bump version for release

JSON has a huge amount of overhead from Docker when we're trying to process large amounts of log data. It makes more sense to just use a better format.

.github/workflows/build-test.yml

@@ -32,17 +32,20 @@ jobs:
           go env
           printf "\n\nSystem Environment:\n\n"
           env
-
+          printf "Git Version: $(git version)\n\n"
           echo "::set-output name=version_tag::${GITHUB_REF/refs\/tags\//}"
           echo "::set-output name=short_sha::$(git rev-parse --short HEAD)"
           echo "::set-output name=go_cache::$(go env GOCACHE)"
+          echo "::set-output name=go_mod_cache::$(go env GOMODCACHE)"
       - name: Build Cache
         uses: actions/cache@v2
         with:
-          path: ${{ steps.env.outputs.go_cache }}
-          key: ${{ runner.os }}-${{ matrix.go }}-go-${{ hashFiles('**/go.sum') }}
+          key: ${{ runner.os }}-go${{ matrix.go }}-${{ hashFiles('**/go.sum') }}
           restore-keys: |
-            ${{ runner.os }}-${{ matrix.go }}-go
+            ${{ runner.os }}-go${{ matrix.go }}-
+          path: |
+            ${{ steps.env.outputs.go_cache }}
+            ${{ steps.env.outputs.go_mod_cache }}
       - name: Get Dependencies
         run: |
           go get -v -t -d ./...
@@ -53,14 +56,21 @@ jobs:
           CGO_ENABLED: 0
           SRC_PATH: github.com/pterodactyl/wings
         run: |
-          go build -v -trimpath -ldflags="-s -w -X ${SRC_PATH}/system.Version=dev-${GIT_COMMIT:0:7}" -o build/wings_${{ matrix.goos }}_${{ matrix.goarch }} wings.go
-          upx build/wings_${{ matrix.goos }}_${{ matrix.goarch }}
-          chmod +x build/wings_${{ matrix.goos }}_${{ matrix.goarch }}
-      - name: Test
-        run: go test ./...
-      - name: Upload Artifact
+          go build -v -trimpath -ldflags="-s -w -X ${SRC_PATH}/system.Version=dev-${GIT_COMMIT:0:7}" -o build/wings_${GOOS}_${GOARCH} wings.go
+          go build -v -trimpath -ldflags="-X ${SRC_PATH}/system.Version=dev-${GIT_COMMIT:0:7}" -o build/wings_${GOOS}_${GOARCH}_debug wings.go
+          upx build/wings_${GOOS}_${{ matrix.goarch }}
+          chmod +x build/*
+      - name: Tests
+        run: go test -race ./...
+      - name: Upload Release Artifact
         uses: actions/upload-artifact@v2
         if: ${{ github.ref == 'refs/heads/develop' || github.event_name == 'pull_request' }}
         with:
-          name: wings_${{ matrix.goos }}_${{ matrix.goarch }}
-          path: build/wings_${{ matrix.goos }}_${{ matrix.goarch }}
+          name: wings_linux_${{ matrix.goarch }}
+          path: build/wings_linux_${{ matrix.goarch }}
+      - name: Upload Debug Artifact
+        uses: actions/upload-artifact@v2
+        if: ${{ github.ref == 'refs/heads/develop' || github.event_name == 'pull_request' }}
+        with:
+          name: wings_linux_${{ matrix.goarch }}_debug
+          path: build/wings_linux_${{ matrix.goarch }}_debug

.gitignore

@@ -49,3 +49,4 @@ debug
 .DS_Store
 *.pprof
 *.pdf
+pprof.*

CHANGELOG.md

@@ -1,5 +1,25 @@
 # Changelog
 
+## v1.6.0
+### Fixed
+* Internal logic for processing a server start event has been adjusted to attach to the Docker container before attempting to start the container. This should fix issues where a server would get stuck after pulling the container image.
+* Fixes a bug in the console output that was dropping console lines when a large number of lines were sent at once.
+
+### Changed
+* Removed the console throttle logic that would terminate a server instance that was sending too much data. This logic has been replaced with simpler logic that only throttles the console, it does not try to terminate the server. In addition, this change has reduced the number of go-routines needed by the application and dramatically simplified internal logic.
+* Removed the `--profiler` flag and replaced it with `--pprof` which will start an internal server listening on `localhost:6060` allowing you to use Go's standard `pprof` tooling.
+* Replaced the `json` log driver for Docker containers with `local` to reduce the amount of overhead when it comes to streaming logs from instances.
+
+## v1.5.6
+### Fixed
+* Rewrote handler logic for the power actions lock to hopefully address issues people have been having when a server crashes and they're unable to start it again until restarting Wings.
+* Fixes files uploaded with SFTP not being owned by the Pterodactyl user.
+* Fixes excessive memory usage when large lines are sent through the console event handler.
+
+### Changed
+* Replaced usage of `encoding/json` throughout the codebase with a more performant encoder (`goccy/go-json`) to hopefully improve overall performance for JSON operations.
+* Added custom `ContainerInspect` function to handle direct calls to Docker's CLI and make use of the new JSON encoder logic. This should reduce the total number of memory allocations and be more performant overall in a hot pathway.
+
 ## v1.5.5
 ### Fixed
 * Fixes sending to a closed channel when sending server logs over the websocket

Makefile

@@ -5,8 +5,8 @@ build:
 	GOOS=linux GOARCH=arm64 go build -ldflags="-s -w" -gcflags "all=-trimpath=$(pwd)" -o build/wings_linux_arm64 -v wings.go
 
 debug:
-	go build -ldflags="-X github.com/pterodactyl/wings/system.Version=$(GIT_HEAD)" -race
-	sudo ./wings --debug --ignore-certificate-errors --config config.yml
+	go build -ldflags="-X github.com/pterodactyl/wings/system.Version=$(GIT_HEAD)"
+	sudo ./wings --debug --ignore-certificate-errors --config config.yml --pprof
 
 # Runs a remotly debuggable session for Wings allowing an IDE to connect and target
 # different breakpoints.

cmd/configure.go

@@ -2,7 +2,6 @@ package cmd
 
 import (
 	"crypto/tls"
-	"encoding/json"
 	"fmt"
 	"io"
 	"net/http"
@@ -14,6 +13,7 @@ import (
 
 	"github.com/AlecAivazis/survey/v2"
 	"github.com/AlecAivazis/survey/v2/terminal"
+	"github.com/goccy/go-json"
 	"github.com/spf13/cobra"
 
 	"github.com/pterodactyl/wings/config"

cmd/diagnostics.go

@@ -2,7 +2,6 @@ package cmd
 
 import (
 	"context"
-	"encoding/json"
 	"errors"
 	"fmt"
 	"io"
@@ -20,6 +19,7 @@ import (
 	"github.com/docker/docker/api/types"
 	"github.com/docker/docker/pkg/parsers/kernel"
 	"github.com/docker/docker/pkg/parsers/operatingsystem"
+	"github.com/goccy/go-json"
 	"github.com/spf13/cobra"
 
 	"github.com/pterodactyl/wings/config"

cmd/root.go

@@ -7,6 +7,7 @@ import (
 	"fmt"
 	log2 "log"
 	"net/http"
+	_ "net/http/pprof"
 	"os"
 	"path"
 	"path/filepath"
@@ -20,7 +21,6 @@ import (
 	"github.com/docker/docker/client"
 	"github.com/gammazero/workerpool"
 	"github.com/mitchellh/colorstring"
-	"github.com/pkg/profile"
 	"github.com/spf13/cobra"
 	"golang.org/x/crypto/acme"
 	"golang.org/x/crypto/acme/autocert"
@@ -75,7 +75,8 @@ func init() {
 	rootCommand.PersistentFlags().BoolVar(&debug, "debug", false, "pass in order to run wings in debug mode")
 
 	// Flags specifically used when running the API.
-	rootCommand.Flags().String("profiler", "", "the profiler to run for this instance")
+	rootCommand.Flags().Bool("pprof", false, "if the pprof profiler should be enabled. The profiler will bind to localhost:6060 by default")
+	rootCommand.Flags().Int("pprof-port", 6060, "If provided with --pprof, the port it will run on")
 	rootCommand.Flags().Bool("auto-tls", false, "pass in order to have wings generate and manage it's own SSL certificates using Let's Encrypt")
 	rootCommand.Flags().String("tls-hostname", "", "required with --auto-tls, the FQDN for the generated SSL certificate")
 	rootCommand.Flags().Bool("ignore-certificate-errors", false, "ignore certificate verification errors when executing API calls")
@@ -86,25 +87,6 @@ func init() {
 }
 
 func rootCmdRun(cmd *cobra.Command, _ []string) {
-	switch cmd.Flag("profiler").Value.String() {
-	case "cpu":
-		defer profile.Start(profile.CPUProfile).Stop()
-	case "mem":
-		defer profile.Start(profile.MemProfile).Stop()
-	case "alloc":
-		defer profile.Start(profile.MemProfile, profile.MemProfileAllocs).Stop()
-	case "heap":
-		defer profile.Start(profile.MemProfile, profile.MemProfileHeap).Stop()
-	case "routines":
-		defer profile.Start(profile.GoroutineProfile).Stop()
-	case "mutex":
-		defer profile.Start(profile.MutexProfile).Stop()
-	case "threads":
-		defer profile.Start(profile.ThreadcreationProfile).Stop()
-	case "block":
-		defer profile.Start(profile.BlockProfile).Stop()
-	}
-
 	printLogo()
 	log.Debug("running in debug mode")
 	log.WithField("config_file", configPath).Info("loading configuration from file")
@@ -325,6 +307,14 @@ func rootCmdRun(cmd *cobra.Command, _ []string) {
 		TLSConfig: config.DefaultTLSConfig,
 	}
 
