Feature: add lazy for proxy group and provider

adapters/outboundgroup/common.go

@@ -11,10 +11,14 @@ const (
 	defaultGetProxiesDuration = time.Second * 5
 )
 
-func getProvidersProxies(providers []provider.ProxyProvider) []C.Proxy {
+func getProvidersProxies(providers []provider.ProxyProvider, touch bool) []C.Proxy {
 	proxies := []C.Proxy{}
 	for _, provider := range providers {
-		proxies = append(proxies, provider.Proxies()...)
+		if touch {
+			proxies = append(proxies, provider.ProxiesWithTouch()...)
+		} else {
+			proxies = append(proxies, provider.Proxies()...)
+		}
 	}
 	return proxies
 }

adapters/outboundgroup/fallback.go

@@ -18,12 +18,12 @@ type Fallback struct {
 }
 
 func (f *Fallback) Now() string {
-	proxy := f.findAliveProxy()
+	proxy := f.findAliveProxy(false)
 	return proxy.Name()
 }
 
 func (f *Fallback) DialContext(ctx context.Context, metadata *C.Metadata) (C.Conn, error) {
-	proxy := f.findAliveProxy()
+	proxy := f.findAliveProxy(true)
 	c, err := proxy.DialContext(ctx, metadata)
 	if err == nil {
 		c.AppendToChains(f)
@@ -32,7 +32,7 @@ func (f *Fallback) DialContext(ctx context.Context, metadata *C.Metadata) (C.Con
 }
 
 func (f *Fallback) DialUDP(metadata *C.Metadata) (C.PacketConn, error) {
-	proxy := f.findAliveProxy()
+	proxy := f.findAliveProxy(true)
 	pc, err := proxy.DialUDP(metadata)
 	if err == nil {
 		pc.AppendToChains(f)
@@ -45,13 +45,13 @@ func (f *Fallback) SupportUDP() bool {
 		return false
 	}
 
-	proxy := f.findAliveProxy()
+	proxy := f.findAliveProxy(false)
 	return proxy.SupportUDP()
 }
 
 func (f *Fallback) MarshalJSON() ([]byte, error) {
 	var all []string
-	for _, proxy := range f.proxies() {
+	for _, proxy := range f.proxies(false) {
 		all = append(all, proxy.Name())
 	}
 	return json.Marshal(map[string]interface{}{
@@ -62,27 +62,27 @@ func (f *Fallback) MarshalJSON() ([]byte, error) {
 }
 
 func (f *Fallback) Unwrap(metadata *C.Metadata) C.Proxy {
-	proxy := f.findAliveProxy()
+	proxy := f.findAliveProxy(true)
 	return proxy
 }
 
-func (f *Fallback) proxies() []C.Proxy {
+func (f *Fallback) proxies(touch bool) []C.Proxy {
 	elm, _, _ := f.single.Do(func() (interface{}, error) {
-		return getProvidersProxies(f.providers), nil
+		return getProvidersProxies(f.providers, touch), nil
 	})
 
 	return elm.([]C.Proxy)
 }
 
-func (f *Fallback) findAliveProxy() C.Proxy {
+func (f *Fallback) findAliveProxy(touch bool) C.Proxy {
-	proxies := f.proxies()
+	proxies := f.proxies(touch)
 	for _, proxy := range proxies {
 		if proxy.Alive() {
 			return proxy
 		}
 	}
 
-	return f.proxies()[0]
+	return proxies[0]
 }
 
 func NewFallback(options *GroupCommonOption, providers []provider.ProxyProvider) *Fallback {

adapters/outboundgroup/loadbalance.go

@@ -131,13 +131,13 @@ func strategyConsistentHashing() strategyFn {
 }
 
 func (lb *LoadBalance) Unwrap(metadata *C.Metadata) C.Proxy {
-	proxies := lb.proxies()
+	proxies := lb.proxies(true)
 	return lb.strategyFn(proxies, metadata)
 }
 
