wings/server/environment_docker.go

1028 lines
31 KiB
Go

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"
"path/filepath"
"strconv"
"strings"
"sync"
"time"
)
// Defines the base environment for Docker instances running through Wings.
type DockerEnvironment struct {
sync.RWMutex
Server *Server
// The Docker client being used for this instance.
Client *client.Client
// 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
}
// Set if this process is currently attached to the process.
func (d *DockerEnvironment) SetStream(s *types.HijackedResponse) {
d.Lock()
d.stream = s
d.Unlock()
}
// Determine if the this process is currently attached to the container.
func (d *DockerEnvironment) IsAttached() bool {
d.RLock()
defer d.RUnlock()
return d.stream != nil
}
// 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.Id())
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) {
c, err := d.Client.ContainerInspect(context.Background(), d.Server.Id())
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.Id()); 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)
}
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")
ctx, cancel := context.WithTimeout(context.Background(), time.Second*10)
defer cancel()
if _, err := d.Client.ContainerUpdate(ctx, d.Server.Id(), 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.Id(), 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.IsSuspended() {
return &suspendedError{}
}
if c, err := d.Client.ContainerInspect(context.Background(), d.Server.Id()); 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, cancel := context.WithTimeout(context.Background(), time.Second*10)
defer cancel()
if err := d.Client.ContainerStart(ctx, d.Server.Id(), 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)
// Only attempt to send the stop command to the instance if we are actually attached to
// the instance. If we are not for some reason, just send the container stop event.
if d.IsAttached() && stop.Type == api.ProcessStopCommand {
return d.SendCommand(stop.Value)
}
t := time.Second * 10
err := d.Client.ContainerStop(context.Background(), d.Server.Id(), &t)
if err != nil {
// If the container does not exist just mark the process as stopped and return without
// an error.
if client.IsErrNotFound(err) {
d.SetStream(nil)
d.Server.SetState(ProcessOfflineState)
return nil
}
return err
}
return nil
}
// Restarts the server process by waiting for the process to gracefully stop and then triggering a
// start command. This will return an error if there is already a restart process executing for the
// server. The lock is released when the process is stopped and a start has begun.
func (d *DockerEnvironment) Restart() error {
err := d.WaitForStop(60, false)
if err != nil {
return err
}
// Start the process.
return d.Start()
}
// 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.Id(), 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 {
c, err := d.Client.ContainerInspect(context.Background(), d.Server.Id())
if err != nil {
return errors.WithStack(err)
}
if !c.State.Running {
return nil
}
d.Server.SetState(ProcessStoppingState)
return d.Client.ContainerKill(
context.Background(), d.Server.Id(), 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 {
// Avoid crash detection firing off.
d.Server.SetState(ProcessStoppingState)
err := d.Client.ContainerRemove(context.Background(), d.Server.Id(), 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.Id())
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 that's 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.IsAttached() {
return nil
}
if err := d.FollowConsoleOutput(); err != nil {
return errors.WithStack(err)
}
opts := types.ContainerAttachOptions{
Stdin: true,
Stdout: true,
Stderr: true,
Stream: true,
}
// Set the stream again with the container.
if st, err := d.Client.ContainerAttach(context.Background(), d.Server.Id(), opts); err != nil {
return errors.WithStack(err)
} else {
d.SetStream(&st)
}
console := Console{
Server: d.Server,
}
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.SetStream(nil)
}()
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.Id()))
}
opts := types.ContainerLogsOptions{
ShowStderr: true,
ShowStdout: true,
Follow: true,
Since: time.Now().Format(time.RFC3339),
}
reader, err := d.Client.ContainerLogs(context.Background(), d.Server.Id(), 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")
}
stats, err := d.Client.ContainerStats(context.Background(), d.Server.Id(), 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.Proc().UpdateFromDocker(v)
for _, nw := range v.Networks {
s.Proc().UpdateNetworkBytes(&nw)
}
// 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()
b, _ := json.Marshal(s.Proc())
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.Proc().Empty()
return errors.WithStack(err)
}
// Returns the image to be used for the instance.