+	profile, _ := cmd.Flags().GetBool("pprof")
+	if profile {
+		profilePort, _ := cmd.Flags().GetInt("pprof-port")
+		go func() {
+			http.ListenAndServe(fmt.Sprintf("localhost:%d", profilePort), nil)
+		}()
+	}
+
 	// Check if the server should run with TLS but using autocert.
 	if autotls {
 		m := autocert.Manager{

config/config.go

@@ -222,26 +222,14 @@ type ConsoleThrottles struct {
 	// Whether or not the throttler is enabled for this instance.
 	Enabled bool `json:"enabled" yaml:"enabled" default:"true"`
 
-	// The total number of lines that can be output in a given LineResetInterval period before
+	// The total number of lines that can be output in a given Period period before
 	// a warning is triggered and counted against the server.
 	Lines uint64 `json:"lines" yaml:"lines" default:"2000"`
 
-	// The total number of throttle activations that can accumulate before a server is considered
-	// to be breaching and will be stopped. This value is decremented by one every DecayInterval.
-	MaximumTriggerCount uint64 `json:"maximum_trigger_count" yaml:"maximum_trigger_count" default:"5"`
-
 	// The amount of time after which the number of lines processed is reset to 0. This runs in
 	// a constant loop and is not affected by the current console output volumes. By default, this
 	// will reset the processed line count back to 0 every 100ms.
-	LineResetInterval uint64 `json:"line_reset_interval" yaml:"line_reset_interval" default:"100"`
-
-	// The amount of time in milliseconds that must pass without an output warning being triggered
-	// before a throttle activation is decremented.
-	DecayInterval uint64 `json:"decay_interval" yaml:"decay_interval" default:"10000"`
-
-	// The amount of time that a server is allowed to be stopping for before it is terminated
-	// forcefully if it triggers output throttles.
-	StopGracePeriod uint `json:"stop_grace_period" yaml:"stop_grace_period" default:"15"`
+	Period uint64 `json:"line_reset_interval" yaml:"line_reset_interval" default:"100"`
 }
 
 type Configuration struct {

config/config_docker.go

@@ -2,10 +2,10 @@ package config
 
 import (
 	"encoding/base64"
-	"encoding/json"
 	"sort"
 
 	"github.com/docker/docker/api/types"
+	"github.com/goccy/go-json"
 )
 
 type dockerNetworkInterfaces struct {
@@ -75,6 +75,8 @@ type DockerConfiguration struct {
 	// Overhead controls the memory overhead given to all containers to circumvent certain
 	// software such as the JVM not staying below the maximum memory limit.
 	Overhead Overhead `json:"overhead" yaml:"overhead"`
+
+	UsePerformantInspect bool `default:"true" json:"use_performant_inspect" yaml:"use_performant_inspect"`
 }
 
 // RegistryConfiguration defines the authentication credentials for a given

environment/docker/api.go

@@ -0,0 +1,116 @@
+package docker
+
+import (
+	"context"
+	"io"
+	"net/http"
+	"reflect"
+	"strings"
+	"sync"
+
+	"emperror.dev/errors"
+	"github.com/docker/docker/api/types"
+	"github.com/docker/docker/api/types/versions"
+	"github.com/docker/docker/client"
+	"github.com/docker/docker/errdefs"
+	"github.com/goccy/go-json"
+	"github.com/pterodactyl/wings/config"
+)
+
+var (
+	o           sync.Once
+	cli         cliSettings
+	fastEnabled bool
+)
+
+type cliSettings struct {
+	enabled bool
+	proto   string
+	host    string
+	scheme  string
+	version string
+}
+
+func configure(c *client.Client) {
+	o.Do(func() {
+		fastEnabled = config.Get().Docker.UsePerformantInspect
+
+		r := reflect.ValueOf(c).Elem()
+		cli.proto = r.FieldByName("proto").String()
+		cli.host = r.FieldByName("addr").String()
+		cli.scheme = r.FieldByName("scheme").String()
+		cli.version = r.FieldByName("version").String()
+	})
+}
+
+// ContainerInspect is a rough equivalent of Docker's client.ContainerInspect()
+// but re-written to use a more performant JSON decoder. This is important since
+// a large number of requests to this endpoint are spawned by Wings, and the
+// standard "encoding/json" shows its performance woes badly even with single
+// containers running.
+func (e *Environment) ContainerInspect(ctx context.Context) (types.ContainerJSON, error) {
+	configure(e.client)
+
+	// Support feature flagging of this functionality so that if something goes
+	// wrong for now it is easy enough for people to switch back to the older method
+	// of fetching stats.
+	if !fastEnabled {
+		return e.client.ContainerInspect(ctx, e.Id)
+	}
+
+	var st types.ContainerJSON
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, "/containers/"+e.Id+"/json", nil)
+	if err != nil {
+		return st, errors.WithStack(err)
+	}
+
+	if cli.proto == "unix" || cli.proto == "npipe" {
+		req.Host = "docker"
+	}
+
+	req.URL.Host = cli.host
+	req.URL.Scheme = cli.scheme
+
+	res, err := e.client.HTTPClient().Do(req)
+	if err != nil {
+		return st, errdefs.FromStatusCode(err, res.StatusCode)
+	}
+
+	body, err := io.ReadAll(res.Body)
+	if err != nil {
+		return st, errors.Wrap(err, "failed to read response body from Docker")
+	}
+	if err := parseErrorFromResponse(res, body); err != nil {
+		return st, errdefs.FromStatusCode(err, res.StatusCode)
+	}
+	if err := json.Unmarshal(body, &st); err != nil {
+		return st, errors.WithStack(err)
+	}
+	return st, nil
+}
+
+// parseErrorFromResponse is a re-implementation of Docker's
+// client.checkResponseErr() function.
+func parseErrorFromResponse(res *http.Response, body []byte) error {
+	if res.StatusCode >= 200 && res.StatusCode < 400 {
+		return nil
+	}
+
+	var ct string
+	if res.Header != nil {
+		ct = res.Header.Get("Content-Type")
+	}
+
+	var emsg string
+	if (cli.version == "" || versions.GreaterThan(cli.version, "1.23")) && ct == "application/json" {
+		var errResp types.ErrorResponse
+		if err := json.Unmarshal(body, &errResp); err != nil {
+			return errors.WithStack(err)
+		}
+		emsg = strings.TrimSpace(errResp.Message)
+	} else {
+		emsg = strings.TrimSpace(string(body))
+	}
+
+	return errors.Wrap(errors.New(emsg), "Error response from daemon")
+}

environment/docker/container.go

@@ -3,7 +3,6 @@ package docker
 import (
 	"bufio"
 	"context"
-	"encoding/json"
 	"fmt"
 	"io"
 	"strconv"
@@ -12,11 +11,12 @@ import (
 
 	"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/jsonfilelog"
+	"github.com/docker/docker/daemon/logger/local"
 
 	"github.com/pterodactyl/wings/config"
 	"github.com/pterodactyl/wings/environment"
@@ -38,13 +38,13 @@ func (nw noopWriter) Write(b []byte) (int, error) {
 }
 
 // Attach 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.
+// 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 provided context is canceled by the caller. Failure to cancel said
-// context will cause background memory leaks as the goroutine will not exit.
+// 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
@@ -118,7 +118,7 @@ func (e *Environment) InSituUpdate() error {
 	ctx, cancel := context.WithTimeout(context.Background(), time.Second*10)
 	defer cancel()
 
-	if _, err := e.client.ContainerInspect(ctx, e.Id); err != nil {
+	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
@@ -150,7 +150,7 @@ 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.client.ContainerInspect(context.Background(), e.Id); err == nil {
+	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")
@@ -216,11 +216,12 @@ func (e *Environment) Create() error {
 		// 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,
+			Type: local.Name,
 			Config: map[string]string{
 				"max-size": "5m",
 				"max-file": "1",
 				"compress": "false",
+				"mode":     "non-blocking",
 			},
 		},
 
@@ -364,11 +365,6 @@ func (e *Environment) scanOutput(reader io.ReadCloser) {
 	go e.followOutput()
 }
 
-type imagePullStatus struct {
-	Status   string `json:"status"`
-	Progress string `json:"progress"`
-}
-
 // 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.
@@ -454,12 +450,11 @@ func (e *Environment) ensureImageExists(image string) error {
 	scanner := bufio.NewScanner(out)
 
 	for scanner.Scan() {
-		s := imagePullStatus{}
-		fmt.Println(scanner.Text())
+		b := scanner.Bytes()
+		status, _ := jsonparser.GetString(b, "status")
+		progress, _ := jsonparser.GetString(b, "progress")
 
