// watchHandler watches w and keeps *resourceVersion up to date.
func (r *Reflector) watchHandler(w watch.Interface, resourceVersion *string, resyncCh <-chan time.Time, stopCh <-chan struct{}) error {
start := time.Now()
eventCount := 0
// Stopping the watcher should be idempotent and if we return from this function there's no way
// we're coming back in with the same watch interface.
defer w.Stop()
loop:
for {
select {
case <-stopCh:
return errorStopRequested
case <-resyncCh:
return errorResyncRequested
case event, ok := <-w.ResultChan():
if !ok {
break loop
}
if event.Type == watch.Error {
return apierrs.FromObject(event.Object)
}
if e, a := r.expectedType, reflect.TypeOf(event.Object); e != nil && e != a {
util.HandleError(fmt.Errorf("%s: expected type %v, but watch event object had type %v", r.name, e, a))
continue
}
meta, err := meta.Accessor(event.Object)
if err != nil {
util.HandleError(fmt.Errorf("%s: unable to understand watch event %#v", r.name, event))
continue
}
newResourceVersion := meta.ResourceVersion()
switch event.Type {
case watch.Added:
r.store.Add(event.Object)
case watch.Modified:
r.store.Update(event.Object)
case watch.Deleted:
// TODO: Will any consumers need access to the "last known
// state", which is passed in event.Object? If so, may need
// to change this.
r.store.Delete(event.Object)
default:
util.HandleError(fmt.Errorf("%s: unable to understand watch event %#v", r.name, event))
}
*resourceVersion = newResourceVersion
r.setLastSyncResourceVersion(newResourceVersion)
eventCount++
}
}
watchDuration := time.Now().Sub(start)
if watchDuration < 1*time.Second && eventCount == 0 {
glog.V(4).Infof("%s: Unexpected watch close - watch lasted less than a second and no items received", r.name)
return errors.New("very short watch")
}
glog.V(4).Infof("%s: Watch close - %v total %v items received", r.name, r.expectedType, eventCount)
return nil
}
// forward dials the remote host specific in req, upgrades the request, starts
// listeners for each port specified in ports, and forwards local connections
// to the remote host via streams.
func (pf *PortForwarder) forward() error {
var err error
listenSuccess := false
for _, port := range pf.ports {
err = pf.listenOnPort(&port)
switch {
case err == nil:
listenSuccess = true
default:
glog.Warningf("Unable to listen on port %d: %v", port.Local, err)
}
}
if !listenSuccess {
return fmt.Errorf("Unable to listen on any of the requested ports: %v", pf.ports)
}
close(pf.Ready)
// wait for interrupt or conn closure
select {
case <-pf.stopChan:
case <-pf.streamConn.CloseChan():
util.HandleError(errors.New("lost connection to pod"))
}
return nil
}
func (pf *PortForwarder) Close() {
// stop all listeners
for _, l := range pf.listeners {
if err := l.Close(); err != nil {
util.HandleError(fmt.Errorf("error closing listener: %v", err))
}
}
}
// Returns error if ListAndWatch didn't even tried to initialize watch.
func (r *Reflector) ListAndWatch(stopCh <-chan struct{}) error {
var resourceVersion string
resyncCh, cleanup := r.resyncChan()
defer cleanup()
list, err := r.listerWatcher.List()
if err != nil {
return fmt.Errorf("%s: Failed to list %v: %v", r.name, r.expectedType, err)
}
meta, err := meta.Accessor(list)
if err != nil {
return fmt.Errorf("%s: Unable to understand list result %#v", r.name, list)
}
resourceVersion = meta.ResourceVersion()
items, err := runtime.ExtractList(list)
if err != nil {
return fmt.Errorf("%s: Unable to understand list result %#v (%v)", r.name, list, err)
}
if err := r.syncWith(items, resourceVersion); err != nil {
return fmt.Errorf("%s: Unable to sync list result: %v", r.name, err)
}
r.setLastSyncResourceVersion(resourceVersion)
for {
w, err := r.listerWatcher.Watch(resourceVersion)
if err != nil {
switch err {
case io.EOF:
// watch closed normally
case io.ErrUnexpectedEOF:
glog.V(1).Infof("%s: Watch for %v closed with unexpected EOF: %v", r.name, r.expectedType, err)
default:
util.HandleError(fmt.Errorf("%s: Failed to watch %v: %v", r.name, r.expectedType, err))
}
// If this is "connection refused" error, it means that most likely apiserver is not responsive.
