initial commit

service/service.go

@@ -0,0 +1,120 @@
+package service
+
+import (
+	"context"
+	"net"
+	"time"
+
+	"github.com/go-gost/core/admission"
+	"github.com/go-gost/core/handler"
+	"github.com/go-gost/core/listener"
+	"github.com/go-gost/core/logger"
+	"github.com/go-gost/metrics"
+)
+
+type options struct {
+	admission admission.Admission
+	logger    logger.Logger
+}
+
+type Option func(opts *options)
+
+func AdmissionOption(admission admission.Admission) Option {
+	return func(opts *options) {
+		opts.admission = admission
+	}
+}
+
+func LoggerOption(logger logger.Logger) Option {
+	return func(opts *options) {
+		opts.logger = logger
+	}
+}
+
+type Service interface {
+	Serve() error
+	Addr() net.Addr
+	Close() error
+}
+
+type service struct {
+	name     string
+	listener listener.Listener
+	handler  handler.Handler
+	options  options
+}
+
+func NewService(name string, ln listener.Listener, h handler.Handler, opts ...Option) Service {
+	var options options
+	for _, opt := range opts {
+		opt(&options)
+	}
+	return &service{
+		name:     name,
+		listener: ln,
+		handler:  h,
+		options:  options,
+	}
+}
+
+func (s *service) Addr() net.Addr {
+	return s.listener.Addr()
+}
+
+func (s *service) Close() error {
+	return s.listener.Close()
+}
+
+func (s *service) Serve() error {
+	metrics.Services().Inc()
+	defer metrics.Services().Dec()
+
+	var tempDelay time.Duration
+	for {
+		conn, e := s.listener.Accept()
+		if e != nil {
+			if ne, ok := e.(net.Error); ok && ne.Temporary() {
+				if tempDelay == 0 {
+					tempDelay = 1 * time.Second
+				} else {
+					tempDelay *= 2
+				}
+				if max := 5 * time.Second; tempDelay > max {
+					tempDelay = max
+				}
+				s.options.logger.Warnf("accept: %v, retrying in %v", e, tempDelay)
+				time.Sleep(tempDelay)
+				continue
+			}
+			s.options.logger.Errorf("accept: %v", e)
+			return e
+		}
+		tempDelay = 0
+
+		if s.options.admission != nil &&
+			!s.options.admission.Admit(conn.RemoteAddr().String()) {
+			conn.Close()
+			continue
+		}
+
+		go func() {
+			metrics.Requests(s.name).Inc()
+
+			metrics.RequestsInFlight(s.name).Inc()
+			defer metrics.RequestsInFlight(s.name).Dec()
+
+			start := time.Now()
+			defer func() {
+				metrics.RequestSeconds(s.name).Observe(time.Since(start).Seconds())
+			}()
+
+			if err := s.handler.Handle(
+				context.Background(),
+				conn,
+			); err != nil {
+				s.options.logger.Error(err)
+				metrics.HandlerErrors(s.name).Inc()
+			}
+		}()
+	}
+}