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@tr4cks
tr4cks committed Mar 11, 2021
1 parent ad745e4 commit 5ff3fa2
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Showing 6 changed files with 220 additions and 111 deletions.
152 changes: 136 additions & 16 deletions cmd/root.go
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Original file line number Diff line number Diff line change
@@ -1,26 +1,42 @@
package cmd

import (
"bytes"
"context"
yamlConfig "docker-netns/config"
"fmt"
"github.com/docker/docker/api/types"
"github.com/docker/docker/api/types/filters"
"github.com/docker/docker/client"
"github.com/kardianos/service"
"github.com/kballard/go-shellquote"
"github.com/spf13/cobra"
"github.com/vishvananda/netns"
"log"
"os"
"os/exec"
"path"
"runtime"
"syscall"
)

func init() {
rootCmd.Flags().StringVar(&configPath, "config", path.Join("/opt", appName, "config.yaml"), "YAML configuration file")
}

const appName = "docker-netns"

var (
logger service.Logger
rootCmd = &cobra.Command{
Use: "docker-netns",
Short: "Docker network namespace manager",
configPath string
logger service.Logger
rootCmd = &cobra.Command{
Use: appName,
Short: "Docker network namespace manager",
Version: "1.0.0",
Run: func(cmd *cobra.Command, args []string) {
prg := &program{}
prg := NewProgram()
s, err := service.New(prg, svcConfig)
prg.service = s
if err != nil {
fmt.Fprintf(os.Stderr, "[service.New] %v\n", err)
os.Exit(1)
Expand All @@ -33,13 +49,14 @@ var (
err = s.Run()
if err != nil {
logger.Error(err)
os.Exit(1)
}
},
}
svcConfig = &service.Config{
Name: "docker-netns",
Name: "docker-netns",
DisplayName: "Docker network namespace service",
UserName: "root",
UserName: "root",
Dependencies: []string{
"After=network.target syslog.target docker.service",
},
Expand All @@ -49,37 +66,140 @@ var (
}
)

type program struct {}
func nsContext(containerID string, callback func() (interface{}, error)) (interface{}, error) {
runtime.LockOSThread()
defer runtime.UnlockOSThread()
originNamespace, err := netns.Get()
if err != nil {
return nil, err
}
defer originNamespace.Close()
cli, err := client.NewClientWithOpts(client.WithVersion("1.40"))
if err != nil {
return nil, err
}
container, err := cli.ContainerInspect(context.Background(), containerID)
if err != nil {
return nil, err
}
ContainerNamespace, err := netns.GetFromPid(container.State.Pid)
if err != nil {
return nil, err
}
defer ContainerNamespace.Close()
err = netns.Set(ContainerNamespace)
if err != nil {
return nil, err
}
res, err := callback()
if err != nil {
return res, err
}
err = netns.Set(originNamespace)
if err != nil {
return nil, err
}
return res, nil
}

func execCommands(containerID string, commands []string) error {
_, err := nsContext(containerID, func() (interface{}, error) {
for _, command := range commands {
command, err := shellquote.Split(command)
if err != nil {
return nil, err
}
execCmd := exec.Command(command[0], command[1:]...)
var stderr bytes.Buffer
execCmd.Stderr = &stderr
err = execCmd.Run()
if err != nil {
return nil, fmt.Errorf("%v: %v", err, stderr.String())
}
}
return nil, nil
})
return err
}

type program struct {
service service.Service
ctx context.Context
cancel context.CancelFunc
exited chan error
}

func NewProgram() *program {
ctx, cancel := context.WithCancel(context.Background())
exited := make(chan error)
return &program{ctx: ctx, cancel: cancel, exited: exited}
}

func (p *program) Start(s service.Service) error {
// Start should not block. Do the actual work async.
config, err := yamlConfig.NewConfig(configPath)
if err != nil {
return err
}
cli, err := client.NewClientWithOpts(client.WithVersion("1.40"))
if err != nil {
return err
}
go p.run(cli)
go p.run(config, cli)
return nil
}

