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container.go
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container.go
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package container
import (
"encoding/json"
"fmt"
"io"
"os"
"path/filepath"
"sync"
"syscall"
"time"
"github.com/Sirupsen/logrus"
"github.com/docker/docker/daemon/exec"
"github.com/docker/docker/daemon/execdriver"
"github.com/docker/docker/daemon/logger"
"github.com/docker/docker/daemon/logger/jsonfilelog"
"github.com/docker/docker/daemon/network"
derr "github.com/docker/docker/errors"
"github.com/docker/docker/image"
"github.com/docker/docker/layer"
"github.com/docker/docker/pkg/promise"
"github.com/docker/docker/pkg/signal"
"github.com/docker/docker/pkg/symlink"
"github.com/docker/docker/pkg/system"
"github.com/docker/docker/runconfig"
"github.com/docker/docker/volume"
containertypes "github.com/docker/engine-api/types/container"
"github.com/docker/go-connections/nat"
"github.com/opencontainers/runc/libcontainer/label"
)
const configFileName = "config.v2.json"
// CommonContainer holds the fields for a container which are
// applicable across all platforms supported by the daemon.
type CommonContainer struct {
*runconfig.StreamConfig
// embed for Container to support states directly.
*State `json:"State"` // Needed for remote api version <= 1.11
Root string `json:"-"` // Path to the "home" of the container, including metadata.
BaseFS string `json:"-"` // Path to the graphdriver mountpoint
RWLayer layer.RWLayer `json:"-"`
ID string
Created time.Time
Path string
Args []string
Config *containertypes.Config
ImageID image.ID `json:"Image"`
NetworkSettings *network.Settings
LogPath string
Name string
Driver string
// MountLabel contains the options for the 'mount' command
MountLabel string
ProcessLabel string
RestartCount int
HasBeenStartedBefore bool
HasBeenManuallyStopped bool // used for unless-stopped restart policy
MountPoints map[string]*volume.MountPoint
HostConfig *containertypes.HostConfig `json:"-"` // do not serialize the host config in the json, otherwise we'll make the container unportable
Command *execdriver.Command `json:"-"`
monitor *containerMonitor
ExecCommands *exec.Store `json:"-"`
// logDriver for closing
LogDriver logger.Logger `json:"-"`
LogCopier *logger.Copier `json:"-"`
}
// NewBaseContainer creates a new container with its
// basic configuration.
func NewBaseContainer(id, root string) *Container {
return &Container{
CommonContainer: CommonContainer{
ID: id,
State: NewState(),
ExecCommands: exec.NewStore(),
Root: root,
MountPoints: make(map[string]*volume.MountPoint),
StreamConfig: runconfig.NewStreamConfig(),
},
}
}
// FromDisk loads the container configuration stored in the host.
func (container *Container) FromDisk() error {
pth, err := container.ConfigPath()
if err != nil {
return err
}
jsonSource, err := os.Open(pth)
if err != nil {
return err
}
defer jsonSource.Close()
dec := json.NewDecoder(jsonSource)
// Load container settings
if err := dec.Decode(container); err != nil {
return err
}
if err := label.ReserveLabel(container.ProcessLabel); err != nil {
return err
}
return container.readHostConfig()
}
// ToDisk saves the container configuration on disk.
func (container *Container) ToDisk() error {
pth, err := container.ConfigPath()
if err != nil {
return err
}
jsonSource, err := os.Create(pth)
if err != nil {
return err
}
defer jsonSource.Close()
enc := json.NewEncoder(jsonSource)
// Save container settings
if err := enc.Encode(container); err != nil {
return err
}
return container.WriteHostConfig()
}
// ToDiskLocking saves the container configuration on disk in a thread safe way.
func (container *Container) ToDiskLocking() error {
container.Lock()
err := container.ToDisk()
container.Unlock()
return err
}
// readHostConfig reads the host configuration from disk for the container.
func (container *Container) readHostConfig() error {
container.HostConfig = &containertypes.HostConfig{}
// If the hostconfig file does not exist, do not read it.
