Optimization: refactor picker

adapters/outbound/base.go

@@ -1,6 +1,7 @@
 package adapters
 
 import (
+	"context"
 	"encoding/json"
 	"errors"
 	"net"
@@ -99,7 +100,7 @@ func (p *Proxy) MarshalJSON() ([]byte, error) {
 }
 
 // URLTest get the delay for the specified URL
-func (p *Proxy) URLTest(url string) (t uint16, err error) {
+func (p *Proxy) URLTest(ctx context.Context, url string) (t uint16, err error) {
 	defer func() {
 		p.alive = err == nil
 		record := C.DelayHistory{Time: time.Now()}
@@ -123,6 +124,13 @@ func (p *Proxy) URLTest(url string) (t uint16, err error) {
 		return
 	}
 	defer instance.Close()
+
+	req, err := http.NewRequest(http.MethodGet, url, nil)
+	if err != nil {
+		return
+	}
+	req = req.WithContext(ctx)
+
 	transport := &http.Transport{
 		Dial: func(string, string) (net.Conn, error) {
 			return instance, nil
@@ -133,8 +141,9 @@ func (p *Proxy) URLTest(url string) (t uint16, err error) {
 		TLSHandshakeTimeout:   10 * time.Second,
 		ExpectContinueTimeout: 1 * time.Second,
 	}
+
 	client := http.Client{Transport: transport}
-	resp, err := client.Get(url)
+	resp, err := client.Do(req)
 	if err != nil {
 		return
 	}

adapters/outbound/fallback.go

@@ -1,6 +1,7 @@
 package adapters
 
 import (
+	"context"
 	"encoding/json"
 	"errors"
 	"net"
@@ -90,7 +91,7 @@ func (f *Fallback) validTest() {
 
 	for _, p := range f.proxies {
 		go func(p C.Proxy) {
-			p.URLTest(f.rawURL)
+			p.URLTest(context.Background(), f.rawURL)
 			wg.Done()
 		}(p)
 	}

adapters/outbound/loadbalance.go

@@ -1,6 +1,7 @@
 package adapters
 
 import (
+	"context"
 	"encoding/json"
 	"errors"
 	"net"
@@ -95,7 +96,7 @@ func (lb *LoadBalance) validTest() {
 
 	for _, p := range lb.proxies {
 		go func(p C.Proxy) {
-			p.URLTest(lb.rawURL)
+			p.URLTest(context.Background(), lb.rawURL)
 			wg.Done()
 		}(p)
 	}

adapters/outbound/urltest.go

@@ -5,7 +5,6 @@ import (
 	"encoding/json"
 	"errors"
 	"net"
-	"sync"
 	"sync/atomic"
 	"time"
 
@@ -103,35 +102,22 @@ func (u *URLTest) speedTest() {
 	}
 	defer atomic.StoreInt32(&u.once, 0)
 
-	wg := sync.WaitGroup{}
-	wg.Add(len(u.proxies))
-	c := make(chan interface{})
-	fast := picker.SelectFast(context.Background(), c)
-	timer := time.NewTimer(u.interval)
-
+	ctx, cancel := context.WithTimeout(context.Background(), u.interval)
+	defer cancel()
+	picker, ctx := picker.WithContext(ctx)
 	for _, p := range u.proxies {
-		go func(p C.Proxy) {
-			_, err := p.URLTest(u.rawURL)
-			if err == nil {
-				c <- p
+		picker.Go(func() (interface{}, error) {
+			_, err := p.URLTest(ctx, u.rawURL)
+			if err != nil {
+				return nil, err
 			}
-			wg.Done()
-		}(p)
+			return p, nil
+		})
 	}
 
-	go func() {
-		wg.Wait()
-		close(c)
-	}()
-
-	select {
-	case <-timer.C:
-		// Wait for fast to return or close.
-		<-fast
-	case p, open := <-fast:
-		if open {
-			u.fast = p.(C.Proxy)
-		}
+	fast := picker.Wait()
+	if fast != nil {
+		u.fast = fast.(C.Proxy)
 	}
 }