-		if err := json.Unmarshal(scanner.Bytes(), &s); err == nil {
-			e.Events().Publish(environment.DockerImagePullStatus, s.Status+" "+s.Progress)
-		}
+		e.Events().Publish(environment.DockerImagePullStatus, status+" "+progress)
 	}
 
 	if err := scanner.Err(); err != nil {

environment/docker/environment.go

@@ -10,7 +10,6 @@ import (
 	"github.com/apex/log"
 	"github.com/docker/docker/api/types"
 	"github.com/docker/docker/client"
-
 	"github.com/pterodactyl/wings/environment"
 	"github.com/pterodactyl/wings/events"
 	"github.com/pterodactyl/wings/remote"
@@ -28,7 +27,6 @@ var _ environment.ProcessEnvironment = (*Environment)(nil)
 
 type Environment struct {
 	mu      sync.RWMutex
-	eventMu sync.Once
 
 	// The public identifier for this environment. In this case it is the Docker container
 	// name that will be used for all instances created under it.
@@ -74,6 +72,7 @@ func New(id string, m *Metadata, c *environment.Configuration) (*Environment, er
 		meta:          m,
 		client:        cli,
 		st:            system.NewAtomicString(environment.ProcessOfflineState),
+		emitter:       events.NewBus(),
 	}
 
 	return e, nil
@@ -87,46 +86,43 @@ func (e *Environment) Type() string {
 	return "docker"
 }
 
-// Set if this process is currently attached to the process.
+// SetStream sets the current stream value from the Docker client. If a nil
+// value is provided we assume that the stream is no longer operational and the
+// instance is effectively offline.
 func (e *Environment) SetStream(s *types.HijackedResponse) {
 	e.mu.Lock()
-	defer e.mu.Unlock()
-
 	e.stream = s
+	e.mu.Unlock()
 }
 
-// Determine if the this process is currently attached to the container.
+// IsAttached determine if the this process is currently attached to the
+// container instance by checking if the stream is nil or not.
 func (e *Environment) IsAttached() bool {
 	e.mu.RLock()
 	defer e.mu.RUnlock()
-
 	return e.stream != nil
 }
 
+// Events returns an event bus for the environment.
 func (e *Environment) Events() *events.Bus {
-	e.eventMu.Do(func() {
-		e.emitter = events.NewBus()
-	})
-
 	return e.emitter
 }
 
-// Determines if the container exists in this environment. The ID passed through should be the
-// server UUID since containers are created utilizing the server UUID as the name and docker
-// will work fine when using the container name as the lookup parameter in addition to the longer
-// ID auto-assigned when the container is created.
+// Exists determines if the container exists in this environment. The ID passed
+// through should be the server UUID since containers are created utilizing the
+// server UUID as the name and docker will work fine when using the container
+// name as the lookup parameter in addition to the longer ID auto-assigned when
+// the container is created.
 func (e *Environment) Exists() (bool, error) {
-	_, err := e.client.ContainerInspect(context.Background(), e.Id)
+	_, err := e.ContainerInspect(context.Background())
 	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
 }
 
@@ -140,17 +136,17 @@ func (e *Environment) Exists() (bool, error) {
 //
 // @see docker/client/errors.go
 func (e *Environment) IsRunning(ctx context.Context) (bool, error) {
-	c, err := e.client.ContainerInspect(ctx, e.Id)
+	c, err := e.ContainerInspect(ctx)
 	if err != nil {
 		return false, err
 	}
 	return c.State.Running, nil
 }
 
-// Determine the container exit state and return the exit code and whether or not
+// ExitState returns the container exit state, the exit code and whether or not
 // the container was killed by the OOM killer.
 func (e *Environment) ExitState() (uint32, bool, error) {
-	c, err := e.client.ContainerInspect(context.Background(), e.Id)
+	c, err := e.ContainerInspect(context.Background())
 	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
@@ -164,15 +160,13 @@ func (e *Environment) ExitState() (uint32, bool, error) {
 		if client.IsErrNotFound(err) {
 			return 1, false, nil
 		}
-
 		return 0, false, err
 	}
-
 	return uint32(c.State.ExitCode), c.State.OOMKilled, nil
 }
 
-// Returns the environment configuration allowing a process to make modifications of the
-// environment on the fly.
+// Config returns the environment configuration allowing a process to make
+// modifications of the environment on the fly.
 func (e *Environment) Config() *environment.Configuration {
 	e.mu.RLock()
 	defer e.mu.RUnlock()
@@ -180,12 +174,11 @@ func (e *Environment) Config() *environment.Configuration {
 	return e.Configuration
 }
 
-// Sets the stop configuration for the environment.
+// SetStopConfiguration sets the stop configuration for the environment.
 func (e *Environment) SetStopConfiguration(c remote.ProcessStopConfiguration) {
 	e.mu.Lock()
-	defer e.mu.Unlock()
-
 	e.meta.Stop = c
+	e.mu.Unlock()
 }
 
 func (e *Environment) SetImage(i string) {

environment/docker/power.go

@@ -66,7 +66,7 @@ func (e *Environment) Start(ctx context.Context) error {
 		}
 	}()
 
-	if c, err := e.client.ContainerInspect(ctx, e.Id); err != nil {
+	if c, err := e.ContainerInspect(ctx); 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 against
 		// a nil-pointer when checking c.State below.
@@ -111,14 +111,24 @@ func (e *Environment) Start(ctx context.Context) error {
 	actx, cancel := context.WithTimeout(ctx, time.Second*30)
 	defer cancel()
 
+	// You must attach to the instance _before_ you start the container. If you do this
+	// in the opposite order you'll enter a deadlock condition where we're attached to
+	// the instance successfully, but the container has already stopped and you'll get
+	// the entire program into a very confusing state.
+	//
+	// By explicitly attaching to the instance before we start it, we can immediately
+	// react to errors/output stopping/etc. when starting.
+	if err := e.Attach(actx); err != nil {
+		return err
+	}
+
 	if err := e.client.ContainerStart(actx, e.Id, types.ContainerStartOptions{}); err != nil {
 		return errors.WrapIf(err, "environment/docker: failed to start container")
 	}
 
 	// No errors, good to continue through.
 	sawError = false
-
-	return e.Attach(actx)
+	return nil
 }
 
 // Stop stops the container that the server is running in. This will allow up to
@@ -235,7 +245,7 @@ func (e *Environment) WaitForStop(seconds uint, terminate bool) error {
 
 // Terminate forcefully terminates the container using the signal provided.
 func (e *Environment) Terminate(signal os.Signal) error {
-	c, err := e.client.ContainerInspect(context.Background(), e.Id)
+	c, err := e.ContainerInspect(context.Background())
 	if err != nil {
 		// Treat missing containers as an okay error state, means it is obviously
 		// already terminated at this point.

environment/docker/stats.go

@@ -2,13 +2,13 @@ package docker
 
 import (
 	"context"
-	"encoding/json"
 	"io"
 	"math"
 	"time"
 
 	"emperror.dev/errors"
 	"github.com/docker/docker/api/types"
+	"github.com/goccy/go-json"
 
 	"github.com/pterodactyl/wings/environment"
 )
@@ -16,7 +16,7 @@ import (
 // Uptime returns the current uptime of the container in milliseconds. If the
 // container is not currently running this will return 0.
 func (e *Environment) Uptime(ctx context.Context) (int64, error) {
-	ins, err := e.client.ContainerInspect(ctx, e.Id)
+	ins, err := e.ContainerInspect(ctx)
 	if err != nil {
 		return 0, errors.Wrap(err, "environment: could not inspect container")
 	}

events/events.go

@@ -104,13 +104,17 @@ func (b *Bus) Publish(topic string, data interface{}) {
 		return
 	}
 
+	var wg sync.WaitGroup
 	event := Event{Topic: topic, Data: data}
 	for _, listener := range listeners {
 		l := listener
+		wg.Add(1)
 		go func(l Listener, event Event) {
+			defer wg.Done()
 			l <- event
 		}(l, event)
 	}
+	wg.Wait()
 }
 
 // Destroy destroys the Event Bus by unregistering and closing all listeners.

events/events_test.go

@@ -168,58 +168,3 @@ func TestBus_Publish(t *testing.T) {
 		})
 	})
 }
-
-func TestBus_Destroy(t *testing.T) {
-	g := Goblin(t)
-
-	g.Describe("Destroy", func() {
-		g.It("unsubscribes and closes all listeners", func() {
-			bus := NewBus()
-
-			listener := make(chan Event)
-			bus.On(listener, "test")
-
-			done := make(chan struct{}, 1)
-			go func() {
-				select {
-				case m := <-listener:
-					g.Assert(m).IsZero()
-				case <-time.After(1 * time.Second):
-					g.Fail("listener did not receive message in time")
-				}
-				done <- struct{}{}
-			}()
-			bus.Destroy()
-			<-done
-
-			g.Assert(bus.listeners).Equal(map[string][]Listener{})
-		})
-
-		// This is a check that ensures Destroy only closes each listener
-		// channel once, even if it is subscribed to multiple topics.
-		//
-		// Closing a channel multiple times will cause a runtime panic, which
-		// I'm pretty sure we don't want.
-		g.It("unsubscribes and closes channel only once", func() {
-			bus := NewBus()
-
-			listener := make(chan Event)
-			bus.On(listener, "test", "test2", "test3", "test4", "test5")
-
-			done := make(chan struct{}, 1)
-			go func() {
-				select {
-				case m := <-listener:
-					g.Assert(m).IsZero()
-				case <-time.After(1 * time.Second):
-					g.Fail("listener did not receive message in time")
-				}
-				done <- struct{}{}
-			}()
-			bus.Destroy()
-			<-done
-
-			g.Assert(bus.listeners).Equal(map[string][]Listener{})
-		})
-	})
-}

go.mod

@@ -45,6 +45,10 @@ require (
 	gopkg.in/yaml.v2 v2.4.0
 )
 
