refactor: separate auth config from runtime and defer token resolution (#5105)

pkg/auth/auth.go

@@ -15,6 +15,7 @@
 package auth
 
 import (
+	"context"
 	"fmt"
 
 	v1 "github.com/fatedier/frp/pkg/config/v1"
@@ -27,6 +28,39 @@ type Setter interface {
 	SetNewWorkConn(*msg.NewWorkConn) error
 }
 
+type ClientAuth struct {
+	Setter Setter
+	key    []byte
+}
+
+func (a *ClientAuth) EncryptionKey() []byte {
+	return a.key
+}
+
+// BuildClientAuth resolves any dynamic auth values and returns a prepared auth runtime.
+// Caller must run validation before calling this function.
+func BuildClientAuth(cfg *v1.AuthClientConfig) (*ClientAuth, error) {
+	if cfg == nil {
+		return nil, fmt.Errorf("auth config is nil")
+	}
+	resolved := *cfg
+	if resolved.Method == v1.AuthMethodToken && resolved.TokenSource != nil {
+		token, err := resolved.TokenSource.Resolve(context.Background())
+		if err != nil {
+			return nil, fmt.Errorf("failed to resolve auth.tokenSource: %w", err)
+		}
+		resolved.Token = token
+	}
+	setter, err := NewAuthSetter(resolved)
+	if err != nil {
+		return nil, err
+	}
+	return &ClientAuth{
+		Setter: setter,
+		key:    []byte(resolved.Token),
+	}, nil
+}
+
 func NewAuthSetter(cfg v1.AuthClientConfig) (authProvider Setter, err error) {
 	switch cfg.Method {
 	case v1.AuthMethodToken:
@@ -52,6 +86,35 @@ type Verifier interface {
 	VerifyNewWorkConn(*msg.NewWorkConn) error
 }
 
+type ServerAuth struct {
+	Verifier Verifier
+	key      []byte
+}
+
+func (a *ServerAuth) EncryptionKey() []byte {
+	return a.key
+}
+
+// BuildServerAuth resolves any dynamic auth values and returns a prepared auth runtime.
+// Caller must run validation before calling this function.
+func BuildServerAuth(cfg *v1.AuthServerConfig) (*ServerAuth, error) {
+	if cfg == nil {
+		return nil, fmt.Errorf("auth config is nil")
+	}
+	resolved := *cfg
+	if resolved.Method == v1.AuthMethodToken && resolved.TokenSource != nil {
+		token, err := resolved.TokenSource.Resolve(context.Background())
+		if err != nil {
+			return nil, fmt.Errorf("failed to resolve auth.tokenSource: %w", err)
+		}
+		resolved.Token = token
+	}
+	return &ServerAuth{
+		Verifier: NewAuthVerifier(resolved),
+		key:      []byte(resolved.Token),
+	}, nil
+}
+
 func NewAuthVerifier(cfg v1.AuthServerConfig) (authVerifier Verifier) {
 	switch cfg.Method {
 	case v1.AuthMethodToken: