/*
使用了第三方 github.com/armon/go-proxyproto 包
@todo 两次调用了 ln.Close() 为什么不会引发问题？
defer ln.Close()
// close the socket on exit to terminate the accept loop
go func() {
<-quit
ln.Close()
}()
*/
func listenAndServeTCP(l config.Listen, h proxy.TCPProxy) {
log.Print("[INFO] TCP+SNI proxy listening on ", l.Addr)
// 生成 Listener 结构体类型
ln, err := net.Listen("tcp", l.Addr)
if err != nil {
exit.Fatal("[FATAL] ", err)
}
ln = &proxyproto.Listener{Listener: tcpKeepAliveListener{ln.(*net.TCPListener)}}
defer ln.Close()
// close the socket on exit to terminate the accept loop
go func() {
<-quit
ln.Close()
}()
for {
// 接收连接请求
conn, err := ln.Accept()
if err != nil {
select {
case <-quit:
return
default:
exit.Fatal("[FATAL] ", err)
}
}
// 处理连接
go h.Serve(conn)
}
}
func listenAndServe(l config.Listen, h http.Handler) {
srv := &http.Server{
Handler: h,
Addr: l.Addr,
ReadTimeout: l.ReadTimeout,
WriteTimeout: l.WriteTimeout,
}
if l.Scheme == "https" {
src, err := cert.NewSource(l.CertSource)
if err != nil {
exit.Fatal("[FATAL] ", err)
}
srv.TLSConfig, err = cert.TLSConfig(src)
if err != nil {
exit.Fatal("[FATAL] ", err)
}
}
if srv.TLSConfig != nil {
log.Printf("[INFO] HTTPS proxy listening on %s", l.Addr)
if srv.TLSConfig.ClientAuth == tls.RequireAndVerifyClientCert {
log.Printf("[INFO] Client certificate authentication enabled on %s", l.Addr)
}
} else {
log.Printf("[INFO] HTTP proxy listening on %s", l.Addr)
}
if err := serve(srv); err != nil {
exit.Fatal("[FATAL] ", err)
}
}
func initMetrics(cfg *config.Config) {
if cfg.Metrics.Target == "" {
log.Printf("[INFO] Metrics disabled")
return
}
var err error
if metrics.DefaultRegistry, err = metrics.NewRegistry(cfg.Metrics); err != nil {
exit.Fatal("[FATAL] ", err)
}
if route.ServiceRegistry, err = metrics.NewRegistry(cfg.Metrics); err != nil {
exit.Fatal("[FATAL] ", err)
}
}
// NewRegistry creates a new metrics registry.
func NewRegistry(cfg config.Metrics) (r Registry, err error) {
if prefix, err = parsePrefix(cfg.Prefix); err != nil {
return nil, fmt.Errorf("metrics: invalid Prefix template. %s", err)
}
if names, err = parseNames(cfg.Names); err != nil {
return nil, fmt.Errorf("metrics: invalid names template. %s", err)
}
switch cfg.Target {
case "stdout":
log.Printf("[INFO] Sending metrics to stdout")
return gmStdoutRegistry(cfg.Interval)
case "graphite":
log.Printf("[INFO] Sending metrics to Graphite on %s as %q", cfg.GraphiteAddr, prefix)
return gmGraphiteRegistry(prefix, cfg.GraphiteAddr, cfg.Interval)
case "statsd":
log.Printf("[INFO] Sending metrics to StatsD on %s as %q", cfg.StatsDAddr, prefix)
return gmStatsDRegistry(prefix, cfg.StatsDAddr, cfg.Interval)
case "circonus":
return circonusRegistry(prefix, cfg.Circonus, cfg.Interval)
default:
exit.Fatal("[FATAL] Invalid metrics target ", cfg.Target)
}
panic("unreachable")
}
func defaultPrefix() string {
host, err := hostname()
if err != nil {
exit.Fatal("[FATAL] ", err)
}
exe := filepath.Base(os.Args[0])
return clean(host) + "." + clean(exe)
}
func startAdmin(cfg *config.Config) {
log.Printf("[INFO] Admin server listening on %q", cfg.UI.Addr)
go func() {
if err := admin.ListenAndServe(cfg, version); err != nil {
exit.Fatal("[FATAL] ui: ", err)
}
}()
}
func initBackend(cfg *config.Config) {
var err error
switch cfg.Registry.Backend {
case "file":
registry.Default, err = file.NewBackend(cfg.Registry.File.Path)
case "static":
registry.Default, err = static.NewBackend(cfg.Registry.Static.Routes)
case "consul":
registry.Default, err = consul.NewBackend(&cfg.Registry.Consul)
default:
exit.Fatal("[FATAL] Unknown registry backend ", cfg.Registry.Backend)
}
if err != nil {
exit.Fatal("[FATAL] Error initializing backend. ", err)
}
if err := registry.Default.Register(); err != nil {
exit.Fatal("[FATAL] Error registering backend. ", err)
}
}
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)
}
func serve(srv *http.Server) error {
ln, err := net.Listen("tcp", srv.Addr)
if err != nil {
exit.Fatal("[FATAL] ", err)
}
ln = &proxyproto.Listener{Listener: tcpKeepAliveListener{ln.(*net.TCPListener)}}
if srv.TLSConfig != nil {
ln = tls.NewListener(ln, srv.TLSConfig)
}
return srv.Serve(ln)
}
/**
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 Init(cfg config.Metrics) error {
pfx = cfg.Prefix
if pfx == "default" {
pfx = defaultPrefix()
}
switch cfg.Target {
case "stdout":
log.Printf("[INFO] Sending metrics to stdout")
return initStdout(cfg.Interval)
case "graphite":
if cfg.GraphiteAddr == "" {
return errors.New("metrics: graphite addr missing")
}
log.Printf("[INFO] Sending metrics to Graphite on %s as %q", cfg.GraphiteAddr, pfx)
return initGraphite(cfg.GraphiteAddr, cfg.Interval)
case "":
log.Printf("[INFO] Metrics disabled")
default:
exit.Fatal("[FATAL] Invalid metrics target ", cfg.Target)
}
return nil
}
func initMetrics(cfg *config.Config) {
if err := metrics.Init(cfg.Metrics); err != nil {
exit.Fatal("[FATAL] ", err)
}
}