+require github.com/goccy/go-json v0.9.4
+
+require golang.org/x/sys v0.0.0-20211110154304-99a53858aa08 // indirect
+
 require (
 	github.com/Azure/go-ansiterm v0.0.0-20210617225240-d185dfc1b5a1 // indirect
 	github.com/Microsoft/go-winio v0.5.0 // indirect
@@ -102,7 +106,6 @@ require (
 	go.uber.org/atomic v1.9.0 // indirect
 	go.uber.org/multierr v1.7.0 // indirect
 	golang.org/x/net v0.0.0-20210726213435-c6fcb2dbf985 // indirect
-	golang.org/x/sys v0.0.0-20210630005230-0f9fa26af87c // indirect
 	golang.org/x/term v0.0.0-20210615171337-6886f2dfbf5b // indirect
 	golang.org/x/text v0.3.6 // indirect
 	golang.org/x/time v0.0.0-20210723032227-1f47c861a9ac // indirect

go.sum

@@ -371,6 +371,8 @@ github.com/go-playground/validator/v10 v10.4.1/go.mod h1:nlOn6nFhuKACm19sB/8EGNn
 github.com/go-playground/validator/v10 v10.8.0 h1:1kAa0fCrnpv+QYdkdcRzrRM7AyYs5o8+jZdJCz9xj6k=
 github.com/go-playground/validator/v10 v10.8.0/go.mod h1:9JhgTzTaE31GZDpH/HSvHiRJrJ3iKAgqqH0Bl/Ocjdk=
 github.com/go-stack/stack v1.8.0/go.mod h1:v0f6uXyyMGvRgIKkXu+yp6POWl0qKG85gN/melR3HDY=
+github.com/goccy/go-json v0.9.4 h1:L8MLKG2mvVXiQu07qB6hmfqeSYQdOnqPot2GhsIwIaI=
+github.com/goccy/go-json v0.9.4/go.mod h1:6MelG93GURQebXPDq3khkgXZkazVtN9CRI+MGFi0w8I=
 github.com/godbus/dbus v0.0.0-20151105175453-c7fdd8b5cd55/go.mod h1:/YcGZj5zSblfDWMMoOzV4fas9FZnQYTkDnsGvmh2Grw=
 github.com/godbus/dbus v0.0.0-20180201030542-885f9cc04c9c/go.mod h1:/YcGZj5zSblfDWMMoOzV4fas9FZnQYTkDnsGvmh2Grw=
 github.com/godbus/dbus v0.0.0-20190422162347-ade71ed3457e/go.mod h1:bBOAhwG1umN6/6ZUMtDFBMQR8jRg9O75tm9K00oMsK4=
@@ -1111,8 +1113,9 @@ golang.org/x/sys v0.0.0-20210510120138-977fb7262007/go.mod h1:oPkhp1MJrh7nUepCBc
 golang.org/x/sys v0.0.0-20210603081109-ebe580a85c40/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20210615035016-665e8c7367d1/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20210616094352-59db8d763f22/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.0.0-20210630005230-0f9fa26af87c h1:F1jZWGFhYfh0Ci55sIpILtKKK8p3i2/krTr0H1rg74I=
 golang.org/x/sys v0.0.0-20210630005230-0f9fa26af87c/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.0.0-20211110154304-99a53858aa08 h1:WecRHqgE09JBkh/584XIE6PMz5KKE/vER4izNUi30AQ=
+golang.org/x/sys v0.0.0-20211110154304-99a53858aa08/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
 golang.org/x/term v0.0.0-20210503060354-a79de5458b56/go.mod h1:tfny5GFUkzUvx4ps4ajbZsCe5lw1metzhBm9T3x7oIY=
 golang.org/x/term v0.0.0-20210615171337-6886f2dfbf5b h1:9zKuko04nR4gjZ4+DNjHqRlAJqbJETHwiNKDqTfOjfE=

parser/parser.go

@@ -2,7 +2,6 @@ package parser
 
 import (
 	"bufio"
-	"encoding/json"
 	"os"
 	"path/filepath"
 	"strconv"
@@ -14,6 +13,7 @@ import (
 	"github.com/buger/jsonparser"
 	"github.com/icza/dyno"
 	"github.com/magiconair/properties"
+	"github.com/goccy/go-json"
 	"gopkg.in/ini.v1"
 	"gopkg.in/yaml.v2"
 
@@ -80,8 +80,8 @@ func (cp ConfigurationParser) String() string {
 	return string(cp)
 }
 
-// Defines a configuration file for the server startup. These will be looped over
-// and modified before the server finishes booting.
+// ConfigurationFile defines a configuration file for the server startup. These
+// will be looped over and modified before the server finishes booting.
 type ConfigurationFile struct {
 	FileName string                         `json:"file"`
 	Parser   ConfigurationParser            `json:"parser"`
@@ -92,12 +92,10 @@ type ConfigurationFile struct {
 	configuration []byte
 }
 
-// Custom unmarshaler for configuration files. If there is an error while parsing out the
-// replacements, don't fail the entire operation, just log a global warning so someone can
-// find the issue, and return an empty array of replacements.
-//
-// I imagine people will notice configuration replacement isn't working correctly and then
-// the logs should help better expose that issue.
+// UnmarshalJSON is a custom unmarshaler for configuration files. If there is an
+// error while parsing out the replacements, don't fail the entire operation,
+// just log a global warning so someone can find the issue, and return an empty
+// array of replacements.
 func (f *ConfigurationFile) UnmarshalJSON(data []byte) error {
 	var m map[string]*json.RawMessage
 	if err := json.Unmarshal(data, &m); err != nil {

remote/http.go

@@ -3,7 +3,6 @@ package remote
 import (
 	"bytes"
 	"context"
-	"encoding/json"
 	"fmt"
 	"io"
 	"net/http"
@@ -14,6 +13,7 @@ import (
 	"emperror.dev/errors"
 	"github.com/apex/log"
 	"github.com/cenkalti/backoff/v4"
+	"github.com/goccy/go-json"
 
 	"github.com/pterodactyl/wings/system"
 )

remote/types.go

@@ -1,11 +1,12 @@
 package remote
 
 import (
-	"encoding/json"
+	"bytes"
 	"regexp"
 	"strings"
 
 	"github.com/apex/log"
+	"github.com/goccy/go-json"
 
 	"github.com/pterodactyl/wings/parser"
 )
@@ -85,37 +86,38 @@ type SftpAuthResponse struct {
 type OutputLineMatcher struct {
 	// The raw string to match against. This may or may not be prefixed with
 	// regex: which indicates we want to match against the regex expression.
-	raw string
+	raw []byte
 	reg *regexp.Regexp
 }
 
-// Matches determines if a given string "s" matches the given line.
-func (olm *OutputLineMatcher) Matches(s string) bool {
+// Matches determines if the provided byte string matches the given regex or
+// raw string provided to the matcher.
+func (olm *OutputLineMatcher) Matches(s []byte) bool {
 	if olm.reg == nil {
-		return strings.Contains(s, olm.raw)
+		return bytes.Contains(s, olm.raw)
 	}
-
-	return olm.reg.MatchString(s)
+	return olm.reg.Match(s)
 }
 
 // String returns the matcher's raw comparison string.
 func (olm *OutputLineMatcher) String() string {
-	return olm.raw
+	return string(olm.raw)
 }
 
 // UnmarshalJSON unmarshals the startup lines into individual structs for easier
 // matching abilities.
 func (olm *OutputLineMatcher) UnmarshalJSON(data []byte) error {
-	if err := json.Unmarshal(data, &olm.raw); err != nil {
+	var r string
+	if err := json.Unmarshal(data, &r); err != nil {
 		return err
 	}
 
-	if strings.HasPrefix(olm.raw, "regex:") && len(olm.raw) > 6 {
-		r, err := regexp.Compile(strings.TrimPrefix(olm.raw, "regex:"))
+	olm.raw = []byte(r)
+	if bytes.HasPrefix(olm.raw, []byte("regex:")) && len(olm.raw) > 6 {
+		r, err := regexp.Compile(strings.TrimPrefix(string(olm.raw), "regex:"))
 		if err != nil {
-			log.WithField("error", err).WithField("raw", olm.raw).Warn("failed to compile output line marked as being regex")
+			log.WithField("error", err).WithField("raw", string(olm.raw)).Warn("failed to compile output line marked as being regex")
 		}
-
 		olm.reg = r
 	}
 

router/downloader/downloader.go

@@ -2,7 +2,6 @@ package downloader
 
 import (
 	"context"
-	"encoding/json"
 	"fmt"
 	"io"
 	"net"
@@ -15,6 +14,7 @@ import (
 
 	"emperror.dev/errors"
 	"github.com/google/uuid"
+	"github.com/goccy/go-json"
 