// (We still have to initialize container.HostConfig,
// but that's OK, since we just did that above.)
pth, err := container.HostConfigPath()
if err != nil {
return err
}
f, err := os.Open(pth)
if err != nil {
if os.IsNotExist(err) {
return nil
}
return err
}
defer f.Close()
if err := json.NewDecoder(f).Decode(&container.HostConfig); err != nil {
return err
}
container.InitDNSHostConfig()
return nil
}
// WriteHostConfig saves the host configuration on disk for the container.
func (container *Container) WriteHostConfig() error {
pth, err := container.HostConfigPath()
if err != nil {
return err
}
f, err := os.Create(pth)
if err != nil {
return err
}
defer f.Close()
return json.NewEncoder(f).Encode(&container.HostConfig)
}
// SetupWorkingDirectory sets up the container's working directory as set in container.Config.WorkingDir
func (container *Container) SetupWorkingDirectory() error {
if container.Config.WorkingDir == "" {
return nil
}
container.Config.WorkingDir = filepath.Clean(container.Config.WorkingDir)
pth, err := container.GetResourcePath(container.Config.WorkingDir)
if err != nil {
return err
}
if err := system.MkdirAll(pth, 0755); err != nil {
pthInfo, err2 := os.Stat(pth)
if err2 == nil && pthInfo != nil && !pthInfo.IsDir() {
return derr.ErrorCodeNotADir.WithArgs(container.Config.WorkingDir)
}
return err
}
return nil
}
// GetResourcePath evaluates `path` in the scope of the container's BaseFS, with proper path
// sanitisation. Symlinks are all scoped to the BaseFS of the container, as
// though the container's BaseFS was `/`.
//
// The BaseFS of a container is the host-facing path which is bind-mounted as
// `/` inside the container. This method is essentially used to access a
// particular path inside the container as though you were a process in that
// container.
//
// NOTE: The returned path is *only* safely scoped inside the container's BaseFS
// if no component of the returned path changes (such as a component
// symlinking to a different path) between using this method and using the
// path. See symlink.FollowSymlinkInScope for more details.
func (container *Container) GetResourcePath(path string) (string, error) {
// IMPORTANT - These are paths on the OS where the daemon is running, hence
// any filepath operations must be done in an OS agnostic way.
cleanPath := cleanResourcePath(path)
r, e := symlink.FollowSymlinkInScope(filepath.Join(container.BaseFS, cleanPath), container.BaseFS)
return r, e
}
// GetRootResourcePath evaluates `path` in the scope of the container's root, with proper path
// sanitisation. Symlinks are all scoped to the root of the container, as
// though the container's root was `/`.
//
// The root of a container is the host-facing configuration metadata directory.
// Only use this method to safely access the container's `container.json` or
// other metadata files. If in doubt, use container.GetResourcePath.
//
// NOTE: The returned path is *only* safely scoped inside the container's root
// if no component of the returned path changes (such as a component
// symlinking to a different path) between using this method and using the
// path. See symlink.FollowSymlinkInScope for more details.
func (container *Container) GetRootResourcePath(path string) (string, error) {
// IMPORTANT - These are paths on the OS where the daemon is running, hence
// any filepath operations must be done in an OS agnostic way.
cleanPath := filepath.Join(string(os.PathSeparator), path)
return symlink.FollowSymlinkInScope(filepath.Join(container.Root, cleanPath), container.Root)
}
// ExitOnNext signals to the monitor that it should not restart the container
// after we send the kill signal.
func (container *Container) ExitOnNext() {
container.monitor.ExitOnNext()
}
// Resize changes the TTY of the process running inside the container
// to the given height and width. The container must be running.
func (container *Container) Resize(h, w int) error {
if container.Command.ProcessConfig.Terminal == nil {
return fmt.Errorf("Container %s does not have a terminal ready", container.ID)
}
if err := container.Command.ProcessConfig.Terminal.Resize(h, w); err != nil {
return err
}
return nil
}
// HostConfigPath returns the path to the container's JSON hostconfig
func (container *Container) HostConfigPath() (string, error) {
return container.GetRootResourcePath("hostconfig.json")
}
// ConfigPath returns the path to the container's JSON config
func (container *Container) ConfigPath() (string, error) {
return container.GetRootResourcePath(configFileName)
}
func validateID(id string) error {
if id == "" {
return derr.ErrorCodeEmptyID
}
return nil
}
// Returns true if the container exposes a certain port
func (container *Container) exposes(p nat.Port) bool {
_, exists := container.Config.ExposedPorts[p]
return exists
}
// GetLogConfig returns the log configuration for the container.