-func (lb *LoadBalance) proxies() []C.Proxy {
+func (lb *LoadBalance) proxies(touch bool) []C.Proxy {
 	elm, _, _ := lb.single.Do(func() (interface{}, error) {
-		return getProvidersProxies(lb.providers), nil
+		return getProvidersProxies(lb.providers, touch), nil
 	})
 
 	return elm.([]C.Proxy)
@@ -145,7 +145,7 @@ func (lb *LoadBalance) proxies() []C.Proxy {
 
 func (lb *LoadBalance) MarshalJSON() ([]byte, error) {
 	var all []string
-	for _, proxy := range lb.proxies() {
+	for _, proxy := range lb.proxies(false) {
 		all = append(all, proxy.Name())
 	}
 	return json.Marshal(map[string]interface{}{

adapters/outboundgroup/parser.go

@@ -24,13 +24,16 @@ type GroupCommonOption struct {
 	Use        []string `group:"use,omitempty"`
 	URL        string   `group:"url,omitempty"`
 	Interval   int      `group:"interval,omitempty"`
+	Lazy       bool     `group:"lazy,omitempty"`
 	DisableUDP bool     `group:"disable-udp,omitempty"`
 }
 
 func ParseProxyGroup(config map[string]interface{}, proxyMap map[string]C.Proxy, providersMap map[string]provider.ProxyProvider) (C.ProxyAdapter, error) {
 	decoder := structure.NewDecoder(structure.Option{TagName: "group", WeaklyTypedInput: true})
 
-	groupOption := &GroupCommonOption{}
+	groupOption := &GroupCommonOption{
+		Lazy: true,
+	}
 	if err := decoder.Decode(config, groupOption); err != nil {
 		return nil, errFormat
 	}
@@ -55,7 +58,7 @@ func ParseProxyGroup(config map[string]interface{}, proxyMap map[string]C.Proxy,
 
 		// if Use not empty, drop health check options
 		if len(groupOption.Use) != 0 {
-			hc := provider.NewHealthCheck(ps, "", 0)
+			hc := provider.NewHealthCheck(ps, "", 0, true)
 			pd, err := provider.NewCompatibleProvider(groupName, ps, hc)
 			if err != nil {
 				return nil, err
@@ -69,7 +72,7 @@ func ParseProxyGroup(config map[string]interface{}, proxyMap map[string]C.Proxy,
 
 			// select don't need health check
 			if groupOption.Type == "select" || groupOption.Type == "relay" {
-				hc := provider.NewHealthCheck(ps, "", 0)
+				hc := provider.NewHealthCheck(ps, "", 0, true)
 				pd, err := provider.NewCompatibleProvider(groupName, ps, hc)
 				if err != nil {
 					return nil, err
@@ -82,7 +85,7 @@ func ParseProxyGroup(config map[string]interface{}, proxyMap map[string]C.Proxy,
 					return nil, errMissHealthCheck
 				}
 
-				hc := provider.NewHealthCheck(ps, groupOption.URL, uint(groupOption.Interval))
+				hc := provider.NewHealthCheck(ps, groupOption.URL, uint(groupOption.Interval), groupOption.Lazy)
 				pd, err := provider.NewCompatibleProvider(groupName, ps, hc)
 				if err != nil {
 					return nil, err

adapters/outboundgroup/relay.go

@@ -20,7 +20,7 @@ type Relay struct {
 }
 
 func (r *Relay) DialContext(ctx context.Context, metadata *C.Metadata) (C.Conn, error) {
-	proxies := r.proxies(metadata)
+	proxies := r.proxies(metadata, true)
 	if len(proxies) == 0 {
 		return nil, errors.New("proxy does not exist")
 	}
@@ -58,7 +58,7 @@ func (r *Relay) DialContext(ctx context.Context, metadata *C.Metadata) (C.Conn,
 
 func (r *Relay) MarshalJSON() ([]byte, error) {
 	var all []string
-	for _, proxy := range r.rawProxies() {
+	for _, proxy := range r.rawProxies(false) {
 		all = append(all, proxy.Name())
 	}
 	return json.Marshal(map[string]interface{}{
@@ -67,16 +67,16 @@ func (r *Relay) MarshalJSON() ([]byte, error) {
 	})
 }
 