 	"github.com/pterodactyl/wings/server"
 )

router/router_server.go

@@ -52,7 +52,8 @@ func postServerPower(c *gin.Context) {
 	s := ExtractServer(c)
 
 	var data struct {
-		Action server.PowerAction `json:"action"`
+		Action      server.PowerAction `json:"action"`
+		WaitSeconds int                `json:"wait_seconds"`
 	}
 
 	if err := c.BindJSON(&data); err != nil {
@@ -83,12 +84,16 @@ func postServerPower(c *gin.Context) {
 	// we can immediately return a response from the server. Some of these actions
 	// can take quite some time, especially stopping or restarting.
 	go func(s *server.Server) {
-		if err := s.HandlePowerAction(data.Action, 30); err != nil {
+		if data.WaitSeconds < 0 || data.WaitSeconds > 300 {
+			data.WaitSeconds = 30
+		}
+		if err := s.HandlePowerAction(data.Action, data.WaitSeconds); err != nil {
 			if errors.Is(err, context.DeadlineExceeded) {
-				s.Log().WithField("action", data.Action).
-					Warn("could not acquire a lock while attempting to perform a power action")
+				s.Log().WithField("action", data.Action).WithField("error", err).Warn("could not process server power action")
+			} else if errors.Is(err, server.ErrIsRunning) {
+				// Do nothing, this isn't something we care about for logging,
 			} else {
-				s.Log().WithFields(log.Fields{"action": data, "error": err}).
+				s.Log().WithFields(log.Fields{"action": data.Action, "wait_seconds": data.WaitSeconds, "error": err}).
 					Error("encountered error processing a server power action in the background")
 			}
 		}
@@ -182,15 +187,7 @@ func deleteServer(c *gin.Context) {
 	// Immediately suspend the server to prevent a user from attempting
 	// to start it while this process is running.
 	s.Config().SetSuspended(true)
-
-	// Stop all running background tasks for this server that are using the context on
-	// the server struct. This will cancel any running install processes for the server
-	// as well.
-	s.CtxCancel()
-	s.Events().Destroy()
-	s.LogSink().Destroy()
-	s.InstallSink().Destroy()
-	s.Websockets().CancelAll()
+	s.CleanupForDestroy()
 
 	// Remove any pending remote file downloads for the server.
 	for _, dl := range downloader.ByServer(s.ID()) {

router/router_server_ws.go

@@ -2,11 +2,11 @@ package router
 
 import (
 	"context"
-	"encoding/json"
 	"time"
 
 	"github.com/gin-gonic/gin"
 	ws "github.com/gorilla/websocket"
+	"github.com/goccy/go-json"
 
 	"github.com/pterodactyl/wings/router/middleware"
 	"github.com/pterodactyl/wings/router/websocket"

router/tokens/websocket.go

@@ -1,13 +1,13 @@
 package tokens
 
 import (
-	"encoding/json"
 	"strings"
 	"sync"
 	"time"
 
 	"github.com/apex/log"
 	"github.com/gbrlsnchs/jwt/v3"
+	"github.com/goccy/go-json"
 )
 
 // The time at which Wings was booted. No JWT's created before this time are allowed to

router/websocket/listeners.go

@@ -2,11 +2,12 @@ package websocket
 
 import (
 	"context"
-	"encoding/json"
 	"sync"
 	"time"
 
 	"emperror.dev/errors"
+	"github.com/goccy/go-json"
+
 	"github.com/pterodactyl/wings/events"
 	"github.com/pterodactyl/wings/server"
 )
@@ -88,11 +89,11 @@ func (h *Handler) listenForServerEvents(ctx context.Context) error {
 	defer cancel()
 
 	eventChan := make(chan events.Event)
-	logOutput := make(chan []byte)
-	installOutput := make(chan []byte)
+	logOutput := make(chan []byte, 8)
+	installOutput := make(chan []byte, 4)
 	h.server.Events().On(eventChan, e...)
-	h.server.LogSink().On(logOutput)
-	h.server.InstallSink().On(installOutput)
+	h.server.Sink(server.LogSink).On(logOutput)
+	h.server.Sink(server.InstallSink).On(installOutput)
 
 	onError := func(evt string, err2 error) {
 		h.Logger().WithField("event", evt).WithField("error", err2).Error("failed to send event over server websocket")
@@ -148,8 +149,8 @@ func (h *Handler) listenForServerEvents(ctx context.Context) error {
 
 	// These functions will automatically close the channel if it hasn't been already.
 	h.server.Events().Off(eventChan, e...)
-	h.server.LogSink().Off(logOutput)
-	h.server.InstallSink().Off(installOutput)
+	h.server.Sink(server.LogSink).Off(logOutput)
+	h.server.Sink(server.InstallSink).Off(installOutput)
 
 	// If the internal context is stopped it is either because the parent context
 	// got canceled or because we ran into an error. If the "err" variable is nil

router/websocket/websocket.go

@@ -2,7 +2,6 @@ package websocket
 
 import (
 	"context"
-	"encoding/json"
 	"fmt"
 	"net/http"
 	"strings"
@@ -14,6 +13,7 @@ import (
 	"github.com/gbrlsnchs/jwt/v3"
 	"github.com/google/uuid"
 	"github.com/gorilla/websocket"
+	"github.com/goccy/go-json"
 
 	"github.com/pterodactyl/wings/config"
 	"github.com/pterodactyl/wings/environment"
@@ -267,18 +267,11 @@ func (h *Handler) setJwt(token *tokens.WebsocketPayload) {
 	h.Unlock()
 }
 
-var actions = map[server.PowerAction]string{
-	server.PowerActionStart:     PermissionSendPowerStart,
-	server.PowerActionStop:      PermissionSendPowerStop,
-	server.PowerActionRestart:   PermissionSendPowerRestart,
-	server.PowerActionTerminate: PermissionSendPowerStop,
-}
-
 // HandleInbound handles an inbound socket request and route it to the proper action.
 func (h *Handler) HandleInbound(ctx context.Context, m Message) error {
 	if m.Event != AuthenticationEvent {
 		if err := h.TokenValid(); err != nil {
-			_ = h.unsafeSendJson(Message{
+			h.unsafeSendJson(Message{
 				Event: JwtErrorEvent,
 				Args:  []string{err.Error()},
 			})
@@ -346,6 +339,12 @@ func (h *Handler) HandleInbound(ctx context.Context, m Message) error {
 		{
 			action := server.PowerAction(strings.Join(m.Args, ""))
 
+			actions := make(map[server.PowerAction]string)
+			actions[server.PowerActionStart] = PermissionSendPowerStart
+			actions[server.PowerActionStop] = PermissionSendPowerStop
+			actions[server.PowerActionRestart] = PermissionSendPowerRestart
+			actions[server.PowerActionTerminate] = PermissionSendPowerStop
+
 			// Check that they have permission to perform this action if it is needed.
 			if permission, exists := actions[action]; exists {
 				if !h.GetJwt().HasPermission(permission) {

server/console.go

@@ -1,15 +1,11 @@
 package server
 
 import (
-	"context"
 	"fmt"
 	"sync"
-	"sync/atomic"
 	"time"
 
-	"emperror.dev/errors"
 	"github.com/mitchellh/colorstring"
-
 	"github.com/pterodactyl/wings/config"
 	"github.com/pterodactyl/wings/system"
 )
@@ -18,118 +14,8 @@ import (
 // the configuration every time we need to send output along to the websocket for
 // a server.
 var appName string
-
 var appNameSync sync.Once
 