func (d *DockerEnvironment) Image() string {
return d.Server.Config().Container.Image
}
// 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() 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, cancel := context.WithTimeout(context.Background(), time.Minute*15)
defer cancel()
image := d.Image()
// 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 repository")
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 := d.Client.ImagePull(ctx, image, imagePullOptions)
if err != nil {
images, ierr := d.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 ierr
}
for _, img := range images {
for _, t := range img.RepoTags {
if t != d.Image() {
continue
}
d.Server.Log().WithFields(log.Fields{
"image": d.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.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 {
// 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 := d.Client.ContainerInspect(context.Background(), d.Server.Id()); 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(); err != nil {
return errors.WithStack(err)
}
conf := &container.Config{
Hostname: d.Server.Id(),
Domainname: config.Get().Docker.Domainname,
User: strconv.Itoa(config.Get().System.User.Uid),
AttachStdin: true,
AttachStdout: true,
AttachStderr: true,
OpenStdin: true,
Tty: true,
ExposedPorts: d.exposedPorts(),
Image: d.Image(),
Env: d.Server.GetEnvironmentVariables(),
Labels: map[string]string{
"Service": "Pterodactyl",
"ContainerType": "server_process",
},
}
mounts, err := d.getContainerMounts()
if err != nil {
return errors.WithMessage(err, "could not build container mount points slice")
}
customMounts, err := d.getCustomMounts()
if err != nil {
return errors.WithMessage(err, "could not build custom container mount points slice")
}
if len(customMounts) > 0 {
mounts = append(mounts, customMounts...)
for _, m := range customMounts {
d.Server.Log().WithFields(log.Fields{
"source_path": m.Source,
"target_path": m.Target,
"read_only": m.ReadOnly,
}).Debug("attaching custom server mount point to container")
}
}
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: mounts,
// 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 := d.Client.ContainerCreate(context.Background(), conf, hostConf, nil, d.Server.Id()); err != nil {
return errors.WithStack(err)
}
return nil
}
// Returns the default container mounts for the server instance. This includes the data directory
// for the server as well as any timezone related files if they exist on the host system so that
// servers running within the container will use the correct time.
func (d *DockerEnvironment) getContainerMounts() ([]mount.Mount, error) {
var m []mount.Mount
m = append(m, mount.Mount{
Target: "/home/container",
Source: d.Server.Filesystem.Path(),
Type: mount.TypeBind,
ReadOnly: false,
})
// Try to mount in /etc/localtime and /etc/timezone if they exist on the host system.
if _, err := os.Stat("/etc/localtime"); err != nil {
if !os.IsNotExist(err) {
return nil, err
}
} else {
m = append(m, mount.Mount{
Target: "/etc/localtime",
Source: "/etc/localtime",
Type: mount.TypeBind,
ReadOnly: true,
})
}
if _, err := os.Stat("/etc/timezone"); err != nil {
if !os.IsNotExist(err) {
return nil, err
}
} else {
m = append(m, mount.Mount{
Target: "/etc/timezone",
Source: "/etc/timezone",
Type: mount.TypeBind,
ReadOnly: true,
})
}
return m, nil
}
// Returns the custom mounts for a given server after verifying that they are within a list of
// allowed mount points for the node.
func (d *DockerEnvironment) getCustomMounts() ([]mount.Mount, error) {
var mounts []mount.Mount
// TODO: probably need to handle things trying to mount directories that do not exist.
for _, m := range d.Server.Config().Mounts {
source := filepath.Clean(m.Source)
target := filepath.Clean(m.Target)
logger := d.Server.Log().WithFields(log.Fields{
"source_path": source,
"target_path": target,
"read_only": m.ReadOnly,
})
mounted := false
for _, allowed := range config.Get().AllowedMounts {
if !strings.HasPrefix(source, allowed) {
continue
}
mounted = true
mounts = append(mounts, mount.Mount{
Source: source,
Target: target,
Type: mount.TypeBind,
ReadOnly: m.ReadOnly,
})
break
}
if !mounted {
logger.Warn("skipping custom server mount, not in list of allowed mount points")
}
}
return mounts, 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 {
d.RLock()
defer d.RUnlock()
if !d.IsAttached() {
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) {
j, err := d.Client.ContainerInspect(context.Background(), d.Server.Id())
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
}
// 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.Config().Allocations.Mappings {
for _, port := range ports {
// Skip over invalid ports.
if port < 1 || 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.Config().Container.OomDisabled,
CpusetCpus: d.Server.Build().Threads,
}
}