-func (r *Relay) rawProxies() []C.Proxy {
+func (r *Relay) rawProxies(touch bool) []C.Proxy {
 	elm, _, _ := r.single.Do(func() (interface{}, error) {
-		return getProvidersProxies(r.providers), nil
+		return getProvidersProxies(r.providers, touch), nil
 	})
 
 	return elm.([]C.Proxy)
 }
 
-func (r *Relay) proxies(metadata *C.Metadata) []C.Proxy {
+func (r *Relay) proxies(metadata *C.Metadata, touch bool) []C.Proxy {
-	proxies := r.rawProxies()
+	proxies := r.rawProxies(touch)
 
 	for n, proxy := range proxies {
 		subproxy := proxy.Unwrap(metadata)

adapters/outboundgroup/selector.go

@@ -20,7 +20,7 @@ type Selector struct {
 }
 
 func (s *Selector) DialContext(ctx context.Context, metadata *C.Metadata) (C.Conn, error) {
-	c, err := s.selectedProxy().DialContext(ctx, metadata)
+	c, err := s.selectedProxy(true).DialContext(ctx, metadata)
 	if err == nil {
 		c.AppendToChains(s)
 	}
@@ -28,7 +28,7 @@ func (s *Selector) DialContext(ctx context.Context, metadata *C.Metadata) (C.Con
 }
 
 func (s *Selector) DialUDP(metadata *C.Metadata) (C.PacketConn, error) {
-	pc, err := s.selectedProxy().DialUDP(metadata)
+	pc, err := s.selectedProxy(true).DialUDP(metadata)
 	if err == nil {
 		pc.AppendToChains(s)
 	}
@@ -40,12 +40,12 @@ func (s *Selector) SupportUDP() bool {
 		return false
 	}
 
-	return s.selectedProxy().SupportUDP()
+	return s.selectedProxy(false).SupportUDP()
 }
 
 func (s *Selector) MarshalJSON() ([]byte, error) {
 	var all []string
-	for _, proxy := range getProvidersProxies(s.providers) {
+	for _, proxy := range getProvidersProxies(s.providers, false) {
 		all = append(all, proxy.Name())
 	}
 
@@ -57,11 +57,11 @@ func (s *Selector) MarshalJSON() ([]byte, error) {
 }
 
 func (s *Selector) Now() string {
-	return s.selectedProxy().Name()
+	return s.selectedProxy(false).Name()
 }
 
 func (s *Selector) Set(name string) error {
-	for _, proxy := range getProvidersProxies(s.providers) {
+	for _, proxy := range getProvidersProxies(s.providers, false) {
 		if proxy.Name() == name {
 			s.selected = name
 			s.single.Reset()
@@ -73,12 +73,12 @@ func (s *Selector) Set(name string) error {
 }
 
 func (s *Selector) Unwrap(metadata *C.Metadata) C.Proxy {
-	return s.selectedProxy()
+	return s.selectedProxy(true)
 }
 
-func (s *Selector) selectedProxy() C.Proxy {
+func (s *Selector) selectedProxy(touch bool) C.Proxy {
 	elm, _, _ := s.single.Do(func() (interface{}, error) {
-		proxies := getProvidersProxies(s.providers)
+		proxies := getProvidersProxies(s.providers, touch)
 		for _, proxy := range proxies {
 			if proxy.Name() == s.selected {
 				return proxy, nil

adapters/outboundgroup/urltest.go

@@ -30,11 +30,11 @@ type URLTest struct {
 }
 
 func (u *URLTest) Now() string {
-	return u.fast().Name()
+	return u.fast(false).Name()
 }
 
