wings/environment/docker/container.go

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package docker
import (
"bufio"
"context"
"fmt"
"io"
"strconv"
"strings"
"time"
"emperror.dev/errors"
"github.com/apex/log"
"github.com/buger/jsonparser"
"github.com/docker/docker/api/types"
"github.com/docker/docker/api/types/container"
"github.com/docker/docker/api/types/mount"
"github.com/docker/docker/client"
"github.com/docker/docker/daemon/logger/local"
"github.com/pterodactyl/wings/config"
"github.com/pterodactyl/wings/environment"
"github.com/pterodactyl/wings/system"
)
var ErrNotAttached = errors.Sentinel("not attached to instance")
// A custom console writer that allows us to keep a function blocked until the
// given stream is properly closed. This does nothing special, only exists to
// make a noop io.Writer.
type noopWriter struct{}
var _ io.Writer = noopWriter{}
// Implement the required Write function to satisfy the io.Writer interface.
func (nw noopWriter) Write(b []byte) (int, error) {
return len(b), nil
}
// Attach attaches to the docker container itself and ensures that we can pipe
// data in and out of the process stream. This should always be called before
// you have started the container, but after you've ensured it exists.
//
// Calling this function will poll resources for the container in the background
// until the container is stopped. The context provided to this function is used
// for the purposes of attaching to the container, a seecond context is created
// within the function for managing polling.
func (e *Environment) Attach(ctx context.Context) error {
if e.IsAttached() {
return nil
}
if err := e.followOutput(); err != nil {
return err
}
opts := types.ContainerAttachOptions{
Stdin: true,
Stdout: true,
Stderr: true,
Stream: true,
}
// Set the stream again with the container.
if st, err := e.client.ContainerAttach(ctx, e.Id, opts); err != nil {
return err
} else {
e.SetStream(&st)
}
go func() {
// Don't use the context provided to the function, that'll cause the polling to
// exit unexpectedly. We want a custom context for this, the one passed to the
// function is to avoid a hang situation when trying to attach to a container.
pollCtx, cancel := context.WithCancel(context.Background())
defer cancel()
defer e.stream.Close()
defer func() {
e.SetState(environment.ProcessOfflineState)
e.SetStream(nil)
}()
go func() {
if err := e.pollResources(pollCtx); err != nil {
if !errors.Is(err, context.Canceled) {
e.log().WithField("error", err).Error("error during environment resource polling")
} else {
e.log().Warn("stopping server resource polling: context canceled")
}
}
}()
// Block the completion of this routine until the container is no longer running. This allows
// the pollResources function to run until it needs to be stopped. Because the container
// can be polled for resource usage, even when stopped, we need to have this logic present
// in order to cancel the context and therefore stop the routine that is spawned.
//
// For now, DO NOT use client#ContainerWait from the Docker package. There is a nasty
// bug causing containers to hang on deletion and cause servers to lock up on the system.
//
// This weird code isn't intuitive, but it keeps the function from ending until the container
// is stopped and therefore the stream reader ends up closed.
// @see https://github.com/moby/moby/issues/41827
c := new(noopWriter)
if _, err := io.Copy(c, e.stream.Reader); err != nil {
e.log().WithField("error", err).Error("could not copy from environment stream to noop writer")
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}
}()
return nil
}
// InSituUpdate performs an in-place update of the Docker container's resource
// limits without actually making any changes to the operational state of the
// container. This allows memory, cpu, and IO limitations to be adjusted on the
// fly for individual instances.
func (e *Environment) InSituUpdate() error {
ctx, cancel := context.WithTimeout(context.Background(), time.Second*10)
defer cancel()
if _, err := e.ContainerInspect(ctx); err != nil {
// If the container doesn't exist for some reason there really isn't anything
// we can do to fix that in this process (it doesn't make sense at least). In those
// cases just return without doing anything since we still want to save the configuration
// to the disk.
//
// We'll let a boot process make modifications to the container if needed at this point.
if client.IsErrNotFound(err) {
return nil
}
return errors.Wrap(err, "environment/docker: could not inspect container")
}
// CPU pinning cannot be removed once it is applied to a container. The same is true
// for removing memory limits, a container must be re-created.
//
// @see https://github.com/moby/moby/issues/41946
if _, err := e.client.ContainerUpdate(ctx, e.Id, container.UpdateConfig{
Resources: e.Configuration.Limits().AsContainerResources(),
}); err != nil {
return errors.Wrap(err, "environment/docker: could not update container")
}
return nil
}
// Create creates a new container for the server using all the data that is
// currently available for it. If the container already exists it will be
// returned.
func (e *Environment) Create() error {
// If the container already exists don't hit the user with an error, just return
// the current information about it which is what we would do when creating the
// container anyways.
if _, err := e.ContainerInspect(context.Background()); err == nil {
return nil
} else if !client.IsErrNotFound(err) {
return errors.Wrap(err, "environment/docker: failed to inspect container")
}
// Try to pull the requested image before creating the container.
