chore(client): introduce extensible YAML config in Go

client/go/outline/client.go

@@ -15,21 +15,20 @@
 package outline
 
 import (
-	"fmt"
-	"net"
+	"context"
 
+	"github.com/Jigsaw-Code/outline-apps/client/go/outline/config"
 	"github.com/Jigsaw-Code/outline-apps/client/go/outline/platerrors"
 	"github.com/Jigsaw-Code/outline-sdk/transport"
-	"github.com/Jigsaw-Code/outline-sdk/transport/shadowsocks"
-	"github.com/eycorsican/go-tun2socks/common/log"
 )
 
 // Client provides a transparent container for [transport.StreamDialer] and [transport.PacketListener]
 // that is exportable (as an opaque object) via gobind.
 // It's used by the connectivity test and the tun2socks handlers.
+// TODO: Rename to Transport. Needs to update per-platform code.
 type Client struct {
-	transport.StreamDialer
-	transport.PacketListener
+	*config.Dialer[transport.StreamConn]
+	*config.PacketListener
 }
 
 // NewClientResult represents the result of [NewClientAndReturnError].
@@ -42,61 +41,29 @@ type NewClientResult struct {
 
 // NewClient creates a new Outline client from a configuration string.
 func NewClient(transportConfig string) *NewClientResult {
-	config, err := parseConfigFromJSON(transportConfig)
+	transportYAML, err := config.ParseConfigYAML(transportConfig)
 	if err != nil {
-		return &NewClientResult{Error: platerrors.ToPlatformError(err)}
-	}
-	prefixBytes, err := ParseConfigPrefixFromString(config.Prefix)
-	if err != nil {
-		return &NewClientResult{Error: platerrors.ToPlatformError(err)}
-	}
-
-	client, err := newShadowsocksClient(config.Host, int(config.Port), config.Method, config.Password, prefixBytes)
-	return &NewClientResult{
-		Client: client,
-		Error:  platerrors.ToPlatformError(err),
-	}
-}
-
-func newShadowsocksClient(host string, port int, cipherName, password string, prefix []byte) (*Client, error) {
-	if err := validateConfig(host, port, cipherName, password); err != nil {
-		return nil, err
-	}
-
-	// TODO: consider using net.LookupIP to get a list of IPs, and add logic for optimal selection.
-	proxyAddress := net.JoinHostPort(host, fmt.Sprint(port))
-
-	cryptoKey, err := shadowsocks.NewEncryptionKey(cipherName, password)
-	if err != nil {
-		return nil, newIllegalConfigErrorWithDetails("cipher&password pair is not valid",
-			"cipher|password", cipherName+"|"+password, "valid combination", err)
-	}
-
-	// We disable Keep-Alive as per https://datatracker.ietf.org/doc/html/rfc1122#page-101, which states that it should only be
-	// enabled in server applications. This prevents the device from unnecessarily waking up to send keep alives.
-	streamDialer, err := shadowsocks.NewStreamDialer(&transport.TCPEndpoint{Address: proxyAddress, Dialer: net.Dialer{KeepAlive: -1}}, cryptoKey)
-	if err != nil {
-		return nil, platerrors.PlatformError{
-			Code:    platerrors.SetupTrafficHandlerFailed,
-			Message: "failed to create TCP traffic handler",
-			Details: platerrors.ErrorDetails{"proxy-protocol": "shadowsocks", "handler": "tcp"},
-			Cause:   platerrors.ToPlatformError(err),
+		return &NewClientResult{
+			Error: &platerrors.PlatformError{
+				Code:    platerrors.IllegalConfig,
+				Message: "config is not valid YAML",
+				Cause:   platerrors.ToPlatformError(err),
+			},
 		}
 	}
-	if len(prefix) > 0 {
-		log.Debugf("Using salt prefix: %s", string(prefix))
-		streamDialer.SaltGenerator = shadowsocks.NewPrefixSaltGenerator(prefix)
-	}
 