func (container *Container) GetLogConfig(defaultConfig containertypes.LogConfig) containertypes.LogConfig {
cfg := container.HostConfig.LogConfig
if cfg.Type != "" || len(cfg.Config) > 0 { // container has log driver configured
if cfg.Type == "" {
cfg.Type = jsonfilelog.Name
}
return cfg
}
// Use daemon's default log config for containers
return defaultConfig
}
// StartLogger starts a new logger driver for the container.
func (container *Container) StartLogger(cfg containertypes.LogConfig) (logger.Logger, error) {
c, err := logger.GetLogDriver(cfg.Type)
if err != nil {
return nil, derr.ErrorCodeLoggingFactory.WithArgs(err)
}
ctx := logger.Context{
Config: cfg.Config,
ContainerID: container.ID,
ContainerName: container.Name,
ContainerEntrypoint: container.Path,
ContainerArgs: container.Args,
ContainerImageID: container.ImageID.String(),
ContainerImageName: container.Config.Image,
ContainerCreated: container.Created,
ContainerEnv: container.Config.Env,
ContainerLabels: container.Config.Labels,
}
// Set logging file for "json-logger"
if cfg.Type == jsonfilelog.Name {
ctx.LogPath, err = container.GetRootResourcePath(fmt.Sprintf("%s-json.log", container.ID))
if err != nil {
return nil, err
}
}
return c(ctx)
}
// GetProcessLabel returns the process label for the container.
func (container *Container) GetProcessLabel() string {
// even if we have a process label return "" if we are running
// in privileged mode
if container.HostConfig.Privileged {
return ""
}
return container.ProcessLabel
}
// GetMountLabel returns the mounting label for the container.
// This label is empty if the container is privileged.
func (container *Container) GetMountLabel() string {
if container.HostConfig.Privileged {
return ""
}
return container.MountLabel
}
// GetExecIDs returns the list of exec commands running on the container.
func (container *Container) GetExecIDs() []string {
return container.ExecCommands.List()
}
// Attach connects to the container's TTY, delegating to standard
// streams or websockets depending on the configuration.
func (container *Container) Attach(stdin io.ReadCloser, stdout io.Writer, stderr io.Writer, keys []byte) chan error {
return AttachStreams(container.StreamConfig, container.Config.OpenStdin, container.Config.StdinOnce, container.Config.Tty, stdin, stdout, stderr, keys)
}
// AttachStreams connects streams to a TTY.
// Used by exec too. Should this move somewhere else?
func AttachStreams(streamConfig *runconfig.StreamConfig, openStdin, stdinOnce, tty bool, stdin io.ReadCloser, stdout io.Writer, stderr io.Writer, keys []byte) chan error {
var (
cStdout, cStderr io.ReadCloser
cStdin io.WriteCloser
wg sync.WaitGroup
errors = make(chan error, 3)
)
if stdin != nil && openStdin {
cStdin = streamConfig.StdinPipe()
wg.Add(1)
}
if stdout != nil {
cStdout = streamConfig.StdoutPipe()
wg.Add(1)
}
if stderr != nil {
cStderr = streamConfig.StderrPipe()
wg.Add(1)
}
// Connect stdin of container to the http conn.
go func() {
if stdin == nil || !openStdin {
return
}
logrus.Debugf("attach: stdin: begin")
defer func() {
if stdinOnce && !tty {
cStdin.Close()
} else {
// No matter what, when stdin is closed (io.Copy unblock), close stdout and stderr
if cStdout != nil {
cStdout.Close()
}
if cStderr != nil {
cStderr.Close()
}
}
wg.Done()
logrus.Debugf("attach: stdin: end")
}()
var err error
if tty {
_, err = copyEscapable(cStdin, stdin, keys)
} else {
_, err = io.Copy(cStdin, stdin)
}
if err == io.ErrClosedPipe {
err = nil
}
if err != nil {
logrus.Errorf("attach: stdin: %s", err)
errors <- err
return
}
}()
attachStream := func(name string, stream io.Writer, streamPipe io.ReadCloser) {
if stream == nil {
return
}
defer func() {
// Make sure stdin gets closed
if stdin != nil {
stdin.Close()
}
streamPipe.Close()
wg.Done()
logrus.Debugf("attach: %s: end", name)
}()
logrus.Debugf("attach: %s: begin", name)
_, err := io.Copy(stream, streamPipe)
if err == io.ErrClosedPipe {
err = nil
}
if err != nil {
logrus.Errorf("attach: %s: %v", name, err)
errors <- err
}
}
go attachStream("stdout", stdout, cStdout)
go attachStream("stderr", stderr, cStderr)
return promise.Go(func() error {
wg.Wait()
close(errors)
for err := range errors {
if err != nil {
return err
}
}
return nil
})
}
// Code c/c from io.Copy() modified to handle escape sequence
func copyEscapable(dst io.Writer, src io.ReadCloser, keys []byte) (written int64, err error) {
if len(keys) == 0 {
// Default keys : ctrl-p ctrl-q
keys = []byte{16, 17}
}
buf := make([]byte, 32*1024)
for {
nr, er := src.Read(buf)
if nr > 0 {
// ---- Docker addition
for i, key := range keys {
if nr != 1 || buf[0] != key {
break
}
if i == len(keys)-1 {
if err := src.Close(); err != nil {
return 0, err
}
return 0, nil
}
nr, er = src.Read(buf)
}
// ---- End of docker
nw, ew := dst.Write(buf[0:nr])
if nw > 0 {
written += int64(nw)
}
if ew != nil {
err = ew
break
}
if nr != nw {
err = io.ErrShortWrite
break
}
}
if er == io.EOF {
break
}
if er != nil {
err = er
break
}
}
return written, err
}
// ShouldRestart decides whether the daemon should restart the container or not.
