github.com/mirantis/virtlet@v1.5.2-0.20191204181327-1659b8a48e9b/pkg/tools/vnc.go (about)

     1  /*
     2  Copyright 2018 Mirantis
     3  
     4  Licensed under the Apache License, Version 2.0 (the "License");
     5  you may not use this file except in compliance with the License.
     6  You may obtain a copy of the License at
     7  
     8      http://www.apache.org/licenses/LICENSE-2.0
     9  
    10  Unless required by applicable law or agreed to in writing, software
    11  distributed under the License is distributed on an "AS IS" BASIS,
    12  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13  See the License for the specific language governing permissions and
    14  limitations under the License.
    15  */
    16  
    17  package tools
    18  
    19  import (
    20  	"bufio"
    21  	"bytes"
    22  	"errors"
    23  	"fmt"
    24  	"io"
    25  	"os"
    26  	"os/signal"
    27  	"strconv"
    28  	"strings"
    29  	"syscall"
    30  
    31  	"github.com/renstrom/dedent"
    32  	"github.com/spf13/cobra"
    33  )
    34  
    35  const (
    36  	vncProtocolName  = "vnc"
    37  	expectedHost     = "127.0.0.1"
    38  	maxDisplayNumber = 0xffff - 5900
    39  )
    40  
    41  // vncCommand provides access to the VNC console of a VM pod
    42  type vncCommand struct {
    43  	client           KubeClient
    44  	podName          string
    45  	port             uint16
    46  	output           io.Writer
    47  	waitForInterrupt bool
    48  }
    49  
    50  // NewVNCCmd returns a cobra.Command that provides access to the VNC console of a VM pod.
    51  func NewVNCCmd(client KubeClient, output io.Writer, waitForInterrupt bool) *cobra.Command {
    52  	vnc := &vncCommand{client: client, output: output, waitForInterrupt: waitForInterrupt}
    53  	cmd := &cobra.Command{
    54  		Use:   "vnc pod [port]",
    55  		Short: "Provide access to the VNC console of a VM pod",
    56  		Long: dedent.Dedent(`
    57  			This command forwards a local port to the VNC port used by the
    58  			specified VM pod. If no local port number is provided, a random
    59  			available port is picked instead. The port number is displayed
    60  			after the forwarding is set up, after which the commands enters
    61  			an endless loop until it's interrupted with Ctrl-C.
    62                  `),
    63  		RunE: func(cmd *cobra.Command, args []string) error {
    64  			if len(args) < 1 {
    65  				return errors.New("pod name not specified")
    66  			}
    67  			vnc.podName = args[0]
    68  
    69  			switch {
    70  			case len(args) > 2:
    71  				return errors.New("more than 2 options")
    72  			case len(args) == 2:
    73  				// port should be unprivileged and below the high ports
    74  				// range
    75  				port, err := strconv.Atoi(args[1])
    76  				if err != nil || port < 1024 || port > 61000 {
    77  					return errors.New("port parameter must be an integer number in range 1000-61000")
    78  				}
    79  				vnc.port = uint16(port)
    80  			}
    81  			return vnc.Run()
    82  		},
    83  	}
    84  	return cmd
    85  }
    86  
    87  // Run executes the command.
    88  func (v *vncCommand) Run() error {
    89  	vmPodInfo, err := v.client.GetVMPodInfo(v.podName)
    90  	if err != nil {
    91  		return fmt.Errorf("can't get VM pod info for %q: %v", v.podName, err)
    92  	}
    93  
    94  	var buffer bytes.Buffer
    95  	virshOutput := bufio.NewWriter(&buffer)
    96  	exitCode, err := v.client.ExecInContainer(
    97  		vmPodInfo.VirtletPodName, "libvirt", "kube-system",
    98  		nil, virshOutput, os.Stderr,
    99  		[]string{"virsh", "domdisplay", vmPodInfo.LibvirtDomainName()},
   100  	)
   101  	if err != nil {
   102  		return fmt.Errorf("error executing virsh in Virtlet pod %q: %v", vmPodInfo.VirtletPodName, err)
   103  	}
   104  	if exitCode != 0 {
   105  		return fmt.Errorf("virsh returned non-zero exit code %d", exitCode)
   106  	}
   107  
   108  	virshOutput.Flush()
   109  	parts := strings.Split(strings.Trim(buffer.String(), "\n"), ":")
   110  	switch {
   111  	case len(parts) != 3:
   112  		return fmt.Errorf("virsh returned %q, while expected to return a value of a form %q", buffer.String(), "vnc://127.0.0.1:0")
   113  	case parts[0] != vncProtocolName:
   114  		return fmt.Errorf("virsh returned %q as a display protocol instead of expected %q", parts[0], vncProtocolName)
   115  	case parts[1][:2] != "//":
   116  		return fmt.Errorf("virsh returned %q after first ':' instead of expected %q", parts[1][:2], "//")
   117  	case parts[1][2:] != expectedHost:
   118  		return fmt.Errorf("virsh returned %q as a display host instead of expected %q", parts[1], expectedHost)
   119  	}
   120  
   121  	displayNumber, err := strconv.Atoi(parts[2])
   122  	if err != nil || displayNumber < 0 || displayNumber > maxDisplayNumber {
   123  		return fmt.Errorf("virsh returned %q as a display number which is expected to be in range 0..%d", parts[2], maxDisplayNumber)
   124  	}
   125  
   126  	pf := &ForwardedPort{
   127  		RemotePort: 5900 + uint16(displayNumber),
   128  		LocalPort:  v.port,
   129  	}
   130  	stopCh, err := v.client.ForwardPorts(vmPodInfo.VirtletPodName, "kube-system", []*ForwardedPort{pf})
   131  	if err != nil {
   132  		return fmt.Errorf("error forwarding the vnc port: %v", err)
   133  	}
   134  	defer close(stopCh)
   135  
   136  	fmt.Fprintf(v.output, "VNC console for pod %q is available on local port %d\n", v.podName, pf.LocalPort)
   137  	fmt.Fprintf(v.output, "Press ctrl-c or kill the process stop.\n")
   138  
   139  	// if waitForInterrupt is set to false do not wait for interrupt (e.x. in tests).
   140  	if v.waitForInterrupt {
   141  		c := make(chan os.Signal, 2)
   142  		signal.Notify(c, os.Interrupt, syscall.SIGTERM)
   143  
   144  		<-c
   145  	}
   146  
   147  	return nil
   148  }