func (p *program) run(cli *client.Client) {
ctx := context.Background()
func (p *program) run(config *yamlConfig.Config, cli *client.Client) {
defer close(p.exited)
process, _ := os.FindProcess(os.Getpid())
containers, err := cli.ContainerList(context.Background(), types.ContainerListOptions{})
if err != nil {
process.Signal(syscall.SIGTERM)
p.exited <- err
return
}
for containerID := range *config {
for _, container := range containers {
if containerID == container.ID[:len(containerID)] {
err := execCommands(containerID, (*config)[containerID])
if err != nil {
process.Signal(syscall.SIGTERM)
p.exited <- err
return
}
break
}
}
}

f := filters.NewArgs()
f.Add("event", "start")
msgs, errs := cli.Events(ctx, types.EventsOptions{Filters: f})
msgs, errs := cli.Events(p.ctx, types.EventsOptions{Filters: f})
for {
select {
case msg := <-msgs:
_ = msg
case <-p.ctx.Done():
return
case <-msgs:
for containerID := range *config {
err := execCommands(containerID, (*config)[containerID])
if err != nil {
process.Signal(syscall.SIGTERM)
p.exited <- err
return
}
}
case err := <-errs:
_ = err
process.Signal(syscall.SIGTERM)
p.exited <- err
return
}
}
}

func (p *program) Stop(s service.Service) error {
// Stop should not block. Return with a few seconds.
return nil
p.cancel()
return <-p.exited
}

func Execute() {
Expand Down
78 changes: 68 additions & 10 deletions cmd/service.go
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Original file line number Diff line number Diff line change
Expand Up @@ -4,30 +4,88 @@ import (
"fmt"
"github.com/kardianos/service"
"github.com/spf13/cobra"
"io/ioutil"
"os"
"strings"
"path"
)

func init() {
serviceCmd.Flags().StringP("action", "a", "", strings.Join(service.ControlAction[:], "|"))
serviceCmd.MarkFlagRequired("action")
installCmd.Flags().String("config", "./config.yaml", "YAML configuration file")
serviceCmd.AddCommand(startCmd, stopCmd, restartCmd, installCmd, uninstallCmd)
rootCmd.AddCommand(serviceCmd)
}

var serviceCmd = &cobra.Command{
Use: "service",
Short: "Service management",
Run: func(cmd *cobra.Command, args []string) {
prg := &program{}
func serviceControl(action string) func(*cobra.Command, []string) {
return func(cmd *cobra.Command, args []string) {
prg := NewProgram()
s, err := service.New(prg, svcConfig)
prg.service = s
if err != nil {
fmt.Fprintf(os.Stderr, "[service.New] %v\n", err)
os.Exit(1)
}
err = service.Control(s, cmd.Flag("action").Value.String())
err = service.Control(s, action)
if err != nil {
fmt.Fprintf(os.Stderr, "[service.Control] %v\n", err)
os.Exit(1)
}
},
}
}