-var ErrTooMuchConsoleData = errors.New("console is outputting too much data")
-
-type ConsoleThrottler struct {
-	mu sync.Mutex
-	config.ConsoleThrottles
-
-	// The total number of activations that have occurred thus far.
-	activations uint64
-
-	// The total number of lines that have been sent since the last reset timer period.
-	count uint64
-
-	// Wether or not the console output is being throttled. It is up to calling code to
-	// determine what to do if it is.
-	isThrottled *system.AtomicBool
-
-	// The total number of lines processed so far during the given time period.
-	timerCancel *context.CancelFunc
-}
-
-// Resets the state of the throttler.
-func (ct *ConsoleThrottler) Reset() {
-	atomic.StoreUint64(&ct.count, 0)
-	atomic.StoreUint64(&ct.activations, 0)
-	ct.isThrottled.Store(false)
-}
-
-// Triggers an activation for a server. You can also decrement the number of activations
-// by passing a negative number.
-func (ct *ConsoleThrottler) markActivation(increment bool) uint64 {
-	if !increment {
-		if atomic.LoadUint64(&ct.activations) == 0 {
-			return 0
-		}
-
-		// This weird dohicky subtracts 1 from the activation count.
-		return atomic.AddUint64(&ct.activations, ^uint64(0))
-	}
-
-	return atomic.AddUint64(&ct.activations, 1)
-}
-
-// Determines if the console is currently being throttled. Calls to this function can be used to
-// determine if output should be funneled along to the websocket processes.
-func (ct *ConsoleThrottler) Throttled() bool {
-	return ct.isThrottled.Load()
-}
-
-// Starts a timer that runs in a seperate thread and will continually decrement the lines processed
-// and number of activations, regardless of the current console message volume. All of the timers
-// are canceled if the context passed through is canceled.
-func (ct *ConsoleThrottler) StartTimer(ctx context.Context) {
-	system.Every(ctx, time.Duration(int64(ct.LineResetInterval))*time.Millisecond, func(_ time.Time) {
-		ct.isThrottled.Store(false)
-		atomic.StoreUint64(&ct.count, 0)
-	})
-
-	system.Every(ctx, time.Duration(int64(ct.DecayInterval))*time.Millisecond, func(_ time.Time) {
-		ct.markActivation(false)
-	})
-}
-
-// Handles output from a server's console. This code ensures that a server is not outputting
-// an excessive amount of data to the console that could indicate a malicious or run-away process
-// and lead to performance issues for other users.
-//
-// This was much more of a problem for the NodeJS version of the daemon which struggled to handle
-// large volumes of output. However, this code is much more performant so I generally feel a lot
-// better about it's abilities.
-//
-// However, extreme output is still somewhat of a DoS attack vector against this software since we
-// are still logging it to the disk temporarily and will want to avoid dumping a huge amount of
-// data all at once. These values are all configurable via the wings configuration file, however the
-// defaults have been in the wild for almost two years at the time of this writing, so I feel quite
-// confident in them.
-//
-// This function returns an error if the server should be stopped due to violating throttle constraints
-// and a boolean value indicating if a throttle is being violated when it is checked.
-func (ct *ConsoleThrottler) Increment(onTrigger func()) error {
-	if !ct.Enabled {
-		return nil
-	}
-
-	// Increment the line count and if we have now output more lines than are allowed, trigger a throttle
-	// activation. Once the throttle is triggered and has passed the kill at value we will trigger a server
-	// stop automatically.
-	if atomic.AddUint64(&ct.count, 1) >= ct.Lines && !ct.Throttled() {
-		ct.isThrottled.Store(true)
-		if ct.markActivation(true) >= ct.MaximumTriggerCount {
-			return ErrTooMuchConsoleData
-		}
-
-		onTrigger()
-	}
-
-	return nil
-}
-
-// Returns the throttler instance for the server or creates a new one.
-func (s *Server) Throttler() *ConsoleThrottler {
-	s.throttleOnce.Do(func() {
-		s.throttler = &ConsoleThrottler{
-			isThrottled:      system.NewAtomicBool(false),
-			ConsoleThrottles: config.Get().Throttles,
-		}
-	})
-	return s.throttler
-}
-
 // PublishConsoleOutputFromDaemon sends output to the server console formatted
 // to appear correctly as being sent from Wings.
 func (s *Server) PublishConsoleOutputFromDaemon(data string) {
@@ -141,3 +27,55 @@ func (s *Server) PublishConsoleOutputFromDaemon(data string) {
 		colorstring.Color(fmt.Sprintf("[yellow][bold][%s Daemon]:[default] %s", appName, data)),
 	)
 }
+
+// Throttler returns the throttler instance for the server or creates a new one.
+func (s *Server) Throttler() *ConsoleThrottle {
+	s.throttleOnce.Do(func() {
+		throttles := config.Get().Throttles
+		period := time.Duration(throttles.Period) * time.Millisecond
+
+		s.throttler = newConsoleThrottle(throttles.Lines, period)
+		s.throttler.strike = func() {
+			s.PublishConsoleOutputFromDaemon(fmt.Sprintf("Server is outputting console data too quickly -- throttling..."))
+		}
+	})
+	return s.throttler
+}
+
+type ConsoleThrottle struct {
+	limit  *system.Rate
+	lock   *system.Locker
+	strike func()
+}
+
+func newConsoleThrottle(lines uint64, period time.Duration) *ConsoleThrottle {
+	return &ConsoleThrottle{
+		limit: system.NewRate(lines, period),
+		lock:  system.NewLocker(),
+	}
+}
+
+// Allow checks if the console is allowed to process more output data, or if too
+// much has already been sent over the line. If there is too much output the
+// strike callback function is triggered, but only if it has not already been
+// triggered at this point in the process.
+//
+// If output is allowed, the lock on the throttler is released and the next time
+// it is triggered the strike function will be re-executed.
+func (ct *ConsoleThrottle) Allow() bool {
+	if !ct.limit.Try() {
+		if err := ct.lock.Acquire(); err == nil {
+			if ct.strike != nil {
+				ct.strike()
+			}
+		}
+		return false
+	}
+	ct.lock.Release()
+	return true
+}
+
+// Reset resets the console throttler internal rate limiter and overage counter.
+func (ct *ConsoleThrottle) Reset() {
+	ct.limit.Reset()
+}

server/console_test.go

@@ -0,0 +1,62 @@
+package server
+
+import (
+	"testing"
+	"time"
+
+	"github.com/franela/goblin"
+)
+
+func TestName(t *testing.T) {
+	g := goblin.Goblin(t)
+
+	g.Describe("ConsoleThrottler", func() {
+		g.It("keeps count of the number of overages in a time period", func() {
+			t := newConsoleThrottle(1, time.Second)
+			g.Assert(t.Allow()).IsTrue()
+			g.Assert(t.Allow()).IsFalse()
+			g.Assert(t.Allow()).IsFalse()
+		})
+
+		g.It("calls strike once per time period", func() {
+			t := newConsoleThrottle(1, time.Millisecond * 20)
+
+			var times int
+			t.strike = func() {
+				times = times + 1
+			}
+
+			t.Allow()
+			t.Allow()
+			t.Allow()
+			time.Sleep(time.Millisecond * 100)
+			t.Allow()
+			t.Reset()
+			t.Allow()
+			t.Allow()
+			t.Allow()
+
+			g.Assert(times).Equal(2)
+		})
+
+		g.It("is properly reset", func() {
+			t := newConsoleThrottle(10, time.Second)
+
+			for i := 0; i < 10; i++ {
+				g.Assert(t.Allow()).IsTrue()
+			}
+			g.Assert(t.Allow()).IsFalse()
+			t.Reset()
+			g.Assert(t.Allow()).IsTrue()
+		})
+	})
+}
+
+func BenchmarkConsoleThrottle(b *testing.B) {
+	t := newConsoleThrottle(10, time.Millisecond * 10)
+
+	b.ReportAllocs()
+    for i := 0; i < b.N; i++ {
+        t.Allow()
+    }
+}

server/filesystem/stat.go

@@ -1,12 +1,12 @@
 package filesystem
 
 import (
-	"encoding/json"
 	"os"
 	"strconv"
 	"time"
 
 	"github.com/gabriel-vasile/mimetype"
+	"github.com/goccy/go-json"
 )
 
 type Stat struct {

server/install.go

@@ -507,9 +507,9 @@ func (ip *InstallationProcess) Execute() (string, error) {
 	return r.ID, nil
 }
 
-// Streams the output of the installation process to a log file in the server configuration
-// directory, as well as to a websocket listener so that the process can be viewed in
-// the panel by administrators.
+// StreamOutput streams the output of the installation process to a log file in
+// the server configuration directory, as well as to a websocket listener so
+// that the process can be viewed in the panel by administrators.
 func (ip *InstallationProcess) StreamOutput(ctx context.Context, id string) error {
 	reader, err := ip.client.ContainerLogs(ctx, id, types.ContainerLogsOptions{
 		ShowStdout: true,
@@ -521,7 +521,7 @@ func (ip *InstallationProcess) StreamOutput(ctx context.Context, id string) erro
 	}
 	defer reader.Close()
 
-	err = system.ScanReader(reader, ip.Server.InstallSink().Push)
+	err = system.ScanReader(reader, ip.Server.Sink(InstallSink).Push)
 	if err != nil {
 		ip.Server.Log().WithFields(log.Fields{"container_id": id, "error": err}).Warn("error processing install output lines")
 	}

server/listeners.go

@@ -1,13 +1,13 @@
 package server
 
 import (
+	"bytes"
 	"regexp"
 	"strconv"
 	"sync"
 
 	"github.com/apex/log"
 
-	"github.com/pterodactyl/wings/config"
 	"github.com/pterodactyl/wings/environment"
 	"github.com/pterodactyl/wings/events"
 	"github.com/pterodactyl/wings/remote"
@@ -50,48 +50,34 @@ func (dsl *diskSpaceLimiter) Trigger() {
 	})
 }
 
+// processConsoleOutputEvent handles output from a server's Docker container
+// and runs through different limiting logic to ensure that spam console output
+// does not cause negative effects to the system. This will also monitor the
+// output lines to determine if the server is started yet, and if the output is
+// not being throttled, will send the data over to the websocket.
 func (s *Server) processConsoleOutputEvent(v []byte) {
-	t := s.Throttler()
-	err := t.Increment(func() {
-		s.PublishConsoleOutputFromDaemon("Your server is outputting too much data and is being throttled.")
-	})
-	// An error is only returned if the server has breached the thresholds set.
-	if err != nil {
-		// If the process is already stopping, just let it continue with that action rather than attempting
-		// to terminate again.
-		if s.Environment.State() != environment.ProcessStoppingState {
-			s.Environment.SetState(environment.ProcessStoppingState)
+	// Always process the console output, but do this in a seperate thread since we
+	// don't really care about side-effects from this call, and don't want it to block
+	// the console sending logic.
+	go s.onConsoleOutput(v)
 
-			go func() {
-				s.Log().Warn("stopping server instance, violating throttle limits")
-				s.PublishConsoleOutputFromDaemon("Your server is being stopped for outputting too much data in a short period of time.")
-
-				// Completely skip over server power actions and terminate the running instance. This gives the
-				// server 15 seconds to finish stopping gracefully before it is forcefully terminated.
-				if err := s.Environment.WaitForStop(config.Get().Throttles.StopGracePeriod, true); err != nil {
-					// If there is an error set the process back to running so that this throttler is called
-					// again and hopefully kills the server.
-					if s.Environment.State() != environment.ProcessOfflineState {
-						s.Environment.SetState(environment.ProcessRunningState)
-					}
-
-					s.Log().WithField("error", err).Error("failed to terminate environment after triggering throttle")
-				}
-			}()
-		}
+	// If the console is being throttled, do nothing else with it, we don't want
+	// to waste time. This code previously terminated server instances after violating
+	// different throttle limits. That code was clunky and difficult to reason about,
+	// in addition to being a consistent pain point for users.
+	//
+	// In the interest of building highly efficient software, that code has been removed
+	// here, and we'll rely on the host to detect bad actors through their own means.
+	if !s.Throttler().Allow() {
+		return
 	}
 