 func (u *URLTest) DialContext(ctx context.Context, metadata *C.Metadata) (c C.Conn, err error) {
-	c, err = u.fast().DialContext(ctx, metadata)
+	c, err = u.fast(true).DialContext(ctx, metadata)
 	if err == nil {
 		c.AppendToChains(u)
 	}
@@ -42,7 +42,7 @@ func (u *URLTest) DialContext(ctx context.Context, metadata *C.Metadata) (c C.Co
 }
 
 func (u *URLTest) DialUDP(metadata *C.Metadata) (C.PacketConn, error) {
-	pc, err := u.fast().DialUDP(metadata)
+	pc, err := u.fast(true).DialUDP(metadata)
 	if err == nil {
 		pc.AppendToChains(u)
 	}
@@ -50,20 +50,20 @@ func (u *URLTest) DialUDP(metadata *C.Metadata) (C.PacketConn, error) {
 }
 
 func (u *URLTest) Unwrap(metadata *C.Metadata) C.Proxy {
-	return u.fast()
+	return u.fast(true)
 }
 
-func (u *URLTest) proxies() []C.Proxy {
+func (u *URLTest) proxies(touch bool) []C.Proxy {
 	elm, _, _ := u.single.Do(func() (interface{}, error) {
-		return getProvidersProxies(u.providers), nil
+		return getProvidersProxies(u.providers, touch), nil
 	})
 
 	return elm.([]C.Proxy)
 }
 
-func (u *URLTest) fast() C.Proxy {
+func (u *URLTest) fast(touch bool) C.Proxy {
 	elm, _, _ := u.fastSingle.Do(func() (interface{}, error) {
-		proxies := u.proxies()
+		proxies := u.proxies(touch)
 		fast := proxies[0]
 		min := fast.LastDelay()
 		for _, proxy := range proxies[1:] {
@@ -94,12 +94,12 @@ func (u *URLTest) SupportUDP() bool {
 		return false
 	}
 
-	return u.fast().SupportUDP()
+	return u.fast(false).SupportUDP()
 }
 
 func (u *URLTest) MarshalJSON() ([]byte, error) {
 	var all []string
-	for _, proxy := range u.proxies() {
+	for _, proxy := range u.proxies(false) {
 		all = append(all, proxy.Name())
 	}
 	return json.Marshal(map[string]interface{}{

adapters/provider/healthcheck.go

@@ -5,6 +5,8 @@ import (
 	"time"
 
 	C "github.com/Dreamacro/clash/constant"
+
+	"go.uber.org/atomic"
 )
 
 const (
@@ -17,10 +19,12 @@ type HealthCheckOption struct {
 }
 
 type HealthCheck struct {
-	url      string
+	url       string
-	proxies  []C.Proxy
+	proxies   []C.Proxy
-	interval uint
+	interval  uint
-	done     chan struct{}
+	lazy      bool
+	lastTouch *atomic.Int64
+	done      chan struct{}
 }
 
 func (hc *HealthCheck) process() {
@@ -30,7 +34,10 @@ func (hc *HealthCheck) process() {
 	for {
 		select {
 		case <-ticker.C:
-			hc.check()
+			now := time.Now().Unix()
+			if !hc.lazy || now-hc.lastTouch.Load() < int64(hc.interval) {
+				hc.check()
+			}
 		case <-hc.done:
 			ticker.Stop()
 			return
@@ -46,6 +53,10 @@ func (hc *HealthCheck) auto() bool {
 	return hc.interval != 0
 }
 
+func (hc *HealthCheck) touch() {
+	hc.lastTouch.Store(time.Now().Unix())
+}
+
 func (hc *HealthCheck) check() {
 	ctx, cancel := context.WithTimeout(context.Background(), defaultURLTestTimeout)
 	for _, proxy := range hc.proxies {
@@ -60,11 +71,13 @@ func (hc *HealthCheck) close() {
 	hc.done <- struct{}{}
 }
 
