package docker import ( "encoding/json" "fmt" "github.com/dotcloud/docker/rcli" "github.com/kr/pty" "io" "io/ioutil" "log" "os" "os/exec" "path" "strconv" "syscall" "time" ) type Container struct { root string Id string Created time.Time Path string Args []string Config *Config State State Image string network *NetworkInterface NetworkSettings *NetworkSettings SysInitPath string cmd *exec.Cmd stdout *writeBroadcaster stderr *writeBroadcaster stdin io.ReadCloser stdinPipe io.WriteCloser ptyStdinMaster io.Closer ptyStdoutMaster io.Closer ptyStderrMaster io.Closer runtime *Runtime } type Config struct { Hostname string User string Memory int64 // Memory limit (in bytes) MemorySwap int64 // Total memory usage (memory + swap); set `-1' to disable swap AttachStdin bool AttachStdout bool AttachStderr bool Ports []int Tty bool // Attach standard streams to a tty, including stdin if it is not closed. OpenStdin bool // Open stdin StdinOnce bool // If true, close stdin after the 1 attached client disconnects. Env []string Cmd []string Image string // Name of the image as it was passed by the operator (eg. could be symbolic) } func ParseRun(args []string, stdout io.Writer) (*Config, error) { cmd := rcli.Subcmd(stdout, "run", "[OPTIONS] IMAGE COMMAND [ARG...]", "Run a command in a new container") if len(args) > 0 && args[0] != "--help" { cmd.SetOutput(ioutil.Discard) } flHostname := cmd.String("h", "", "Container host name") flUser := cmd.String("u", "", "Username or UID") flDetach := cmd.Bool("d", false, "Detached mode: leave the container running in the background") flAttach := NewAttachOpts() cmd.Var(flAttach, "a", "Attach to stdin, stdout or stderr.") flStdin := cmd.Bool("i", false, "Keep stdin open even if not attached") flTty := cmd.Bool("t", false, "Allocate a pseudo-tty") flMemory := cmd.Int64("m", 0, "Memory limit (in bytes)") var flPorts ports cmd.Var(&flPorts, "p", "Map a network port to the container") var flEnv ListOpts cmd.Var(&flEnv, "e", "Set environment variables") if err := cmd.Parse(args); err != nil { return nil, err } if *flDetach && len(*flAttach) > 0 { return nil, fmt.Errorf("Conflicting options: -a and -d") } // If neither -d or -a are set, attach to everything by default if len(*flAttach) == 0 && !*flDetach { if !*flDetach { flAttach.Set("stdout") flAttach.Set("stderr") if *flStdin { flAttach.Set("stdin") } } } parsedArgs := cmd.Args() runCmd := []string{} image := "" if len(parsedArgs) >= 1 { image = cmd.Arg(0) } if len(parsedArgs) > 1 { runCmd = parsedArgs[1:] } config := &Config{ Hostname: *flHostname, Ports: flPorts, User: *flUser, Tty: *flTty, OpenStdin: *flStdin, Memory: *flMemory, AttachStdin: flAttach.Get("stdin"), AttachStdout: flAttach.Get("stdout"), AttachStderr: flAttach.Get("stderr"), Env: flEnv, Cmd: runCmd, Image: image, } // When allocating stdin in attached mode, close stdin at client disconnect if config.OpenStdin && config.AttachStdin { config.StdinOnce = true } return config, nil } type NetworkSettings struct { IpAddress string IpPrefixLen int Gateway string PortMapping map[string]string } func (container *Container) Cmd() *exec.Cmd { return container.cmd } func (container *Container) When() time.Time { return container.Created } func (container *Container) FromDisk() error { data, err := ioutil.ReadFile(container.jsonPath()) if err != nil { return err } // Load container settings if err := json.Unmarshal(data, container); err != nil { return err } return nil } func (container *Container) ToDisk() (err error) { data, err := json.Marshal(container) if err != nil { return } return ioutil.WriteFile(container.jsonPath(), data, 0666) } func (container *Container) generateLXCConfig() error { fo, err := os.Create(container.lxcConfigPath()) if err != nil { return err } defer fo.Close() if err := LxcTemplateCompiled.Execute(fo, container); err != nil { return err } return nil } func (container *Container) startPty() error { stdoutMaster, stdoutSlave, err := pty.Open() if err != nil { return err } container.ptyStdoutMaster = stdoutMaster container.cmd.Stdout = stdoutSlave stderrMaster, stderrSlave, err := pty.Open() if err != nil { return err } container.ptyStderrMaster = stderrMaster container.cmd.Stderr = stderrSlave // Copy the PTYs to our broadcasters go func() { defer