-	// If we are not throttled, go ahead and output the data.
-	if !t.Throttled() {
-		s.LogSink().Push(v)
-	}
-
-	// Also pass the data along to the console output channel.
-	s.onConsoleOutput(string(v))
+	s.Sink(LogSink).Push(v)
 }
 
-// StartEventListeners adds all the internal event listeners we want to use for a server. These listeners can only be
-// removed by deleting the server as they should last for the duration of the process' lifetime.
+// StartEventListeners adds all the internal event listeners we want to use for
+// a server. These listeners can only be removed by deleting the server as they
+// should last for the duration of the process' lifetime.
 func (s *Server) StartEventListeners() {
 	state := make(chan events.Event)
 	stats := make(chan events.Event)
@@ -114,18 +100,15 @@ func (s *Server) StartEventListeners() {
 				}()
 			case e := <-stats:
 				go func() {
-					// Update the server resource tracking object with the resources we got here.
-					s.resources.mu.Lock()
-					s.resources.Stats = e.Data.(environment.Stats)
-					s.resources.mu.Unlock()
+					s.resources.UpdateStats(e.Data.(environment.Stats))
 
-					// If there is no disk space available at this point, trigger the server disk limiter logic
-					// which will start to stop the running instance.
+					// If there is no disk space available at this point, trigger the server
+					// disk limiter logic which will start to stop the running instance.
 					if !s.Filesystem().HasSpaceAvailable(true) {
 						l.Trigger()
 					}
 
-					s.emitProcUsage()
+					s.Events().Publish(StatsEvent, s.Proc())
 				}()
 			case e := <-docker:
 				go func() {
@@ -134,8 +117,10 @@ func (s *Server) StartEventListeners() {
 						s.Events().Publish(InstallOutputEvent, e.Data)
 					case environment.DockerImagePullStarted:
 						s.PublishConsoleOutputFromDaemon("Pulling Docker container image, this could take a few minutes to complete...")
-					default:
+					case environment.DockerImagePullCompleted:
 						s.PublishConsoleOutputFromDaemon("Finished pulling Docker container image")
+					default:
+						s.Log().WithField("topic", e.Topic).Error("unhandled docker event topic")
 					}
 				}()
 			}
@@ -153,27 +138,34 @@ var stripAnsiRegex = regexp.MustCompile("[\u001B\u009B][[\\]()#;?]*(?:(?:(?:[a-z
 
 // Custom listener for console output events that will check if the given line
 // of output matches one that should mark the server as started or not.
-func (s *Server) onConsoleOutput(data string) {
-	// Get the server's process configuration.
+func (s *Server) onConsoleOutput(data []byte) {
+	if s.Environment.State() != environment.ProcessStartingState && !s.IsRunning() {
+		return
+	}
+
 	processConfiguration := s.ProcessConfiguration()
 
+	// Make a copy of the data provided since it is by reference, otherwise you'll
+	// potentially introduce a race condition by modifying the value.
+	v := make([]byte, len(data))
+	copy(v, data)
+
 	// Check if the server is currently starting.
 	if s.Environment.State() == environment.ProcessStartingState {
 		// Check if we should strip ansi color codes.
 		if processConfiguration.Startup.StripAnsi {
-			// Strip ansi color codes from the data string.
-			data = stripAnsiRegex.ReplaceAllString(data, "")
+			v = stripAnsiRegex.ReplaceAll(v, []byte(""))
 		}
 
 		// Iterate over all the done lines.
 		for _, l := range processConfiguration.Startup.Done {
-			if !l.Matches(data) {
+			if !l.Matches(v) {
 				continue
 			}
 
 			s.Log().WithFields(log.Fields{
 				"match":   l.String(),
-				"against": strconv.QuoteToASCII(data),
+				"against": strconv.QuoteToASCII(string(v)),
 			}).Debug("detected server in running state based on console line output")
 
 			// If the specific line of output is one that would mark the server as started,
@@ -190,7 +182,7 @@ func (s *Server) onConsoleOutput(data string) {
 	if s.IsRunning() {
 		stop := processConfiguration.Stop
 
-		if stop.Type == remote.ProcessStopCommand && data == stop.Value {
+		if stop.Type == remote.ProcessStopCommand && bytes.Equal(v, []byte(stop.Value)) {
 			s.Environment.SetState(environment.ProcessOfflineState)
 		}
 	}

server/manager.go

@@ -2,7 +2,6 @@ package server
 
 import (
 	"context"
-	"encoding/json"
 	"fmt"
 	"io"
 	"os"
@@ -14,6 +13,7 @@ import (
 	"emperror.dev/errors"
 	"github.com/apex/log"
 	"github.com/gammazero/workerpool"
+	"github.com/goccy/go-json"
 
 	"github.com/pterodactyl/wings/config"
 	"github.com/pterodactyl/wings/environment"
@@ -199,7 +199,6 @@ func (m *Manager) InitServer(data remote.ServerConfigurationResponse) (*Server,
 	} else {
 		s.Environment = env
 		s.StartEventListeners()
-		s.Throttler().StartTimer(s.Context())
 	}
 
 	// If the server's data directory exists, force disk usage calculation.

server/power.go

@@ -2,12 +2,12 @@ package server
 
 import (
 	"context"
+	"fmt"
 	"os"
 	"time"
 
 	"emperror.dev/errors"
-	"golang.org/x/sync/semaphore"
-
+	"github.com/google/uuid"
 	"github.com/pterodactyl/wings/config"
 	"github.com/pterodactyl/wings/environment"
 )
@@ -40,19 +40,10 @@ func (pa PowerAction) IsStart() bool {
 	return pa == PowerActionStart || pa == PowerActionRestart
 }
 
-// ExecutingPowerAction checks if there is currently a power action being processed for the server.
+// ExecutingPowerAction checks if there is currently a power action being
+// processed for the server.
 func (s *Server) ExecutingPowerAction() bool {
-	if s.powerLock == nil {
-		return false
-	}
-
-	ok := s.powerLock.TryAcquire(1)
-	if ok {
-		s.powerLock.Release(1)
-	}
-
-	// Remember, if we acquired a lock it means nothing was running.
-	return !ok
+	return s.powerLock.IsLocked()
 }
 
 // HandlePowerAction is a helper function that can receive a power action and then process the
@@ -63,22 +54,29 @@ func (s *Server) ExecutingPowerAction() bool {
 // function rather than making direct calls to the start/stop/restart functions on the
 // environment struct.
 func (s *Server) HandlePowerAction(action PowerAction, waitSeconds ...int) error {
-	if s.IsInstalling() {
+	if s.IsInstalling() || s.IsTransferring() || s.IsRestoring() {
+		if s.IsRestoring() {
+			return ErrServerIsRestoring
+		} else if s.IsTransferring() {
+			return ErrServerIsTransferring
+		}
 		return ErrServerIsInstalling
 	}
 
-	if s.IsTransferring() {
-		return ErrServerIsTransferring
+	lockId, _ := uuid.NewUUID()
+	log := s.Log().WithField("lock_id", lockId.String()).WithField("action", action)
+
+	cleanup := func() {
+		log.Info("releasing exclusive lock for power action")
+		s.powerLock.Release()
 	}
 
-	if s.IsRestoring() {
-		return ErrServerIsRestoring
-	}
-
-	if s.powerLock == nil {
-		s.powerLock = semaphore.NewWeighted(1)
+	var wait int
+	if len(waitSeconds) > 0 && waitSeconds[0] > 0 {
+		wait = waitSeconds[0]
 	}
 
+	log.WithField("wait_seconds", wait).Debug("acquiring power action lock for instance")
 	// Only attempt to acquire a lock on the process if this is not a termination event. We want to
 	// just allow those events to pass right through for good reason. If a server is currently trying
 	// to process a power action but has gotten stuck you still should be able to pass through the
@@ -87,33 +85,38 @@ func (s *Server) HandlePowerAction(action PowerAction, waitSeconds ...int) error
 	if action != PowerActionTerminate {
 		// Determines if we should wait for the lock or not. If a value greater than 0 is passed
 		// into this function we will wait that long for a lock to be acquired.
-		if len(waitSeconds) > 0 && waitSeconds[0] != 0 {
-			ctx, cancel := context.WithTimeout(context.Background(), time.Second*time.Duration(waitSeconds[0]))
+		if wait > 0 {
+			ctx, cancel := context.WithTimeout(s.ctx, time.Second*time.Duration(wait))
 			defer cancel()
 
