416a3ba62e
Reusing k8s existing implementation. This could be re-written to do port-forwarding natively rather than relying on socat/nsenter. Signed-off-by: Mrunal Patel <mrunalp@gmail.com>
86 lines
2.7 KiB
Go
86 lines
2.7 KiB
Go
package server
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import (
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"bytes"
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"fmt"
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"io"
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"os/exec"
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"strings"
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"github.com/Sirupsen/logrus"
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"github.com/kubernetes-incubator/cri-o/oci"
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"golang.org/x/net/context"
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pb "k8s.io/kubernetes/pkg/kubelet/api/v1alpha1/runtime"
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)
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// PortForward prepares a streaming endpoint to forward ports from a PodSandbox.
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func (s *Server) PortForward(ctx context.Context, req *pb.PortForwardRequest) (*pb.PortForwardResponse, error) {
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logrus.Debugf("PortForwardRequest %+v", req)
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resp, err := s.GetPortForward(req)
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if err != nil {
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return nil, fmt.Errorf("unable to prepare portforward endpoint")
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}
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return resp, nil
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}
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func (ss streamService) PortForward(podInfraContainerID string, port int32, stream io.ReadWriteCloser) error {
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c := ss.runtimeServer.state.containers.Get(podInfraContainerID)
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if err := ss.runtimeServer.runtime.UpdateStatus(c); err != nil {
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return err
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}
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cState := ss.runtimeServer.runtime.ContainerStatus(c)
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if !(cState.Status == oci.ContainerStateRunning || cState.Status == oci.ContainerStateCreated) {
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return fmt.Errorf("container is not created or running")
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}
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containerPid := cState.Pid
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socatPath, lookupErr := exec.LookPath("socat")
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if lookupErr != nil {
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return fmt.Errorf("unable to do port forwarding: socat not found")
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}
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args := []string{"-t", fmt.Sprintf("%d", containerPid), "-n", socatPath, "-", fmt.Sprintf("TCP4:localhost:%d", port)}
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nsenterPath, lookupErr := exec.LookPath("nsenter")
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if lookupErr != nil {
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return fmt.Errorf("unable to do port forwarding: nsenter not found")
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}
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commandString := fmt.Sprintf("%s %s", nsenterPath, strings.Join(args, " "))
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logrus.Debugf("executing port forwarding command: %s", commandString)
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command := exec.Command(nsenterPath, args...)
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command.Stdout = stream
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stderr := new(bytes.Buffer)
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command.Stderr = stderr
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// If we use Stdin, command.Run() won't return until the goroutine that's copying
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// from stream finishes. Unfortunately, if you have a client like telnet connected
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// via port forwarding, as long as the user's telnet client is connected to the user's
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// local listener that port forwarding sets up, the telnet session never exits. This
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// means that even if socat has finished running, command.Run() won't ever return
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// (because the client still has the connection and stream open).
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//
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// The work around is to use StdinPipe(), as Wait() (called by Run()) closes the pipe
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// when the command (socat) exits.
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inPipe, err := command.StdinPipe()
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if err != nil {
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return fmt.Errorf("unable to do port forwarding: error creating stdin pipe: %v", err)
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}
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go func() {
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io.Copy(inPipe, stream)
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inPipe.Close()
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}()
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if err := command.Run(); err != nil {
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return fmt.Errorf("%v: %s", err, stderr.String())
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}
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return nil
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}
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