// It doesn't make sense to re-list all objects because most likely we will be able to restart
// watch where we ended.
// If that's the case wait and resend watch request.
if urlError, ok := err.(*url.Error); ok {
if opError, ok := urlError.Err.(*net.OpError); ok {
if errno, ok := opError.Err.(syscall.Errno); ok && errno == syscall.ECONNREFUSED {
time.Sleep(time.Second)
continue
}
}
}
return nil
}
if err := r.watchHandler(w, &resourceVersion, resyncCh, stopCh); err != nil {
if err != errorResyncRequested && err != errorStopRequested {
glog.Warningf("%s: watch of %v ended with: %v", r.name, r.expectedType, err)
}
return nil
}
}
}
// waitForConnection waits for new connections to listener and handles them in
// the background.
func (pf *PortForwarder) waitForConnection(listener net.Listener, port ForwardedPort) {
for {
conn, err := listener.Accept()
if err != nil {
// TODO consider using something like https://github.com/hydrogen18/stoppableListener?
if !strings.Contains(strings.ToLower(err.Error()), "use of closed network connection") {
util.HandleError(fmt.Errorf("Error accepting connection on port %d: %v", port.Local, err))
}
return
}
go pf.handleConnection(conn, port)
}
}
// getListener creates a listener on the interface targeted by the given hostname on the given port with
// the given protocol. protocol is in net.Listen style which basically admits values like tcp, tcp4, tcp6
func (pf *PortForwarder) getListener(protocol string, hostname string, port *ForwardedPort) (net.Listener, error) {
listener, err := net.Listen(protocol, fmt.Sprintf("%s:%d", hostname, port.Local))
if err != nil {
util.HandleError(fmt.Errorf("Unable to create listener: Error %s", err))
return nil, err
}
listenerAddress := listener.Addr().String()
host, localPort, _ := net.SplitHostPort(listenerAddress)
localPortUInt, err := strconv.ParseUint(localPort, 10, 16)
if err != nil {
return nil, fmt.Errorf("Error parsing local port: %s from %s (%s)", err, listenerAddress, host)
}
port.Local = uint16(localPortUInt)
glog.Infof("Forwarding from %s:%d -> %d", hostname, localPortUInt, port.Remote)
return listener, nil
}
// handleConnection copies data between the local connection and the stream to
// the remote server.
func (pf *PortForwarder) handleConnection(conn net.Conn, port ForwardedPort) {
defer conn.Close()
glog.Infof("Handling connection for %d", port.Local)
requestID := pf.nextRequestID()
// create error stream
headers := http.Header{}
headers.Set(api.StreamType, api.StreamTypeError)
headers.Set(api.PortHeader, fmt.Sprintf("%d", port.Remote))
headers.Set(api.PortForwardRequestIDHeader, strconv.Itoa(requestID))
errorStream, err := pf.streamConn.CreateStream(headers)
if err != nil {
util.HandleError(fmt.Errorf("error creating error stream for port %d -> %d: %v", port.Local, port.Remote, err))
return
}
// we're not writing to this stream
errorStream.Close()
errorChan := make(chan error)
go func() {
message, err := ioutil.ReadAll(errorStream)
switch {
case err != nil:
errorChan <- fmt.Errorf("error reading from error stream for port %d -> %d: %v", port.Local, port.Remote, err)
case len(message) > 0:
errorChan <- fmt.Errorf("an error occurred forwarding %d -> %d: %v", port.Local, port.Remote, string(message))
}
close(errorChan)
}()
// create data stream
headers.Set(api.StreamType, api.StreamTypeData)
dataStream, err := pf.streamConn.CreateStream(headers)
if err != nil {
util.HandleError(fmt.Errorf("error creating forwarding stream for port %d -> %d: %v", port.Local, port.Remote, err))
return
}
localError := make(chan struct{})
remoteDone := make(chan struct{})
go func() {
// Copy from the remote side to the local port.