container.stdout.CloseWriters() Debugf("[startPty] Begin of stdout pipe") io.Copy(container.stdout, stdoutMaster) Debugf("[startPty] End of stdout pipe") }() go func() { defer container.stderr.CloseWriters() Debugf("[startPty] Begin of stderr pipe") io.Copy(container.stderr, stderrMaster) Debugf("[startPty] End of stderr pipe") }() // stdin var stdinSlave io.ReadCloser if container.Config.OpenStdin { var stdinMaster io.WriteCloser stdinMaster, stdinSlave, err = pty.Open() if err != nil { return err } container.ptyStdinMaster = stdinMaster container.cmd.Stdin = stdinSlave // FIXME: The following appears to be broken. // "cannot set terminal process group (-1): Inappropriate ioctl for device" // container.cmd.SysProcAttr = &syscall.SysProcAttr{Setctty: true, Setsid: true} go func() { defer container.stdin.Close() Debugf("[startPty] Begin of stdin pipe") io.Copy(stdinMaster, container.stdin) Debugf("[startPty] End of stdin pipe") }() } if err := container.cmd.Start(); err != nil { return err } stdoutSlave.Close() stderrSlave.Close() if stdinSlave != nil { stdinSlave.Close() } return nil } func (container *Container) start() error { container.cmd.Stdout = container.stdout container.cmd.Stderr = container.stderr if container.Config.OpenStdin { stdin, err := container.cmd.StdinPipe() if err != nil { return err } go func() { defer stdin.Close() Debugf("Begin of stdin pipe [start]") io.Copy(stdin, container.stdin) Debugf("End of stdin pipe [start]") }() } return container.cmd.Start() } func (container *Container) Attach(stdin io.Reader, stdout io.Writer, stderr io.Writer) chan error { var cStdout io.ReadCloser var cStderr io.ReadCloser var nJobs int errors := make(chan error, 3) if stdin != nil && container.Config.OpenStdin { nJobs += 1 if cStdin, err := container.StdinPipe(); err != nil { errors <- err } else { go func() { Debugf("[start] attach stdin\n") defer Debugf("[end] attach stdin\n") if container.Config.StdinOnce { defer cStdin.Close() } _, err := io.Copy(cStdin, stdin) if err != nil { Debugf("[error] attach stdout: %s\n", err) } errors <- err }() } } if stdout != nil { nJobs += 1 if p, err := container.StdoutPipe(); err != nil { errors <- err } else { cStdout = p go func() { Debugf("[start] attach stdout\n") defer Debugf("[end] attach stdout\n") _, err := io.Copy(stdout, cStdout) if err != nil { Debugf("[error] attach stdout: %s\n", err) } errors <- err }() } } if stderr != nil { nJobs += 1 if p, err := container.StderrPipe(); err != nil { errors <- err } else { cStderr = p go func() { Debugf("[start] attach stderr\n") defer Debugf("[end] attach stderr\n") _, err := io.Copy(stderr, cStderr) if err != nil { Debugf("[error] attach stderr: %s\n", err) } errors <- err }() } } return Go(func() error { if cStdout != nil { defer cStdout.Close() } if cStderr != nil { defer cStderr.Close() } // FIXME: how do clean up the stdin goroutine without the unwanted side effect // of closing the passed stdin? Add an intermediary io.Pipe? for i := 0; i < nJobs; i += 1 { Debugf("Waiting for job %d/%d\n", i+1, nJobs) if err := <-errors; err != nil { Debugf("Job %d returned error %s. Aborting all jobs\n", i+1, err) return err } Debugf("Job %d completed successfully\n", i+1) } Debugf("All jobs completed successfully\n") return nil }) } func (container *Container) Start() error { if container.State.Running { return fmt.Errorf("The container %s is already running.", container.Id) } if err := container.EnsureMounted(); err != nil { return err } if err := container.allocateNetwork(); err != nil { return err } if err := container.generateLXCConfig(); err != nil { return err } params := []string{ "-n", container.Id, "-f", container.lxcConfigPath(), "--", "/sbin/init", } // Networking params = append(params, "-g", container.network.Gateway.String()) // User if container.Config.User != "" { params = append(params, "-u", container.Config.User) } // Program params = append(params, "--", container.Path) params = append(params, container.Args...) container.cmd = exec.Command("lxc-start", params...) // Setup environment container.cmd.Env = append( []string{ "HOME=/", "PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin", }, container.Config.Env..., ) // Setup logging of stdout and stderr to disk if err := container.runtime.LogToDisk(container.stdout, container.logPath("stdout")); err != nil { return err } if err := container.runtime.LogToDisk(container.stderr, container.logPath("stderr")); err != nil { return err } var err error if container.Config.Tty { container.cmd.Env = append( []string{"TERM=xterm"}, container.cmd.Env..., ) err = container.startPty() } else { err = container.start() } if err != nil { return err } // FIXME: save state on disk *first*, then converge // this way disk state is used as a journal, eg. we can restore after crash etc. container.State.setRunning(container.cmd.Process.Pid) container.ToDisk() go container.monitor() return nil } func (container *Container) Run() error { if err := container.Start(); err != nil { return err } container.Wait() return nil } func (container *Container) Output() (output []byte, err error) { pipe, err := container.StdoutPipe() if err != nil { return nil, err } defer pipe.Close() if err := container.Start(); err != nil { return nil, err } output, err = ioutil.ReadAll(pipe) container.Wait() return output, err } // StdinPipe() returns a pipe connected to the standard input of the container's // active process. // func (container *Container) StdinPipe() (io.WriteCloser, error) { return container.stdinPipe, nil } func (container *Container) StdoutPipe() (io.ReadCloser, error) { reader, writer := io.Pipe() container.stdout.AddWriter(writer) return newBufReader(reader), nil } func (container *Container) StderrPipe() (io.ReadCloser, error) { reader, writer := io.Pipe() container.stderr.AddWriter(writer) return newBufReader(reader), nil } func (container *Container) allocateNetwork() error { iface, err := container.runtime.networkManager.Allocate() if err != nil { return err } container.NetworkSettings.PortMapping = make(map[string]string) for _, port := range container.Config.Ports { if extPort, err := iface.AllocatePort(port); err != nil { iface.Release() return err } else { container.NetworkSettings.PortMapping[strconv.Itoa(port)] = strconv.Itoa(extPort) } } container.network = iface container.NetworkSettings.IpAddress = iface.IPNet.IP.String() container.NetworkSettings.IpPrefixLen, _ = iface.IPNet.Mask.Size() container.NetworkSettings.Gateway = iface.Gateway.String() return nil } func (container *Container) releaseNetwork() { container.network.Release() container.network = nil container.NetworkSettings = &NetworkSettings{} } func (container *Container) monitor() { // Wait for the program to exit Debugf("Waiting for process") if err := container.cmd.Wait(); err != nil { // Discard the error as any signals or non 0 returns will generate an error Debugf("%s: Process: %s", container.Id, err) } Debugf("Process finished") exitCode := container.cmd.ProcessState.Sys().(syscall.WaitStatus).ExitStatus() // Cleanup container.releaseNetwork() if container.Config.OpenStdin { if err := container.stdin.Close(); err != nil { Debugf("%s: Error close stdin: %s", container.Id, err) } } if err := container.stdout.CloseWriters(); err != nil { Debugf("%s: Error close stdout: %s", container.Id, err) } if err := container.stderr.CloseWriters(); err != nil { Debugf("%s: Error close stderr: %s", container.Id, err) } if container.ptyStdinMaster != nil { if err := container.ptyStdinMaster.Close(); err != nil { Debugf("%s: Error close pty stdin master: %s", container.Id, err) } } if container.ptyStdoutMaster != nil { if err := container.ptyStdoutMaster.Close(); err != nil { Debugf("%s: Error close pty stdout master: %s", container.Id, err) } } if container.ptyStderrMaster != nil { if err := container.ptyStderrMaster.Close(); err != nil { Debugf("%s: Error close pty stderr master: %s", container.Id, err) } } if err := container.Unmount(); err != nil { log.Printf("%v: Failed to umount filesystem: %v", container.Id, err) } // Re-create a brand new stdin pipe once the container exited if container.Config.OpenStdin { container.stdin, container.stdinPipe = io.Pipe() } // Report status back container.State.setStopped(exitCode) if err := container.ToDisk(); err != nil { // FIXME: there is a race condition here which causes this to fail during the unit tests. // If another goroutine was waiting for Wait() to return before removing the container's root // from the filesystem... At this point