if err := e.ensureImageExists(e.meta.Image); err != nil {
return errors.WithStackIf(err)
}
a := e.Configuration.Allocations()
evs := e.Configuration.EnvironmentVariables()
for i, v := range evs {
// Convert 127.0.0.1 to the pterodactyl0 network interface if the environment is Docker
// so that the server operates as expected.
if v == "SERVER_IP=127.0.0.1" {
evs[i] = "SERVER_IP=" + config.Get().Docker.Network.Interface
}
}
conf := &container.Config{
Hostname: e.Id,
Domainname: config.Get().Docker.Domainname,
User: strconv.Itoa(config.Get().System.User.Uid) + ":" + strconv.Itoa(config.Get().System.User.Gid),
AttachStdin: true,
AttachStdout: true,
AttachStderr: true,
OpenStdin: true,
Tty: true,
ExposedPorts: a.Exposed(),
Image: strings.TrimPrefix(e.meta.Image, "~"),
Env: e.Configuration.EnvironmentVariables(),
Labels: map[string]string{
"Service": "Pterodactyl",
"ContainerType": "server_process",
},
}
tmpfsSize := strconv.Itoa(int(config.Get().Docker.TmpfsSize))
hostConf := &container.HostConfig{
PortBindings: a.DockerBindings(),
// Configure the mounts for this container. First mount the server data directory
// into the container as an r/w bind.
Mounts: e.convertMounts(),
// Configure the /tmp folder mapping in containers. This is necessary for some
// games that need to make use of it for downloads and other installation processes.
Tmpfs: map[string]string{
"/tmp": "rw,exec,nosuid,size=" + tmpfsSize + "M",
},
// Define resource limits for the container based on the data passed through
// from the Panel.
Resources: e.Configuration.Limits().AsContainerResources(),
DNS: config.Get().Docker.Network.Dns,
// Configure logging for the container to make it easier on the Daemon to grab
// the server output. Ensure that we don't use too much space on the host machine
// since we only need it for the last few hundred lines of output and don't care
// about anything else in it.
LogConfig: container.LogConfig{
Type: local.Name,
Config: map[string]string{
"max-size": "5m",
"max-file": "1",
"compress": "false",
"mode": "non-blocking",
},
},
SecurityOpt: []string{"no-new-privileges"},
ReadonlyRootfs: true,
CapDrop: []string{
"setpcap", "mknod", "audit_write", "net_raw", "dac_override",
"fowner", "fsetid", "net_bind_service", "sys_chroot", "setfcap",
},
NetworkMode: container.NetworkMode(config.Get().Docker.Network.Mode),
}
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if _, err := e.client.ContainerCreate(context.Background(), conf, hostConf, nil, nil, e.Id); err != nil {
return errors.Wrap(err, "environment/docker: failed to create container")
}
return nil
}
// Destroy will remove the Docker container from the server. If the container
// is currently running it will be forcibly stopped by Docker.
func (e *Environment) Destroy() error {
// We set it to stopping than offline to prevent crash detection from being triggered.
e.SetState(environment.ProcessStoppingState)
err := e.client.ContainerRemove(context.Background(), e.Id, types.ContainerRemoveOptions{
RemoveVolumes: true,
RemoveLinks: false,
Force: true,
})
e.SetState(environment.ProcessOfflineState)
// Don't trigger a destroy failure if we try to delete a container that does not
// exist on the system. We're just a step ahead of ourselves in that case.
//
// @see https://github.com/pterodactyl/panel/issues/2001
if err != nil && client.IsErrNotFound(err) {
return nil
}
return err
}
// SendCommand sends the specified command to the stdin of the running container
// instance. There is no confirmation that this data is sent successfully, only
// that it gets pushed into the stdin.
func (e *Environment) SendCommand(c string) error {
if !e.IsAttached() {
return errors.Wrap(ErrNotAttached, "environment/docker: cannot send command to container")
}
e.mu.RLock()
defer e.mu.RUnlock()
// If the command being processed is the same as the process stop command then we
// want to mark the server as entering the stopping state otherwise the process will
// stop and Wings will think it has crashed and attempt to restart it.
if e.meta.Stop.Type == "command" && c == e.meta.Stop.Value {
e.SetState(environment.ProcessStoppingState)
}
_, err := e.stream.Conn.Write([]byte(c + "\n"))
return errors.Wrap(err, "environment/docker: could not write to container stream")
}
// Readlog reads the log file for the server. This does not care if the server
// is running or not, it will simply try to read the last X bytes of the file
// and return them.
func (e *Environment) Readlog(lines int) ([]string, error) {
r, err := e.client.ContainerLogs(context.Background(), e.Id, types.ContainerLogsOptions{
ShowStdout: true,
ShowStderr: true,
Tail: strconv.Itoa(lines),
})
if err != nil {
return nil, errors.WithStack(err)
}
defer r.Close()
var out []string
scanner := bufio.NewScanner(r)
for scanner.Scan() {
out = append(out, scanner.Text())
}
return out, nil
}
// Attaches to the log for the container. This avoids us missing crucial output
// that happens in the split seconds before the code moves from 'Starting' to
// 'Attaching' on the process.