if _, err := io.Copy(conn, dataStream); err != nil && !strings.Contains(err.Error(), "use of closed network connection") {
util.HandleError(fmt.Errorf("error copying from remote stream to local connection: %v", err))
}
// inform the select below that the remote copy is done
close(remoteDone)
}()
go func() {
// inform server we're not sending any more data after copy unblocks
defer dataStream.Close()
// Copy from the local port to the remote side.
if _, err := io.Copy(dataStream, conn); err != nil && !strings.Contains(err.Error(), "use of closed network connection") {
util.HandleError(fmt.Errorf("error copying from local connection to remote stream: %v", err))
// break out of the select below without waiting for the other copy to finish
close(localError)
}
}()
// wait for either a local->remote error or for copying from remote->local to finish
select {
case <-remoteDone:
case <-localError:
}
// always expect something on errorChan (it may be nil)
err = <-errorChan
if err != nil {
util.HandleError(err)
}
}
func (e *Streamer) doStream() error {
if e.upgrader == nil {
e.upgrader = &defaultUpgrader{}
}
conn, err := e.upgrader.upgrade(e.req, e.config)
if err != nil {
return err
}
defer conn.Close()
headers := http.Header{}
// set up error stream
errorChan := make(chan error)
headers.Set(api.StreamType, api.StreamTypeError)
errorStream, err := conn.CreateStream(headers)
if err != nil {
return err
}
go func() {
message, err := ioutil.ReadAll(errorStream)
switch {
case err != nil && err != io.EOF:
errorChan <- fmt.Errorf("error reading from error stream: %s", err)
case len(message) > 0:
errorChan <- fmt.Errorf("error executing remote command: %s", message)
default:
errorChan <- nil
}
close(errorChan)
}()
var wg sync.WaitGroup
var once sync.Once
// set up stdin stream
if e.stdin != nil {
headers.Set(api.StreamType, api.StreamTypeStdin)
remoteStdin, err := conn.CreateStream(headers)
if err != nil {
return err
}
// copy from client's stdin to container's stdin
go func() {
// if e.stdin is noninteractive, e.g. `echo abc | kubectl exec -i <pod> -- cat`, make sure
// we close remoteStdin as soon as the copy from e.stdin to remoteStdin finishes. Otherwise
// the executed command will remain running.
defer once.Do(func() { remoteStdin.Close() })
if _, err := io.Copy(remoteStdin, e.stdin); err != nil {
util.HandleError(err)
}
}()
// read from remoteStdin until the stream is closed. this is essential to
// be able to exit interactive sessions cleanly and not leak goroutines or
// hang the client's terminal.
//
// go-dockerclient's current hijack implementation
// (https://github.com/fsouza/go-dockerclient/blob/89f3d56d93788dfe85f864a44f85d9738fca0670/client.go#L564)
// waits for all three streams (stdin/stdout/stderr) to finish copying
// before returning. When hijack finishes copying stdout/stderr, it calls
// Close() on its side of remoteStdin, which allows this copy to complete.
// When that happens, we must Close() on our side of remoteStdin, to
// allow the copy in hijack to complete, and hijack to return.
go func() {
defer once.Do(func() { remoteStdin.Close() })
// this "copy" doesn't actually read anything - it's just here to wait for
// the server to close remoteStdin.
if _, err := io.Copy(ioutil.Discard, remoteStdin); err != nil {
util.HandleError(err)
}
}()
}
// set up stdout stream
if e.stdout != nil {
headers.Set(api.StreamType, api.StreamTypeStdout)
remoteStdout, err := conn.CreateStream(headers)
if err != nil {
return err
}
wg.Add(1)
go func() {
defer wg.Done()
if _, err := io.Copy(e.stdout, remoteStdout); err != nil {
util.HandleError(err)
}
}()
}
// set up stderr stream
if e.stderr != nil && !e.tty {
headers.Set(api.StreamType, api.StreamTypeStderr)
remoteStderr, err := conn.CreateStream(headers)
if err != nil {
return err
}
wg.Add(1)
go func() {
defer wg.Done()
if _, err := io.Copy(e.stderr, remoteStderr); err != nil {
util.HandleError(err)
}
}()
}
// we're waiting for stdout/stderr to finish copying
wg.Wait()
// waits for errorStream to finish reading with an error or nil
return <-errorChan
}