it may already have done so. // This is because State.setStopped() has already been called, and has caused Wait() // to return. // FIXME: why are we serializing running state to disk in the first place? //log.Printf("%s: Failed to dump configuration to the disk: %s", container.Id, err) } } func (container *Container) kill() error { if container.cmd == nil { return nil } if err := container.cmd.Process.Kill(); err != nil { return err } // Wait for the container to be actually stopped container.Wait() return nil } func (container *Container) Kill() error { if !container.State.Running { return nil } return container.kill() } func (container *Container) Stop() error { if !container.State.Running { return nil } // 1. Send a SIGTERM if output, err := exec.Command("lxc-kill", "-n", container.Id, "15").CombinedOutput(); err != nil { log.Print(string(output)) log.Print("Failed to send SIGTERM to the process, force killing") if err := container.Kill(); err != nil { return err } } // 2. Wait for the process to exit on its own if err := container.WaitTimeout(10 * time.Second); err != nil { log.Printf("Container %v failed to exit within 10 seconds of SIGTERM - using the force", container.Id) if err := container.Kill(); err != nil { return err } } return nil } func (container *Container) Restart() error { if err := container.Stop(); err != nil { return err } if err := container.Start(); err != nil { return err } return nil } // Wait blocks until the container stops running, then returns its exit code. func (container *Container) Wait() int { for container.State.Running { container.State.wait() } return container.State.ExitCode } func (container *Container) ExportRw() (Archive, error) { return Tar(container.rwPath(), Uncompressed) } func (container *Container) Export() (Archive, error) { if err := container.EnsureMounted(); err != nil { return nil, err } return Tar(container.RootfsPath(), Uncompressed) } func (container *Container) WaitTimeout(timeout time.Duration) error { done := make(chan bool) go func() { container.Wait() done <- true }() select { case <-time.After(timeout): return fmt.Errorf("Timed Out") case <-done: return nil } return nil } func (container *Container) EnsureMounted() error { if mounted, err := container.Mounted(); err != nil { return err } else if mounted { return nil } return container.Mount() } func (container *Container) Mount() error { image, err := container.GetImage() if err != nil { return err } return image.Mount(container.RootfsPath(), container.rwPath()) } func (container *Container) Changes() ([]Change, error) { image, err := container.GetImage() if err != nil { return nil, err } return image.Changes(container.rwPath()) } func (container *Container) GetImage() (*Image, error) { if container.runtime == nil { return nil, fmt.Errorf("Can't get image of unregistered container") } return container.runtime.graph.Get(container.Image) } func (container *Container) Mounted() (bool, error) { return Mounted(container.RootfsPath()) } func (container *Container) Unmount() error { return Unmount(container.RootfsPath()) } // ShortId returns a shorthand version of the container's id for convenience. // A collision with other container shorthands is very unlikely, but possible. // In case of a collision a lookup with Runtime.Get() will fail, and the caller // will need to use a langer prefix, or the full-length container Id. func (container *Container) ShortId() string { return TruncateId(container.Id) } func (container *Container) logPath(name string) string { return path.Join(container.root, fmt.Sprintf("%s-%s.log", container.Id, name)) } func (container *Container) ReadLog(name string) (io.Reader, error) { return os.Open(container.logPath(name)) } func (container *Container) jsonPath() string { return path.Join(container.root, "config.json") } func (container *Container) lxcConfigPath() string { return path.Join(container.root, "config.lxc") } // This method must be exported to be used from the lxc template func (container *Container) RootfsPath() string { return path.Join(container.root, "rootfs") } func (container *Container) rwPath() string { return path.Join(container.root, "rw") } func validateId(id string) error { if id == "" { return fmt.Errorf("Invalid empty id") } return nil }