", reader.AcceptEmpty(true))
+	return nil
+}

internal/configuration/settings/vpn.go

@@ -21,14 +21,14 @@ type VPN struct {
 }
 
 // TODO v4 remove pointer for receiver (because of Surfshark).
-func (v *VPN) Validate(storage Storage, ipv6Supported bool, warner Warner) (err error) {
+func (v *VPN) Validate(filterChoicesGetter FilterChoicesGetter, ipv6Supported bool, warner Warner) (err error) {
 	// Validate Type
 	validVPNTypes := []string{vpn.OpenVPN, vpn.Wireguard}
 	if err = validate.IsOneOf(v.Type, validVPNTypes...); err != nil {
 		return fmt.Errorf("%w: %w", ErrVPNTypeNotValid, err)
 	}
 
-	err = v.Provider.validate(v.Type, storage, warner)
+	err = v.Provider.validate(v.Type, filterChoicesGetter, warner)
 	if err != nil {
 		return fmt.Errorf("provider settings: %w", err)
 	}