package server import ( "bufio" "bytes" "context" "encoding/json" "fmt" "github.com/apex/log" "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/jsonfilelog" "github.com/docker/go-connections/nat" "github.com/pkg/errors" "github.com/pterodactyl/wings/api" "github.com/pterodactyl/wings/config" "io" "os" "strconv" "strings" "time" ) // Defines the base environment for Docker instances running through Wings. type DockerEnvironment struct { Server *Server // The Docker client being used for this instance. Client *client.Client // Tracks if we are currently attached to the server container. This allows us to attach // once and then just use that attachment to stream logs out of the server and also stream // commands back into it without constantly attaching and detaching. attached bool // Controls the hijacked response stream which exists only when we're attached to // the running container instance. stream types.HijackedResponse // Holds the stats stream used by the polling commands so that we can easily close // it out. stats io.ReadCloser } // Creates a new base Docker environment. A server must still be attached to it. func NewDockerEnvironment(server *Server) error { cli, err := client.NewClientWithOpts(client.FromEnv) if err != nil { return err } server.Environment = &DockerEnvironment{ Server: server, Client: cli, } return nil } // Ensure that the Docker environment is always implementing all of the methods // from the base environment interface. var _ Environment = (*DockerEnvironment)(nil) // Returns the name of the environment. func (d *DockerEnvironment) Type() string { return "docker" } // Determines if the container exists in this environment. func (d *DockerEnvironment) Exists() (bool, error) { _, err := d.Client.ContainerInspect(context.Background(), d.Server.Uuid) if err != nil { // If this error is because the container instance wasn't found via Docker we // can safely ignore the error and just return false. if client.IsErrNotFound(err) { return false, nil } return false, err } return true, nil } // Determines if the server's docker container is currently running. If there is no container // present, an error will be raised (since this shouldn't be a case that ever happens under // correctly developed circumstances). // // You can confirm if the instance wasn't found by using client.IsErrNotFound from the Docker // API. // // @see docker/client/errors.go func (d *DockerEnvironment) IsRunning() (bool, error) { ctx := context.Background() c, err := d.Client.ContainerInspect(ctx, d.Server.Uuid) if err != nil { return false, err } return c.State.Running, nil } // 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 (d *DockerEnvironment) InSituUpdate() error { if _, err := d.Client.ContainerInspect(context.Background(), d.Server.Uuid); 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.WithStack(err) } ctx, _ := context.WithTimeout(context.Background(), time.Second * 10) u := container.UpdateConfig{ Resources: d.getResourcesForServer(), } d.Server.Log().WithField("limits", fmt.Sprintf("%+v", u.Resources)).Debug("updating server container on-the-fly with passed limits") if _, err := d.Client.ContainerUpdate(ctx, d.Server.Uuid, u); err != nil { return errors.WithStack(err) } return nil } // Run before the container starts and get the process configuration from the Panel. // This is important since we use this to check configuration files as well as ensure // we always have the latest version of an egg available for server processes. // // This process will also confirm that the server environment exists and is in a bootable // state. This ensures that unexpected container deletion while Wings is running does // not result in the server becoming unbootable. func (d *DockerEnvironment) OnBeforeStart() error { d.Server.Log().Info("syncing server configuration with panel") if err := d.Server.Sync(); err != nil { return err } if !d.Server.Filesystem.HasSpaceAvailable() { return errors.New("cannot start server, not enough disk space available") } // Always destroy and re-create the server container to ensure that synced data from // the Panel is used. if err := d.Client.ContainerRemove(context.Background(), d.Server.Uuid, types.ContainerRemoveOptions{RemoveVolumes: true}); err != nil { if !client.IsErrNotFound(err) { return err } } // The Create() function will check if the container exists in the first place, and if // so just silently return without an error. Otherwise, it will try to create the necessary // container and data storage directory. // // This won't actually run an installation process however, it is just here to ensure the // environment gets created properly if it is missing and the server is started. We're making // an assumption that all of the files will still exist at this point. if err := d.Create(); err != nil { return err } return nil } // Starts the server environment and begins piping output to the event listeners for the // console. If a container does not exist, or needs to be rebuilt that will happen in the // call to OnBeforeStart(). func (d *DockerEnvironment) Start() error { sawError := false // If sawError is set to true there was an error somewhere in the pipeline that // got passed up, but we also want to ensure we set the server to be offline at // that point. defer func() { if sawError { // If we don't set it to stopping first, you'll trigger crash detection which // we don't want to do at this point since it'll just immediately try to do the // exact same action that lead to it crashing in the first place... d.Server.SetState(ProcessStoppingState) d.Server.SetState(ProcessOfflineState) } }() // If the server is suspended the user shouldn't be able to boot it, in those cases // return a suspension error and let the calling area handle the issue. // // Theoretically you'd have the Panel handle all of this logic, but we cannot do that // because we allow the websocket to control the server power state as well, so we'll // need to handle that action in here. if d.Server.Suspended { return &suspendedError{} } if c, err := d.Client.ContainerInspect(context.Background(), d.Server.Uuid); err != nil { // Do nothing if the container is not found, we just don't want to continue // to the next block of code here. This check was inlined here to guard againt // a nil-pointer when checking c.State below. // // @see https://github.com/pterodactyl/panel/issues/2000 if !client.IsErrNotFound(err) { return errors.WithStack(err) } } else { // If the server is running update our internal state and continue on with the attach. if c.State.Running { d.Server.SetState(ProcessRunningState) return d.Attach() } // Truncate the log file so we don't end up outputting a bunch of useless log information // to the websocket and whatnot. Check first that the path and file exist before trying // to truncate them. if _, err := os.Stat(c.LogPath); err == nil { if err := os.Truncate(c.LogPath, 0); err != nil { return errors.WithStack(err) } } } d.Server.SetState(ProcessStartingState) // Set this to true for now, we will set it to false once we reach the // end of this chain. sawError = true // Run the before start function and wait for it to finish. This will validate that the container // exists on the system, and rebuild the container if that is required for server booting to // occur. if err := d.OnBeforeStart(); err != nil { return errors.WithStack(err) } // Update the configuration files defined for the server before beginning the boot process. // This process executes a bunch of parallel updates, so we just block until that process // is completed. Any errors as a result of this will just be bubbled out in the logger, // we don't need to actively do anything about it at this point, worst comes to worst the // server starts in a weird state and the user can manually adjust. d.Server.UpdateConfigurationFiles() // Reset the permissions on files for the server before actually trying // to start it. if err := d.Server.Filesystem.Chown("/"); err != nil { return errors.WithStack(err) } ctx, _ := context.WithTimeout(context.Background(), time.Second * 10) if err := d.Client.ContainerStart(ctx, d.Server.Uuid, types.ContainerStartOptions{}); err != nil { return errors.WithStack(err) } // No errors, good to continue through. sawError = false return d.Attach() } // Stops the container that the server is running in. This will allow up to 10 // seconds to pass before a failure occurs. func (d *DockerEnvironment) Stop() error { stop := d.Server.processConfiguration.Stop if stop.Type == api.ProcessStopSignal { return d.Terminate(os.Kill) } d.Server.SetState(ProcessStoppingState) if stop.Type == api.ProcessStopCommand { return d.SendCommand(stop.Value) } t := time.Second * 10 return d.Client.ContainerStop(context.Background(), d.Server.Uuid, &t) } // Attempts to gracefully stop a server using the defined stop command. If the server // does not stop after seconds have passed, an error will be returned, or the instance // will be terminated forcefully depending on the value of the second argument. func (d *DockerEnvironment) WaitForStop(seconds int, terminate bool) error { if d.Server.GetState() == ProcessOfflineState { return nil } if err := d.Stop(); err != nil { return errors.WithStack(err) } ctx, cancel := context.WithTimeout(context.Background(), time.Duration(seconds)*time.Second) defer cancel() // Block the return of this function until the container as been marked as no // longer running. If this wait does not end by the time seconds have passed, // attempt to terminate the container, or return an error. ok, errChan := d.Client.ContainerWait(ctx, d.Server.Uuid, container.WaitConditionNotRunning) select { case <-ctx.Done(): if ctxErr := ctx.Err(); ctxErr != nil { if terminate { return d.Terminate(os.Kill) } return errors.WithStack(ctxErr) } case err := <-errChan: if err != nil { return errors.WithStack(err) } case <-ok: } return nil } // Forcefully terminates the container using the signal passed through. func (d *DockerEnvironment) Terminate(signal os.Signal) error { ctx := context.Background() c, err := d.Client.ContainerInspect(ctx, d.Server.Uuid) if err != nil { return errors.WithStack(err) } if !c.State.Running { return nil } d.Server.SetState(ProcessStoppingState) return d.Client.ContainerKill( ctx, d.Server.Uuid, strings.TrimSuffix(strings.TrimPrefix(signal.String(), "signal "), "ed"), ) } // Remove the Docker container from the machine. If the container is currently running // it will be forcibly stopped by Docker. func (d *DockerEnvironment) Destroy() error { ctx := context.Background() // Avoid crash detection firing off. d.Server.SetState(ProcessStoppingState) err := d.Client.ContainerRemove(ctx, d.Server.Uuid, types.ContainerRemoveOptions{ RemoveVolumes: true, RemoveLinks: false, Force: true, }) // 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 } // Determine the container exit state and return the exit code and wether or not // the container was killed by the OOM killer. func (d *DockerEnvironment) ExitState() (uint32, bool, error) { c, err := d.Client.ContainerInspect(context.Background(), d.Server.Uuid) if err != nil { // I'm not entirely sure how this can happen to be honest. I tried deleting a // container _while_ a server was running and wings gracefully saw the crash and // created a new container for it. // // However, someone reported an error in Discord about this scenario happening, // so I guess this should prevent it? They didn't tell me how they caused it though // so thats a mystery that will have to go unsolved. // // @see https://github.com/pterodactyl/panel/issues/2003 if client.IsErrNotFound(err) { return 1, false, nil } return 0, false, errors.WithStack(err) } return uint32(c.State.ExitCode), c.State.OOMKilled, nil } // Attaches to the docker container itself and ensures that we can pipe data in and out // of the process stream. This should not be used for reading console data as you *will* // miss important output at the beginning because of the time delay with attaching to the // output. func (d *DockerEnvironment) Attach() error { if d.attached { return nil } if err := d.FollowConsoleOutput(); err != nil { return errors.WithStack(err) } ctx := context.Background() var err error d.stream, err = d.Client.ContainerAttach(ctx, d.Server.Uuid, types.ContainerAttachOptions{ Stdin: true, Stdout: true, Stderr: true, Stream: true, }) if err != nil { return errors.WithStack(err) } console := Console{ Server: d.Server, } d.attached = true go func() { if err := d.EnableResourcePolling(); err != nil { d.Server.Log().WithField("error", errors.WithStack(err)).Warn("failed to enable resource polling on server") } }() go func() { defer d.stream.Close() defer func() { d.Server.SetState(ProcessOfflineState) d.attached = false }() io.Copy(console, d.stream.Reader) }() return nil } // Attaches to the log for the container. This avoids us missing cruicial output that // happens in the split seconds before the code moves from 'Starting' to 'Attaching' // on the process. func (d *DockerEnvironment) FollowConsoleOutput() error { if exists, err := d.Exists(); !exists { if err != nil { return errors.WithStack(err) } return errors.New(fmt.Sprintf("no such container: %s", d.Server.Uuid)) } ctx := context.Background() opts := types.ContainerLogsOptions{ ShowStderr: true, ShowStdout: true, Follow: true, Since: time.Now().Format(time.RFC3339), } reader, err := d.Client.ContainerLogs(ctx, d.Server.Uuid, opts) go func(r io.ReadCloser) { defer r.Close() s := bufio.NewScanner(r) for s.Scan() { d.Server.Events().Publish(ConsoleOutputEvent, s.Text()) } if err := s.Err(); err != nil { d.Server.Log().WithField("error", err).Warn("error processing scanner line in console output") } }(reader) return errors.WithStack(err) } // Enables resource polling on the docker instance. Except we aren't actually polling Docker for this // information, instead just sit there with an async process that lets Docker stream all of this data // to us automatically. func (d *DockerEnvironment) EnableResourcePolling() error { if d.Server.GetState() == ProcessOfflineState { return errors.New("cannot enable resource polling on a server that is not running") } ctx := context.Background() stats, err := d.Client.ContainerStats(ctx, d.Server.Uuid, true) if err != nil { return errors.WithStack(err) } d.stats = stats.Body dec := json.NewDecoder(d.stats) go func(s *Server) { for { var v *types.StatsJSON if err := dec.Decode(&v); err != nil { if err != io.EOF { d.Server.Log().WithField("error", err).Warn("encountered error processing server stats, stopping collection") } d.DisableResourcePolling() return } // Disable collection if the server is in an offline state and this process is // still running. if s.GetState() == ProcessOfflineState { d.DisableResourcePolling() return } s.Resources.CpuAbsolute = s.Resources.CalculateAbsoluteCpu(&v.PreCPUStats, &v.CPUStats) s.Resources.Memory = s.Resources.CalculateDockerMemory(v.MemoryStats) s.Resources.MemoryLimit = v.MemoryStats.Limit // Why you ask? This already has the logic for caching disk space in use and then // also handles pushing that value to the resources object automatically. s.Filesystem.HasSpaceAvailable() for _, nw := range v.Networks { s.Resources.Network.RxBytes += nw.RxBytes s.Resources.Network.TxBytes += nw.TxBytes } b, _ := json.Marshal(s.Resources) s.Events().Publish(StatsEvent, string(b)) } }(d.Server) return nil } // Closes the stats stream for a server process. func (d *DockerEnvironment) DisableResourcePolling() error { if d.stats == nil { return nil } err := d.stats.Close() d.Server.Resources.CpuAbsolute = 0 d.Server.Resources.Memory = 0 d.Server.Resources.Network.TxBytes = 0 d.Server.Resources.Network.RxBytes = 0 return errors.WithStack(err) } // 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 of 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. // // @todo handle authorization & local images func (d *DockerEnvironment) ensureImageExists(c *client.Client) error { // 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, _ := context.WithTimeout(context.Background(), time.Minute*15) out, err := c.ImagePull(ctx, d.Server.Container.Image, types.ImagePullOptions{All: false}) if err != nil { images, ierr := c.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 ierr } for _, img := range images { for _, t := range img.RepoTags { if t == d.Server.Container.Image { d.Server.Log().WithFields(log.Fields{ "image": d.Server.Container.Image, "error": errors.New(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 err } defer out.Close() log.WithField("image", d.Server.Container.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) for scanner.Scan() { continue } if err := scanner.Err(); err != nil { return err } return nil } // Creates a new container for the server using all of the data that is currently // available for it. If the container already exists it will be returned. func (d *DockerEnvironment) Create() error { ctx := context.Background() cli, err := client.NewClientWithOpts(client.FromEnv) if err != nil { return errors.WithStack(err) } // Ensure the data directory exists before getting too far through this process. if err := d.Server.Filesystem.EnsureDataDirectory(); err != nil { return errors.WithStack(err) } // 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 := cli.ContainerInspect(ctx, d.Server.Uuid); err == nil { return nil } else if !client.IsErrNotFound(err) { return errors.WithStack(err) } // Try to pull the requested image before creating the container. if err := d.ensureImageExists(cli); err != nil { return errors.WithStack(err) } conf := &container.Config{ Hostname: "container", User: strconv.Itoa(config.Get().System.User.Uid), AttachStdin: true, AttachStdout: true, AttachStderr: true, OpenStdin: true, Tty: true, ExposedPorts: d.exposedPorts(), Image: d.Server.Container.Image, Env: d.environmentVariables(), Labels: map[string]string{ "Service": "Pterodactyl", "ContainerType": "server_process", }, } hostConf := &container.HostConfig{ PortBindings: d.portBindings(), // Configure the mounts for this container. First mount the server data directory // into the container as a r/w bind. Mounts: []mount.Mount{ { Target: "/home/container", Source: d.Server.Filesystem.Path(), Type: mount.TypeBind, ReadOnly: false, }, }, // 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=50M", }, // Define resource limits for the container based on the data passed through // from the Panel. Resources: d.getResourcesForServer(), 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: jsonfilelog.Name, Config: map[string]string{ "max-size": "5m", "max-file": "1", }, }, 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), } if _, err := cli.ContainerCreate(ctx, conf, hostConf, nil, d.Server.Uuid); err != nil { return errors.WithStack(err) } return nil } // 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 (d *DockerEnvironment) SendCommand(c string) error { if !d.attached { return errors.New("attempting to send command to non-attached instance") } _, err := d.stream.Conn.Write([]byte(c + "\n")) return errors.WithStack(err) } // 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 (d *DockerEnvironment) Readlog(len int64) ([]string, error) { ctx := context.Background() j, err := d.Client.ContainerInspect(ctx, d.Server.Uuid) if err != nil { return nil, err } if j.LogPath == "" { return nil, errors.New("empty log path defined for server") } f, err := os.Open(j.LogPath) if err != nil { return nil, err } defer f.Close() // Check if the length of the file is smaller than the amount of data that was requested // for reading. If so, adjust the length to be the total length of the file. If this is not // done an error is thrown since we're reading backwards, and not forwards. if stat, err := os.Stat(j.LogPath); err != nil { return nil, err } else if stat.Size() < len { len = stat.Size() } // Seed to the end of the file and then move backwards until the length is met to avoid // reading the entirety of the file into memory. if _, err := f.Seek(-len, io.SeekEnd); err != nil { return nil, err } b := make([]byte, len) if _, err := f.Read(b); err != nil && err != io.EOF { return nil, err } return d.parseLogToStrings(b) } type dockerLogLine struct { Log string `json:"log"` } // Docker stores the logs for server output in a JSON format. This function will iterate over the JSON // that was read from the log file and parse it into a more human readable format. func (d *DockerEnvironment) parseLogToStrings(b []byte) ([]string, error) { var hasError = false var out []string scanner := bufio.NewScanner(bytes.NewReader(b)) for scanner.Scan() { var l dockerLogLine // Unmarshal the contents and allow up to a single error before bailing out of the process. We // do this because if you're arbitrarily reading a length of the file you'll likely end up // with the first line in the output being improperly formatted JSON. In those cases we want to // just skip over it. However if we see another error we're going to bail out because that is an // abnormal situation. if err := json.Unmarshal([]byte(scanner.Text()), &l); err != nil { if hasError { return nil, err } hasError = true continue } out = append(out, l.Log) } return out, nil } // Returns the environment variables for a server in KEY="VALUE" form. func (d *DockerEnvironment) environmentVariables() []string { zone, _ := time.Now().In(time.Local).Zone() var out = []string{ fmt.Sprintf("TZ=%s", zone), fmt.Sprintf("STARTUP=%s", d.Server.Invocation), fmt.Sprintf("SERVER_MEMORY=%d", d.Server.Build.MemoryLimit), fmt.Sprintf("SERVER_IP=%s", d.Server.Allocations.DefaultMapping.Ip), fmt.Sprintf("SERVER_PORT=%d", d.Server.Allocations.DefaultMapping.Port), } eloop: for k, v := range d.Server.EnvVars { for _, e := range out { if strings.HasPrefix(e, strings.ToUpper(k)) { continue eloop } } out = append(out, fmt.Sprintf("%s=%s", strings.ToUpper(k), v)) } return out } func (d *DockerEnvironment) volumes() map[string]struct{} { return nil } // Converts the server allocation mappings into a format that can be understood // by Docker. func (d *DockerEnvironment) portBindings() nat.PortMap { var out = nat.PortMap{} for ip, ports := range d.Server.Allocations.Mappings { for _, port := range ports { // Skip over invalid ports. if port < 0 || port > 65535 { continue } binding := []nat.PortBinding{ { HostIP: ip, HostPort: strconv.Itoa(port), }, } out[nat.Port(fmt.Sprintf("%d/tcp", port))] = binding out[nat.Port(fmt.Sprintf("%d/udp", port))] = binding } } return out } // Converts the server allocation mappings into a PortSet that can be understood // by Docker. This formatting is slightly different than portBindings as it should // return an empty struct rather than a binding. // // To accomplish this, we'll just get the values from portBindings and then set them // to empty structs. Because why not. func (d *DockerEnvironment) exposedPorts() nat.PortSet { var out = nat.PortSet{} for port := range d.portBindings() { out[port] = struct{}{} } return out } // Formats the resources available to a server instance in such as way that Docker will // generate a matching environment in the container. // // This will set the actual memory limit on the container using the multiplier which is the // hard limit for the container (after which will result in a crash). We then set the // reservation to be the expected memory limit based on simply multiplication. // // The swap value is either -1 to disable it, or set to the value of the hard memory limit // plus the additional swap assigned to the server since Docker expects this value to be // the same or higher than the memory limit. func (d *DockerEnvironment) getResourcesForServer() container.Resources { return container.Resources{ Memory: d.Server.Build.BoundedMemoryLimit(), MemoryReservation: d.Server.Build.MemoryLimit * 1_000_000, MemorySwap: d.Server.Build.ConvertedSwap(), CPUQuota: d.Server.Build.ConvertedCpuLimit(), CPUPeriod: 100_000, CPUShares: 1024, BlkioWeight: d.Server.Build.IoWeight, OomKillDisable: &d.Server.Container.OomDisabled, CpusetCpus: d.Server.Build.Threads, } }