-func NewHealthCheck(proxies []C.Proxy, url string, interval uint) *HealthCheck {
+func NewHealthCheck(proxies []C.Proxy, url string, interval uint, lazy bool) *HealthCheck {
 	return &HealthCheck{
-		proxies:  proxies,
+		proxies:   proxies,
-		url:      url,
+		url:       url,
-		interval: interval,
+		interval:  interval,
-		done:     make(chan struct{}, 1),
+		lazy:      lazy,
+		lastTouch: atomic.NewInt64(0),
+		done:      make(chan struct{}, 1),
 	}
 }

adapters/provider/parser.go

@@ -17,6 +17,7 @@ type healthCheckSchema struct {
 	Enable   bool   `provider:"enable"`
 	URL      string `provider:"url"`
 	Interval int    `provider:"interval"`
+	Lazy     bool   `provider:"lazy,omitempty"`
 }
 
 type proxyProviderSchema struct {
@@ -30,7 +31,11 @@ type proxyProviderSchema struct {
 func ParseProxyProvider(name string, mapping map[string]interface{}) (ProxyProvider, error) {
 	decoder := structure.NewDecoder(structure.Option{TagName: "provider", WeaklyTypedInput: true})
 
-	schema := &proxyProviderSchema{}
+	schema := &proxyProviderSchema{
+		HealthCheck: healthCheckSchema{
+			Lazy: true,
+		},
+	}
 	if err := decoder.Decode(mapping, schema); err != nil {
 		return nil, err
 	}
@@ -39,7 +44,7 @@ func ParseProxyProvider(name string, mapping map[string]interface{}) (ProxyProvi
 	if schema.HealthCheck.Enable {
 		hcInterval = uint(schema.HealthCheck.Interval)
 	}
-	hc := NewHealthCheck([]C.Proxy{}, schema.HealthCheck.URL, hcInterval)
+	hc := NewHealthCheck([]C.Proxy{}, schema.HealthCheck.URL, hcInterval, schema.HealthCheck.Lazy)
 
 	path := C.Path.Resolve(schema.Path)
 

adapters/provider/provider.go

@@ -50,6 +50,9 @@ type Provider interface {
 type ProxyProvider interface {
 	Provider
 	Proxies() []C.Proxy
+	// ProxiesWithTouch is used to inform the provider that the proxy is actually being used while getting the list of proxies.
+	// Commonly used in Dial and DialUDP
+	ProxiesWithTouch() []C.Proxy
 	HealthCheck()
 }
 
@@ -112,6 +115,11 @@ func (pp *proxySetProvider) Proxies() []C.Proxy {
 	return pp.proxies
 }
 
+func (pp *proxySetProvider) ProxiesWithTouch() []C.Proxy {
+	pp.healthCheck.touch()
+	return pp.Proxies()
+}
+
 func proxiesParse(buf []byte) (interface{}, error) {
 	schema := &ProxySchema{}
 
@@ -223,6 +231,11 @@ func (cp *compatibleProvider) Proxies() []C.Proxy {
 	return cp.proxies
 }
 
+func (cp *compatibleProvider) ProxiesWithTouch() []C.Proxy {
+	cp.healthCheck.touch()
+	return cp.Proxies()
+}
+
 func stopCompatibleProvider(pd *CompatibleProvider) {
 	pd.healthCheck.close()
 }

config/config.go

@@ -345,7 +345,7 @@ func parseProxies(cfg *RawConfig) (proxies map[string]C.Proxy, providersMap map[
 	for _, v := range proxyList {
 		ps = append(ps, proxies[v])
 	}
-	hc := provider.NewHealthCheck(ps, "", 0)
+	hc := provider.NewHealthCheck(ps, "", 0, true)
 	pd, _ := provider.NewCompatibleProvider(provider.ReservedName, ps, hc)
 	providersMap[provider.ReservedName] = pd