func newHTTPProxy(cfg *config.Config) http.Handler {
if err := route.SetPickerStrategy(cfg.Proxy.Strategy); err != nil {
exit.Fatal("[FATAL] ", err)
}
log.Printf("[INFO] Using routing strategy %q", cfg.Proxy.Strategy)
if err := route.SetMatcher(cfg.Proxy.Matcher); err != nil {
exit.Fatal("[FATAL] ", err)
}
log.Printf("[INFO] Using routing matching %q", cfg.Proxy.Matcher)
tr := &http.Transport{
ResponseHeaderTimeout: cfg.Proxy.ResponseHeaderTimeout,
MaxIdleConnsPerHost: cfg.Proxy.MaxConn,
Dial: (&net.Dialer{
Timeout: cfg.Proxy.DialTimeout,
KeepAlive: cfg.Proxy.KeepAliveTimeout,
}).Dial,
}
return proxy.NewHTTPProxy(tr, cfg.Proxy)
}
/**
使用配置信息创建并返回HTTP代理服务器的句柄
*/
func newHTTPProxy(cfg *config.Config) http.Handler {
// 设置路由拣选策略
if err := route.SetPickerStrategy(cfg.Proxy.Strategy); err != nil {
exit.Fatal("[FATAL] ", err)
}
log.Printf("[INFO] Using routing strategy %q", cfg.Proxy.Strategy)
// 设置路由匹配器
if err := route.SetMatcher(cfg.Proxy.Matcher); err != nil {
exit.Fatal("[FATAL] ", err)
}
log.Printf("[INFO] Using routing matching %q", cfg.Proxy.Matcher)
// 配置转换器
tr := &http.Transport{
ResponseHeaderTimeout: cfg.Proxy.ResponseHeaderTimeout,
MaxIdleConnsPerHost: cfg.Proxy.MaxConn,
Dial: (&net.Dialer{
Timeout: cfg.Proxy.DialTimeout,
KeepAlive: cfg.Proxy.KeepAliveTimeout,
}).Dial,
}
/**
@todo 上面代码中有疑问，如下代码：
Dial: (&net.Dialer{
Timeout: cfg.Proxy.DialTimeout,
KeepAlive: cfg.Proxy.KeepAliveTimeout,
}).Dial
第一行为何用 &net.Dialer ? 即为何使用引用？
原因是 net包的Dialer结构体(struct)的方法Dial是指针类型，所以只有使用引用定义的时候才能访问到该函数
*/
// 生成并返回HTTP代理句柄
return proxy.NewHTTPProxy(tr, cfg.Proxy)
}
func TestGracefulShutdown(t *testing.T) {
req := func(url string) int {
resp, err := http.Get(url)
if err != nil {
t.Fatal(err)
}
defer resp.Body.Close()
return resp.StatusCode
}
// start a server which responds after the shutdown has been triggered.
srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
<-quit // wait for shutdown signal
return
}))
defer srv.Close()
// load the routing table
tbl, err := route.ParseString("route add svc / " + srv.URL)
if err != nil {
t.Fatal(err)
}
route.SetTable(tbl)
// start proxy with graceful shutdown period long enough
// to complete one more request.
var wg sync.WaitGroup
l := config.Listen{Addr: "127.0.0.1:57777", Proto: "http"}
wg.Add(1)
go func() {
defer wg.Done()
startListeners([]config.Listen{l}, 250*time.Millisecond, proxy.NewHTTPProxy(http.DefaultTransport, config.Proxy{}), nil)
}()
// trigger shutdown after some time
shutdownDelay := 100 * time.Millisecond
go func() {
time.Sleep(shutdownDelay)
close(quit)
}()
// give proxy some time to start up
// needs to be done before shutdown is triggered
time.Sleep(shutdownDelay / 2)
// make 200 OK request
// start before and complete after shutdown was triggered
if got, want := req("http://"+l.Addr+"/"), 200; got != want {
t.Fatalf("request 1: got %v want %v", got, want)
}
// make 503 request
// start and complete after shutdown was triggered
if got, want := req("http://"+l.Addr+"/"), 503; got != want {
t.Fatalf("got %v want %v", got, want)
}
// wait for listen() to return
// note that the actual listeners have not returned yet
wg.Wait()
}