-	packetListener, err := shadowsocks.NewPacketListener(&transport.UDPEndpoint{Address: proxyAddress}, cryptoKey)
+	transportPair, err := config.NewDefaultTransportProvider().Parse(context.Background(), transportYAML)
 	if err != nil {
-		return nil, platerrors.PlatformError{
-			Code:    platerrors.SetupTrafficHandlerFailed,
-			Message: "failed to create UDP traffic handler",
-			Details: platerrors.ErrorDetails{"proxy-protocol": "shadowsocks", "handler": "udp"},
-			Cause:   platerrors.ToPlatformError(err),
+		return &NewClientResult{
+			Error: &platerrors.PlatformError{
+				Code:    platerrors.IllegalConfig,
+				Message: "failed to create transport",
+				Cause:   platerrors.ToPlatformError(err),
+			},
 		}
 	}
 
-	return &Client{StreamDialer: streamDialer, PacketListener: packetListener}, nil
+	return &NewClientResult{
+		Client: &Client{Dialer: transportPair.StreamDialer, PacketListener: transportPair.PacketListener},
+	}
 }

client/go/outline/client_test.go

@@ -14,7 +14,201 @@
 
 package outline
 
-import "testing"
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func Test_NewTransport_SS_URL(t *testing.T) {
+	config := "ss://[email protected]:4321/"
+	firstHop := "example.com:4321"
+
+	result := NewClient(config)
+	require.Nil(t, result.Error, "Got %v", result.Error)
+	require.Equal(t, firstHop, result.Client.Dialer.FirstHop)
+	require.Equal(t, firstHop, result.Client.PacketListener.FirstHop)
+}
+
+func Test_NewTransport_Legacy_JSON(t *testing.T) {
+	config := `{
+    "server": "example.com",
+    "server_port": 4321,
+    "method": "chacha20-ietf-poly1305",
+    "password": "SECRET"
+}`
+	firstHop := "example.com:4321"
+
+	result := NewClient(config)
+	require.Nil(t, result.Error, "Got %v", result.Error)
+	require.Equal(t, firstHop, result.Client.Dialer.FirstHop)
+	require.Equal(t, firstHop, result.Client.PacketListener.FirstHop)
+}
+
+func Test_NewTransport_Flexible_JSON(t *testing.T) {
+	config := `{
+    # Comment
+    server: example.com,
+    server_port: 4321,
+    method: chacha20-ietf-poly1305,
+    password: SECRET
+}`
+	firstHop := "example.com:4321"
+
+	result := NewClient(config)
+	require.Nil(t, result.Error, "Got %v", result.Error)
+	require.Equal(t, firstHop, result.Client.Dialer.FirstHop)
+	require.Equal(t, firstHop, result.Client.PacketListener.FirstHop)
+}
+
+func Test_NewTransport_YAML(t *testing.T) {
+	config := `# Comment
+server: example.com
+server_port: 4321
+method: chacha20-ietf-poly1305
+password: SECRET`
+	firstHop := "example.com:4321"
+
+	result := NewClient(config)
+	require.Nil(t, result.Error, "Got %v", result.Error)
+	require.Equal(t, firstHop, result.Client.Dialer.FirstHop)
+	require.Equal(t, firstHop, result.Client.PacketListener.FirstHop)
+}
+
+func Test_NewTransport_Explicit_endpoint(t *testing.T) {
+	config := `
+endpoint:
+    $parser: dial
+    address: example.com:4321
+cipher: chacha20-ietf-poly1305
+secret: SECRET`
+	firstHop := "example.com:4321"
+
+	result := NewClient(config)
+	require.Nil(t, result.Error, "Got %v", result.Error)
+	require.Equal(t, firstHop, result.Client.Dialer.FirstHop)
+	require.Equal(t, firstHop, result.Client.PacketListener.FirstHop)
+}
+
+func Test_NewTransport_Multihop_URL(t *testing.T) {
+	config := `
+endpoint:
+    $parser: dial
+    address: exit.example.com:4321
