docker/pkg/listenbuffer/buffer.go

47 строки
1.1 KiB
Go

/*
Package to allow go applications to immediately start
listening on a socket, unix, tcp, udp but hold connections
until the application has booted and is ready to accept them
*/
package listenbuffer
import "net"
// NewListenBuffer returns a listener listening on addr with the protocol.
func NewListenBuffer(proto, addr string, activate chan struct{}) (net.Listener, error) {
wrapped, err := net.Listen(proto, addr)
if err != nil {
return nil, err
}
return &defaultListener{
wrapped: wrapped,
activate: activate,
}, nil
}
type defaultListener struct {
wrapped net.Listener // the real listener to wrap
ready bool // is the listner ready to start accpeting connections
activate chan struct{}
}
func (l *defaultListener) Close() error {
return l.wrapped.Close()
}
func (l *defaultListener) Addr() net.Addr {
return l.wrapped.Addr()
}
func (l *defaultListener) Accept() (net.Conn, error) {
// if the listen has been told it is ready then we can go ahead and
// start returning connections
if l.ready {
return l.wrapped.Accept()
}
<-l.activate
l.ready = true
return l.Accept()
}