cri-o/server/container_portforward.go
Antonio Murdaca b211061016
copy using bytes pools
Vendor and use docker/pkg/pools.
pools are used to lower the number of memory allocations and reuse buffers when
processing large streams operations..

The use of pools.Copy avoids io.Copy's internal buffer allocation.
This commit replaces io.Copy with pools.Copy to avoid the allocation of
buffers in io.Copy.

Signed-off-by: Antonio Murdaca <runcom@redhat.com>
2017-06-12 12:53:23 +02:00

91 lines
2.8 KiB
Go

package server
import (
"bytes"
"fmt"
"io"
"os/exec"
"strings"
"github.com/Sirupsen/logrus"
"github.com/docker/docker/pkg/pools"
"github.com/kubernetes-incubator/cri-o/oci"
"golang.org/x/net/context"
pb "k8s.io/kubernetes/pkg/kubelet/api/v1alpha1/runtime"
)
// PortForward prepares a streaming endpoint to forward ports from a PodSandbox.
func (s *Server) PortForward(ctx context.Context, req *pb.PortForwardRequest) (*pb.PortForwardResponse, error) {
logrus.Debugf("PortForwardRequest %+v", req)
resp, err := s.GetPortForward(req)
if err != nil {
return nil, fmt.Errorf("unable to prepare portforward endpoint")
}
return resp, nil
}
func (ss streamService) PortForward(podSandboxID string, port int32, stream io.ReadWriteCloser) error {
c := ss.runtimeServer.GetSandboxContainer(podSandboxID)
if c == nil {
return fmt.Errorf("could not find container for sandbox %q", podSandboxID)
}
if err := ss.runtimeServer.runtime.UpdateStatus(c); err != nil {
return err
}
cState := ss.runtimeServer.runtime.ContainerStatus(c)
if !(cState.Status == oci.ContainerStateRunning || cState.Status == oci.ContainerStateCreated) {
return fmt.Errorf("container is not created or running")
}
containerPid := cState.Pid
socatPath, lookupErr := exec.LookPath("socat")
if lookupErr != nil {
return fmt.Errorf("unable to do port forwarding: socat not found")
}
args := []string{"-t", fmt.Sprintf("%d", containerPid), "-n", socatPath, "-", fmt.Sprintf("TCP4:localhost:%d", port)}
nsenterPath, lookupErr := exec.LookPath("nsenter")
if lookupErr != nil {
return fmt.Errorf("unable to do port forwarding: nsenter not found")
}
commandString := fmt.Sprintf("%s %s", nsenterPath, strings.Join(args, " "))
logrus.Debugf("executing port forwarding command: %s", commandString)
command := exec.Command(nsenterPath, args...)
command.Stdout = stream
stderr := new(bytes.Buffer)
command.Stderr = stderr
// If we use Stdin, command.Run() won't return until the goroutine that's copying
// from stream finishes. Unfortunately, if you have a client like telnet connected
// via port forwarding, as long as the user's telnet client is connected to the user's
// local listener that port forwarding sets up, the telnet session never exits. This
// means that even if socat has finished running, command.Run() won't ever return
// (because the client still has the connection and stream open).
//
// The work around is to use StdinPipe(), as Wait() (called by Run()) closes the pipe
// when the command (socat) exits.
inPipe, err := command.StdinPipe()
if err != nil {
return fmt.Errorf("unable to do port forwarding: error creating stdin pipe: %v", err)
}
go func() {
pools.Copy(inPipe, stream)
inPipe.Close()
}()
if err := command.Run(); err != nil {
return fmt.Errorf("%v: %s", err, stderr.String())
}
return nil
}