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moby--moby/libcontainerd/container_linux.go

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package libcontainerd
import (
"encoding/json"
"io"
"io/ioutil"
"os"
"path/filepath"
"syscall"
"time"
"github.com/Sirupsen/logrus"
containerd "github.com/docker/containerd/api/grpc/types"
"github.com/docker/docker/restartmanager"
"github.com/opencontainers/specs/specs-go"
"golang.org/x/net/context"
)
type container struct {
containerCommon
// Platform specific fields are below here.
pauseMonitor
oom bool
runtime string
runtimeArgs []string
}
type runtime struct {
path string
args []string
}
// WithRuntime sets the runtime to be used for the created container
func WithRuntime(path string, args []string) CreateOption {
return runtime{path, args}
}
func (rt runtime) Apply(p interface{}) error {
if pr, ok := p.(*container); ok {
pr.runtime = rt.path
pr.runtimeArgs = rt.args
}
return nil
}
func (ctr *container) clean() error {
if os.Getenv("LIBCONTAINERD_NOCLEAN") == "1" {
return nil
}
if _, err := os.Lstat(ctr.dir); err != nil {
if os.IsNotExist(err) {
return nil
}
return err
}
if err := os.RemoveAll(ctr.dir); err != nil {
return err
}
return nil
}
// cleanProcess removes the fifos used by an additional process.
// Caller needs to lock container ID before calling this method.
func (ctr *container) cleanProcess(id string) {
if p, ok := ctr.processes[id]; ok {
for _, i := range []int{syscall.Stdin, syscall.Stdout, syscall.Stderr} {
if err := os.Remove(p.fifo(i)); err != nil {
logrus.Warnf("failed to remove %v for process %v: %v", p.fifo(i), id, err)
}
}
}
delete(ctr.processes, id)
}
func (ctr *container) spec() (*specs.Spec, error) {
var spec specs.Spec
dt, err := ioutil.ReadFile(filepath.Join(ctr.dir, configFilename))
if err != nil {
return nil, err
}
if err := json.Unmarshal(dt, &spec); err != nil {
return nil, err
}
return &spec, nil
}
func (ctr *container) start() error {
spec, err := ctr.spec()
if err != nil {
return nil
}
iopipe, err := ctr.openFifos(spec.Process.Terminal)
if err != nil {
return err
}
r := &containerd.CreateContainerRequest{
Id: ctr.containerID,
BundlePath: ctr.dir,
Stdin: ctr.fifo(syscall.Stdin),
Stdout: ctr.fifo(syscall.Stdout),
Stderr: ctr.fifo(syscall.Stderr),
// check to see if we are running in ramdisk to disable pivot root
NoPivotRoot: os.Getenv("DOCKER_RAMDISK") != "",
Runtime: ctr.runtime,
RuntimeArgs: ctr.runtimeArgs,
}
ctr.client.appendContainer(ctr)
resp, err := ctr.client.remote.apiClient.CreateContainer(context.Background(), r)
if err != nil {
ctr.closeFifos(iopipe)
return err
}
ctr.startedAt = time.Now()
if err := ctr.client.backend.AttachStreams(ctr.containerID, *iopipe); err != nil {
return err
}
ctr.systemPid = systemPid(resp.Container)
return ctr.client.backend.StateChanged(ctr.containerID, StateInfo{
CommonStateInfo: CommonStateInfo{
State: StateStart,
Pid: ctr.systemPid,
}})
}
func (ctr *container) newProcess(friendlyName string) *process {
return &process{
dir: ctr.dir,
processCommon: processCommon{
containerID: ctr.containerID,
friendlyName: friendlyName,
client: ctr.client,
},
}
}
func (ctr *container) handleEvent(e *containerd.Event) error {
ctr.client.lock(ctr.containerID)
defer ctr.client.unlock(ctr.containerID)
switch e.Type {
case StateExit, StatePause, StateResume, StateOOM:
st := StateInfo{
CommonStateInfo: CommonStateInfo{
State: e.Type,
ExitCode: e.Status,
},
OOMKilled: e.Type == StateExit && ctr.oom,
}
if e.Type == StateOOM {
ctr.oom = true
}
if e.Type == StateExit && e.Pid != InitFriendlyName {
st.ProcessID = e.Pid
st.State = StateExitProcess
}
if st.State == StateExit && ctr.restartManager != nil {
restart, wait, err := ctr.restartManager.ShouldRestart(e.Status, false, time.Since(ctr.startedAt))
if err != nil {
logrus.Warnf("container %s %v", ctr.containerID, err)
} else if restart {
st.State = StateRestart
ctr.restarting = true
ctr.client.deleteContainer(e.Id)
go func() {
err := <-wait
ctr.client.lock(ctr.containerID)
defer ctr.client.unlock(ctr.containerID)
ctr.restarting = false
if err != nil {
st.State = StateExit
ctr.clean()
ctr.client.q.append(e.Id, func() {
if err := ctr.client.backend.StateChanged(e.Id, st); err != nil {
logrus.Error(err)
}
})
if err != restartmanager.ErrRestartCanceled {
logrus.Error(err)
}
} else {
ctr.start()
}
}()
}
}
// Remove process from list if we have exited
// We need to do so here in case the Message Handler decides to restart it.
switch st.State {
case StateExit:
ctr.clean()
ctr.client.deleteContainer(e.Id)
case StateExitProcess:
ctr.cleanProcess(st.ProcessID)
}
ctr.client.q.append(e.Id, func() {
if err := ctr.client.backend.StateChanged(e.Id, st); err != nil {
logrus.Error(err)
}
if e.Type == StatePause || e.Type == StateResume {
ctr.pauseMonitor.handle(e.Type)
}
if e.Type == StateExit {
if en := ctr.client.getExitNotifier(e.Id); en != nil {
en.close()
}
}
})
default:
logrus.Debugf("event unhandled: %+v", e)
}
return nil
}
// discardFifos attempts to fully read the container fifos to unblock processes
// that may be blocked on the writer side.
func (ctr *container) discardFifos() {
for _, i := range []int{syscall.Stdout, syscall.Stderr} {
f := ctr.fifo(i)
c := make(chan struct{})
go func() {
close(c) // this channel is used to not close the writer too early, before readonly open has been called.
io.Copy(ioutil.Discard, openReaderFromFifo(f))
}()
<-c
closeReaderFifo(f) // avoid blocking permanently on open if there is no writer side
}
}