func (e *Environment) followOutput() error {
if exists, err := e.Exists(); !exists {
if err != nil {
return err
}
return errors.New(fmt.Sprintf("no such container: %s", e.Id))
}
opts := types.ContainerLogsOptions{
ShowStderr: true,
ShowStdout: true,
Follow: true,
Since: time.Now().Format(time.RFC3339),
}
reader, err := e.client.ContainerLogs(context.Background(), e.Id, opts)
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if err != nil {
return err
}
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go e.scanOutput(reader)
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return nil
}
func (e *Environment) scanOutput(reader io.ReadCloser) {
defer reader.Close()
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if err := system.ScanReader(reader, func(v []byte) {
e.logCallbackMx.Lock()
defer e.logCallbackMx.Unlock()
e.logCallback(v)
}); err != nil && err != io.EOF {
log.WithField("error", err).WithField("container_id", e.Id).Warn("error processing scanner line in console output")
return
}
// Return here if the server is offline or currently stopping.
if e.State() == environment.ProcessStoppingState || e.State() == environment.ProcessOfflineState {
return
}
// Close the current reader before starting a new one, the defer will still run,
// but it will do nothing if we already closed the stream.
_ = reader.Close()
// Start following the output of the server again.
go e.followOutput()
}
// Pulls the image from Docker. If there is an error while pulling the image
// from the source but the image already exists locally, we will report that
// error to the logger but continue with the process.
//
// The reasoning behind this is that Quay has had some serious outages as of
// late, and we don't need to block all the servers from booting just because
// of that. I'd imagine in a lot of cases an outage shouldn't affect users too
// badly. It'll at least keep existing servers working correctly if anything.
func (e *Environment) ensureImageExists(image string) error {
e.Events().Publish(environment.DockerImagePullStarted, "")
defer e.Events().Publish(environment.DockerImagePullCompleted, "")
// Images prefixed with a ~ are local images that we do not need to try and pull.
if strings.HasPrefix(image, "~") {
return nil
}
// Give it up to 15 minutes to pull the image. I think this should cover 99.8% of cases where an
// image pull might fail. I can't imagine it will ever take more than 15 minutes to fully pull
// an image. Let me know when I am inevitably wrong here...
ctx, cancel := context.WithTimeout(context.Background(), time.Minute*15)
defer cancel()
// Get a registry auth configuration from the config.
var registryAuth *config.RegistryConfiguration
for registry, c := range config.Get().Docker.Registries {
if !strings.HasPrefix(image, registry) {
continue
}
log.WithField("registry", registry).Debug("using authentication for registry")
registryAuth = &c
break
}
// Get the ImagePullOptions.
imagePullOptions := types.ImagePullOptions{All: false}
if registryAuth != nil {
b64, err := registryAuth.Base64()
if err != nil {
log.WithError(err).Error("failed to get registry auth credentials")
}
// b64 is a string so if there is an error it will just be empty, not nil.
imagePullOptions.RegistryAuth = b64
}
out, err := e.client.ImagePull(ctx, image, imagePullOptions)
if err != nil {
images, ierr := e.client.ImageList(ctx, types.ImageListOptions{})
if ierr != nil {
// Well damn, something has gone really wrong here, just go ahead and abort there
// isn't much anything we can do to try and self-recover from this.
return errors.Wrap(ierr, "environment/docker: failed to list images")
}
for _, img := range images {
for _, t := range img.RepoTags {
if t != image {
continue
}
log.WithFields(log.Fields{
"image": image,
"container_id": e.Id,
"err": err.Error(),
}).Warn("unable to pull requested image from remote source, however the image exists locally")
// Okay, we found a matching container image, in that case just go ahead and return
// from this function, since there is nothing else we need to do here.
return nil
}
}
return errors.Wrapf(err, "environment/docker: failed to pull \"%s\" image for server", image)
}
defer out.Close()
log.WithField("image", image).Debug("pulling docker image... this could take a bit of time")
// I'm not sure what the best approach here is, but this will block execution until the image
// is done being pulled, which is what we need.
scanner := bufio.NewScanner(out)
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for scanner.Scan() {
b := scanner.Bytes()
status, _ := jsonparser.GetString(b, "status")
progress, _ := jsonparser.GetString(b, "progress")
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e.Events().Publish(environment.DockerImagePullStatus, status+" "+progress)
}
if err := scanner.Err(); err != nil {
return err
}
log.WithField("image", image).Debug("completed docker image pull")
return nil
}
func (e *Environment) convertMounts() []mount.Mount {
var out []mount.Mount
for _, m := range e.Configuration.Mounts() {
out = append(out, mount.Mount{
Type: mount.TypeBind,
Source: m.Source,
Target: m.Target,
ReadOnly: m.ReadOnly,
})
}
return out
}