add plugin system

auth/plugin.go

@@ -0,0 +1,58 @@
+package auth
+
+import (
+	"context"
+
+	"github.com/go-gost/core/auth"
+	"github.com/go-gost/plugin/auth/proto"
+	xlogger "github.com/go-gost/x/logger"
+)
+
+type pluginAuthenticator struct {
+	client  proto.AuthenticatorClient
+	options options
+}
+
+// NewPluginAuthenticator creates an Authenticator that authenticates client by plugin.
+func NewPluginAuthenticator(opts ...Option) auth.Authenticator {
+	var options options
+	for _, opt := range opts {
+		opt(&options)
+	}
+	if options.logger == nil {
+		options.logger = xlogger.Nop()
+	}
+
+	p := &pluginAuthenticator{
+		options: options,
+	}
+	if options.client != nil {
+		p.client = proto.NewAuthenticatorClient(options.client)
+	}
+	return p
+}
+
+// Authenticate checks the validity of the provided user-password pair.
+func (p *pluginAuthenticator) Authenticate(ctx context.Context, user, password string) bool {
+	if p.client == nil {
+		return false
+	}
+
+	r, err := p.client.Authenticate(ctx,
+		&proto.AuthenticateRequest{
+			Username: user,
+			Password: password,
+		})
+	if err != nil {
+		p.options.logger.Error(err)
+		return false
+	}
+	return r.Ok
+}
+
+func (p *pluginAuthenticator) Close() error {
+	if p.options.client != nil {
+		return p.options.client.Close()
+	}
+	return nil
+}