var (
serviceCmd = &cobra.Command{
Use: "service",
Short: "Service management",
}
startCmd = &cobra.Command{
Use: "start",
Short: "Start service",
Run: serviceControl("start"),
}
stopCmd = &cobra.Command{
Use: "stop",
Short: "Stop service",
Run: serviceControl("stop"),
}
restartCmd = &cobra.Command{
Use: "restart",
Short: "Restart service",
Run: serviceControl("restart"),
}
installCmd = &cobra.Command{
Use: "install",
Short: "Install service",
Run: func(cmd *cobra.Command, args []string) {
// TODO: transaction
err := os.Mkdir(path.Join("/opt", appName), 0755)
if err != nil {
fmt.Fprintf(os.Stderr, "[os.Mkdir] %v\n", err)
os.Exit(1)
}
bytes, err := ioutil.ReadFile(cmd.Flag("config").Value.String())
if err != nil {
fmt.Fprintf(os.Stderr, "[ioutil.ReadFile] %v\n", err)
os.Exit(1)
}
err = ioutil.WriteFile(path.Join("/opt", appName, "config.yaml"), bytes, 0644)
if err != nil {
fmt.Fprintf(os.Stderr, "[ioutil.WriteFile] %v\n", err)
os.Exit(1)
}
serviceControl("install")(cmd, args)
},
}
uninstallCmd = &cobra.Command{
Use: "uninstall",
Short: "Uninstall service",
Run: func(cmd *cobra.Command, args []string) {
// TODO: transaction
err := os.RemoveAll(path.Join("/opt", appName))
if err != nil {
fmt.Fprintf(os.Stderr, "[ioutil.RemoveAll] %v\n", err)
os.Exit(1)
}
serviceControl("uninstall")(cmd, args)
},
}
)
55 changes: 11 additions & 44 deletions cmd/shell.go
View file
Original file line number Diff line number Diff line change
@@ -1,14 +1,10 @@
package cmd

import (
"context"
"fmt"
"github.com/docker/docker/client"
"github.com/spf13/cobra"
"github.com/vishvananda/netns"
"os"
"os/exec"
"runtime"
)

func init() {
Expand All @@ -21,49 +17,20 @@ var shellCmd = &cobra.Command{
Use: "shell",
Short: "Start a shell in a specific network namespace",
Run: func(cmd *cobra.Command, args []string) {
runtime.LockOSThread()
defer runtime.UnlockOSThread()
originNamespace, err := netns.Get()
if err != nil {
fmt.Fprintf(os.Stderr, "[netns.Get] %v\n", err)
os.Exit(1)
}
defer originNamespace.Close()
cli, err := client.NewClientWithOpts(client.WithVersion("1.40"))
if err != nil {
fmt.Fprintf(os.Stderr, "[client.NewClientWithOpts] %v\n", err)
os.Exit(1)
}
container, err := cli.ContainerInspect(context.Background(), cmd.Flag("container").Value.String())
if err != nil {
fmt.Fprintf(os.Stderr, "[cli.ContainerInspect] %v\n", err)
os.Exit(1)
}
println(container.State.Pid)
ContainerNamespace, err := netns.GetFromPid(container.State.Pid)
if err != nil {
fmt.Fprintf(os.Stderr, "[netns.GetFromPid] %v\n", err)
os.Exit(1)
}
defer ContainerNamespace.Close()
err = netns.Set(ContainerNamespace)
if err != nil {
fmt.Fprintf(os.Stderr, "[netns.Set] %v\n", err)
os.Exit(1)
}
shell := exec.Command(os.Getenv("SHELL"))
shell.Stdin = os.Stdin
shell.Stdout = os.Stdout
shell.Stderr = os.Stderr
err = shell.Run()
_, err := nsContext(cmd.Flag("container").Value.String(), func() (interface{}, error) {
shell := exec.Command(os.Getenv("SHELL"))
shell.Stdin = os.Stdin
shell.Stdout = os.Stdout
shell.Stderr = os.Stderr
err := shell.Run()
if err != nil {
return nil, err
}
return nil, nil
})
if err != nil {
fmt.Fprintf(os.Stderr, "[shell.Run] %v\n", err)
os.Exit(1)
}
err = netns.Set(originNamespace)
if err != nil {
fmt.Fprintf(os.Stderr, "[netns.Set] %v\n", err)
os.Exit(1)
}
},
}
5 changes: 2 additions & 3 deletions config.yaml
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Original file line number Diff line number Diff line change
@@ -1,3 +1,2 @@
d8b71122deaa:
- ip route add default via 192.168.1.254 dev eth0

360f9c13f2ab9:
- iptables -P OUTPUT DROP
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