prometheus/vendor/github.com/docker/go-connections/sockets/inmem_socket.go
Julien Pivotto 59de58d380
Docker Swarm service discovery (#7420)
* Docker Swarm service discovery

Signed-off-by: Julien Pivotto <roidelapluie@inuits.eu>
2020-06-26 12:25:58 +02:00

82 lines
1.9 KiB
Go

package sockets
import (
"errors"
"net"
"sync"
)
var errClosed = errors.New("use of closed network connection")
// InmemSocket implements net.Listener using in-memory only connections.
type InmemSocket struct {
chConn chan net.Conn
chClose chan struct{}
addr string
mu sync.Mutex
}
// dummyAddr is used to satisfy net.Addr for the in-mem socket
// it is just stored as a string and returns the string for all calls
type dummyAddr string
// NewInmemSocket creates an in-memory only net.Listener
// The addr argument can be any string, but is used to satisfy the `Addr()` part
// of the net.Listener interface
func NewInmemSocket(addr string, bufSize int) *InmemSocket {
return &InmemSocket{
chConn: make(chan net.Conn, bufSize),
chClose: make(chan struct{}),
addr: addr,
}
}
// Addr returns the socket's addr string to satisfy net.Listener
func (s *InmemSocket) Addr() net.Addr {
return dummyAddr(s.addr)
}
// Accept implements the Accept method in the Listener interface; it waits for the next call and returns a generic Conn.
func (s *InmemSocket) Accept() (net.Conn, error) {
select {
case conn := <-s.chConn:
return conn, nil
case <-s.chClose:
return nil, errClosed
}
}
// Close closes the listener. It will be unavailable for use once closed.
func (s *InmemSocket) Close() error {
s.mu.Lock()
defer s.mu.Unlock()
select {
case <-s.chClose:
default:
close(s.chClose)
}
return nil
}
// Dial is used to establish a connection with the in-mem server
func (s *InmemSocket) Dial(network, addr string) (net.Conn, error) {
srvConn, clientConn := net.Pipe()
select {
case s.chConn <- srvConn:
case <-s.chClose:
return nil, errClosed
}
return clientConn, nil
}
// Network returns the addr string, satisfies net.Addr
func (a dummyAddr) Network() string {
return string(a)
}
// String returns the string form
func (a dummyAddr) String() string {
return string(a)
}