+    dialer: ss://[email protected]:4321/
+cipher: chacha20-ietf-poly1305
+secret: SECRET`
+	firstHop := "entry.example.com:4321"
+
+	result := NewClient(config)
+	require.Nil(t, result.Error, "Got %v", result.Error)
+	require.Equal(t, firstHop, result.Client.Dialer.FirstHop)
+	require.Equal(t, firstHop, result.Client.PacketListener.FirstHop)
+}
+
+func Test_NewTransport_Multihop_Explicit(t *testing.T) {
+	config := `
+endpoint:
+    $parser: dial
+    address: exit.example.com:4321
+    dialer: 
+      $parser: shadowsocks
+      endpoint: entry.example.com:4321
+      cipher: chacha20-ietf-poly1305
+      secret: ENTRY_SECRET
+cipher: chacha20-ietf-poly1305
+secret: EXIT_SECRET`
+	firstHop := "entry.example.com:4321"
+
+	result := NewClient(config)
+	require.Nil(t, result.Error, "Got %v", result.Error)
+	require.Equal(t, firstHop, result.Client.Dialer.FirstHop)
+	require.Equal(t, firstHop, result.Client.PacketListener.FirstHop)
+}
+
+func Test_NewTransport_Explicit_TCPUDP(t *testing.T) {
+	config := `
+$parser: tcpudp
+tcp:
+    $parser: shadowsocks
+    endpoint: example.com:80
+    cipher: chacha20-ietf-poly1305
+    secret: SECRET
+    prefix: "POST "
+udp:
+    $parser: shadowsocks
+    endpoint: example.com:53
+    cipher: chacha20-ietf-poly1305
+    secret: SECRET`
+
+	result := NewClient(config)
+	require.Nil(t, result.Error, "Got %v", result.Error)
+	require.Equal(t, "example.com:80", result.Client.Dialer.FirstHop)
+	require.Equal(t, "example.com:53", result.Client.PacketListener.FirstHop)
+}
+
+func Test_NewTransport_YAML_Reuse(t *testing.T) {
+	config := `
+$parser: tcpudp
+udp: &base
+    $parser: shadowsocks
+    endpoint: example.com:4321
+    cipher: chacha20-ietf-poly1305
+    secret: SECRET
+tcp:
+    <<: *base
+    prefix: "POST "`
+	firstHop := "example.com:4321"
+
+	result := NewClient(config)
+	require.Nil(t, result.Error, "Got %v", result.Error)
+	require.Equal(t, firstHop, result.Client.Dialer.FirstHop)
+	require.Equal(t, firstHop, result.Client.PacketListener.FirstHop)
+}
+
+func Test_NewTransport_YAML_Partial_Reuse(t *testing.T) {
+	config := `
+$parser: tcpudp
+tcp:
+    $parser: shadowsocks
+    endpoint: example.com:80
+    <<: &cipher
+      cipher: chacha20-ietf-poly1305
+      secret: SECRET
+    prefix: "POST "
+udp:
+    $parser: shadowsocks
+    endpoint: example.com:53
+    <<: *cipher`
+
+	result := NewClient(config)
+	require.Nil(t, result.Error, "Got %v", result.Error)
+	require.Equal(t, "example.com:80", result.Client.Dialer.FirstHop)
+	require.Equal(t, "example.com:53", result.Client.PacketListener.FirstHop)
+}
+
+func Test_NewTransport_Websocket(t *testing.T) {
+	config := `
+$parser: tcpudp
+tcp: &base
+    $parser: shadowsocks
+    endpoint: 
+        $parser: websocket
+        url: https://entrypoint.cdn.example.com/tcp
+    cipher: chacha20-ietf-poly1305
+    secret: SECRET
+udp:
+    <<: *base
+    endpoint: 
+        $parser: websocket
+        url: https://entrypoint.cdn.example.com/udp`
+	firstHop := "entrypoint.cdn.example.com:443"
+
+	result := NewClient(config)
+	require.Nil(t, result.Error, "Got %v", result.Error)
+	require.Equal(t, firstHop, result.Client.Dialer.FirstHop)
+	require.Equal(t, firstHop, result.Client.PacketListener.FirstHop)
+}
 
 func Test_NewClientFromJSON_Errors(t *testing.T) {
 	tests := []struct {