// This is based on the container's restart policy.
func (container *Container) ShouldRestart() bool {
return container.HostConfig.RestartPolicy.Name == "always" ||
(container.HostConfig.RestartPolicy.Name == "unless-stopped" && !container.HasBeenManuallyStopped) ||
(container.HostConfig.RestartPolicy.Name == "on-failure" && container.ExitCode != 0)
}
// AddBindMountPoint adds a new bind mount point configuration to the container.
func (container *Container) AddBindMountPoint(name, source, destination string, rw bool) {
container.MountPoints[destination] = &volume.MountPoint{
Name: name,
Source: source,
Destination: destination,
RW: rw,
}
}
// AddLocalMountPoint adds a new local mount point configuration to the container.
func (container *Container) AddLocalMountPoint(name, destination string, rw bool) {
container.MountPoints[destination] = &volume.MountPoint{
Name: name,
Driver: volume.DefaultDriverName,
Destination: destination,
RW: rw,
}
}
// AddMountPointWithVolume adds a new mount point configured with a volume to the container.
func (container *Container) AddMountPointWithVolume(destination string, vol volume.Volume, rw bool) {
container.MountPoints[destination] = &volume.MountPoint{
Name: vol.Name(),
Driver: vol.DriverName(),
Destination: destination,
RW: rw,
Volume: vol,
}
}
// IsDestinationMounted checks whether a path is mounted on the container or not.
func (container *Container) IsDestinationMounted(destination string) bool {
return container.MountPoints[destination] != nil
}
// StopSignal returns the signal used to stop the container.
func (container *Container) StopSignal() int {
var stopSignal syscall.Signal
if container.Config.StopSignal != "" {
stopSignal, _ = signal.ParseSignal(container.Config.StopSignal)
}
if int(stopSignal) == 0 {
stopSignal, _ = signal.ParseSignal(signal.DefaultStopSignal)
}
return int(stopSignal)
}
// InitDNSHostConfig ensures that the dns fields are never nil.
// New containers don't ever have those fields nil,
// but pre created containers can still have those nil values.
// The non-recommended host configuration in the start api can
// make these fields nil again, this corrects that issue until
// we remove that behavior for good.
// See https://github.com/docker/docker/pull/17779
// for a more detailed explanation on why we don't want that.
func (container *Container) InitDNSHostConfig() {
container.Lock()
defer container.Unlock()
if container.HostConfig.DNS == nil {
container.HostConfig.DNS = make([]string, 0)
}
if container.HostConfig.DNSSearch == nil {
container.HostConfig.DNSSearch = make([]string, 0)
}
if container.HostConfig.DNSOptions == nil {
container.HostConfig.DNSOptions = make([]string, 0)
}
}
// UpdateMonitor updates monitor configure for running container
func (container *Container) UpdateMonitor(restartPolicy containertypes.RestartPolicy) {
monitor := container.monitor
// No need to update monitor if container hasn't got one
// monitor will be generated correctly according to container
if monitor == nil {
return
}
monitor.mux.Lock()
// to check whether restart policy has changed.
if restartPolicy.Name != "" && !monitor.restartPolicy.IsSame(&restartPolicy) {
monitor.restartPolicy = restartPolicy
}
monitor.mux.Unlock()
}