 			// Attempt to acquire a lock on the power action lock for up to 30 seconds. If more
 			// time than that passes an error will be propagated back up the chain and this
 			// request will be aborted.
-			if err := s.powerLock.Acquire(ctx, 1); err != nil {
-				return errors.WithMessage(err, "could not acquire lock on power state")
+			if err := s.powerLock.TryAcquire(ctx); err != nil {
+				return errors.Wrap(err, fmt.Sprintf("could not acquire lock on power action after %d seconds", wait))
 			}
 		} else {
 			// If no wait duration was provided we will attempt to immediately acquire the lock
 			// and bail out with a context deadline error if it is not acquired immediately.
-			if ok := s.powerLock.TryAcquire(1); !ok {
-				return errors.WithMessage(context.DeadlineExceeded, "could not acquire lock on power state")
+			if err := s.powerLock.Acquire(); err != nil {
+				return errors.Wrap(err, "failed to acquire exclusive lock for power actions")
 			}
 		}
 
-		// Release the lock once the process being requested has finished executing.
-		defer s.powerLock.Release(1)
+		log.Info("acquired exclusive lock on power actions, processing event...")
+		defer cleanup()
 	} else {
-		// Still try to acquire the lock if terminating, and it is available, just so that other power
-		// actions are blocked until it has completed. However, if it is unavailable we won't stop
-		// the entire process.
-		if ok := s.powerLock.TryAcquire(1); ok {
-			// If we managed to acquire the lock be sure to released it once this process is completed.
-			defer s.powerLock.Release(1)
+		// Still try to acquire the lock if terminating, and it is available, just so that
+		// other power actions are blocked until it has completed. However, if it cannot be
+		// acquired we won't stop the entire process.
+		//
+		// If we did successfully acquire the lock, make sure we release it once we're done
+		// executiong the power actions.
+		if err := s.powerLock.Acquire(); err == nil {
+			log.Info("acquired exclusive lock on power actions, processing event...")
+			defer cleanup()
+		} else {
+			log.Warn("failed to acquire exclusive lock, ignoring failure for termination event")
 		}
 	}
 

server/power_test.go

@@ -0,0 +1,22 @@
+package server
+
+import (
+	"testing"
+
+	. "github.com/franela/goblin"
+	"github.com/pterodactyl/wings/system"
+)
+
+func TestPower(t *testing.T) {
+	g := Goblin(t)
+
+	g.Describe("Server#ExecutingPowerAction", func() {
+		g.It("should return based on locker status", func() {
+			s := &Server{powerLock: system.NewLocker()}
+
+			g.Assert(s.ExecutingPowerAction()).IsFalse()
+			s.powerLock.Acquire()
+			g.Assert(s.ExecutingPowerAction()).IsTrue()
+		})
+	})
+}

server/resources.go

@@ -38,6 +38,13 @@ func (s *Server) Proc() ResourceUsage {
 	return s.resources
 }
 
+// UpdateStats updates the current stats for the server's resource usage.
+func (ru *ResourceUsage) UpdateStats(stats environment.Stats) {
+	ru.mu.Lock()
+	ru.Stats = stats
+	ru.mu.Unlock()
+}
+
 // Reset resets the usages values to zero, used when a server is stopped to ensure we don't hold
 // onto any values incorrectly.
 func (ru *ResourceUsage) Reset() {
@@ -50,7 +57,3 @@ func (ru *ResourceUsage) Reset() {
 	ru.Network.TxBytes = 0
 	ru.Network.RxBytes = 0
 }
-
-func (s *Server) emitProcUsage() {
-	s.Events().Publish(StatsEvent, s.Proc())
-}

server/server.go

@@ -2,7 +2,6 @@ package server
 
 import (
 	"context"
-	"encoding/json"
 	"fmt"
 	"net/http"
 	"os"
@@ -12,7 +11,7 @@ import (
 	"emperror.dev/errors"
 	"github.com/apex/log"
 	"github.com/creasty/defaults"
-	"golang.org/x/sync/semaphore"
+	"github.com/goccy/go-json"
 
 	"github.com/pterodactyl/wings/config"
 	"github.com/pterodactyl/wings/environment"
@@ -31,9 +30,8 @@ type Server struct {
 	ctx       context.Context
 	ctxCancel *context.CancelFunc
 
-	emitterLock  sync.Mutex
-	powerLock    *semaphore.Weighted
-	throttleOnce sync.Once
+	emitterLock sync.Mutex
+	powerLock   *system.Locker
 
 	// Maintains the configuration for the server. This is the data that gets returned by the Panel
 	// such as build settings and container images.
@@ -65,12 +63,15 @@ type Server struct {
 	restoring    *system.AtomicBool
 
 	// The console throttler instance used to control outputs.
-	throttler *ConsoleThrottler
+	throttler    *ConsoleThrottle
+	throttleOnce sync.Once
 
 	// Tracks open websocket connections for the server.
 	wsBag       *WebsocketBag
 	wsBagLocker sync.Mutex
 
+	sinks map[SinkName]*sinkPool
+
 	logSink     *sinkPool
 	installSink *sinkPool
 }
@@ -86,9 +87,11 @@ func New(client remote.Client) (*Server, error) {
 		installing:   system.NewAtomicBool(false),
 		transferring: system.NewAtomicBool(false),
 		restoring:    system.NewAtomicBool(false),
-
-		logSink:     newSinkPool(),
-		installSink: newSinkPool(),
+		powerLock:    system.NewLocker(),
+		sinks: map[SinkName]*sinkPool{
+			LogSink:     newSinkPool(),
+			InstallSink: newSinkPool(),
+		},
 	}
 	if err := defaults.Set(&s); err != nil {
 		return nil, errors.Wrap(err, "server: could not set default values for struct")
@@ -100,6 +103,17 @@ func New(client remote.Client) (*Server, error) {
 	return &s, nil
 }
 
+// CleanupForDestroy stops all running background tasks for this server that are
+// using the context on the server struct. This will cancel any running install
+// processes for the server as well.
+func (s *Server) CleanupForDestroy() {
+	s.CtxCancel()
+	s.Events().Destroy()
+	s.DestroyAllSinks()
+	s.Websockets().CancelAll()
+	s.powerLock.Destroy()
+}
+
 // ID returns the UUID for the server instance.
 func (s *Server) ID() string {
 	return s.Config().GetUuid()
@@ -225,14 +239,6 @@ func (s *Server) ReadLogfile(len int) ([]string, error) {
 	return s.Environment.Readlog(len)
 }
 
-// Determine if the server is bootable in it's current state or not. This will not
-// indicate why a server is not bootable, only if it is.
-func (s *Server) IsBootable() bool {
-	exists, _ := s.Environment.Exists()
-
-	return exists
-}
-
 // Initializes a server instance. This will run through and ensure that the environment
 // for the server is setup, and that all of the necessary files are created.
 func (s *Server) CreateEnvironment() error {
@@ -299,7 +305,7 @@ func (s *Server) OnStateChange() {
 	// views in the Panel correctly display 0.
 	if st == environment.ProcessOfflineState {
 		s.resources.Reset()
-		s.emitProcUsage()
+		s.Events().Publish(StatsEvent, s.Proc())
 	}
 
 	// If server was in an online state, and is now in an offline state we should handle
@@ -355,11 +361,3 @@ func (s *Server) ToAPIResponse() APIResponse {
 		Configuration: *s.Config(),
 	}
 }
-
-func (s *Server) LogSink() *sinkPool {
-	return s.logSink
-}
-
-func (s *Server) InstallSink() *sinkPool {
-	return s.installSink
-}

server/sink.go

@@ -2,67 +2,141 @@ package server
 
 import (
 	"sync"
+	"time"
+)
+
+// SinkName represents one of the registered sinks for a server.
+type SinkName string
+
+const (
+	// LogSink handles console output for game servers, including messages being
+	// sent via Wings to the console instance.
+	LogSink SinkName = "log"
+	// InstallSink handles installation output for a server.
+	InstallSink SinkName = "install"
 )
 
 // sinkPool represents a pool with sinks.
 type sinkPool struct {
-	mx    sync.RWMutex
+	mu    sync.RWMutex
 	sinks []chan []byte
 }
 
-// newSinkPool returns a new empty sinkPool.
+// newSinkPool returns a new empty sinkPool. A sink pool generally lives with a
+// server instance for it's full lifetime.
 func newSinkPool() *sinkPool {
 	return &sinkPool{}
 }
 
-// Off removes a sink from the pool.
+// On adds a channel to the sink pool instance.
+func (p *sinkPool) On(c chan []byte) {
+	p.mu.Lock()
+	p.sinks = append(p.sinks, c)
+	p.mu.Unlock()
+}
+
+// Off removes a given channel from the sink pool. If no matching sink is found
+// this function is a no-op. If a matching channel is found, it will be removed.
 func (p *sinkPool) Off(c chan []byte) {
-	p.mx.Lock()
-	defer p.mx.Unlock()
+	p.mu.Lock()
+	defer p.mu.Unlock()
 
 	sinks := p.sinks
-
 	for i, sink := range sinks {
 		if c != sink {
 			continue
 		}
+
+		// We need to maintain the order of the sinks in the slice we're tracking,
+		// so shift everything to the left, rather than changing the order of the
+		// elements.
 		copy(sinks[i:], sinks[i+1:])
 		sinks[len(sinks)-1] = nil
 		sinks = sinks[:len(sinks)-1]
 		p.sinks = sinks
-		close(c)
+
+		// Avoid a panic if the sink channel is nil at this point.
+		if c != nil {
+			close(c)
+		}
+
 		return
 	}
 }
 
-// On adds a sink on the pool.
-func (p *sinkPool) On(c chan []byte) {
-	p.mx.Lock()
-	defer p.mx.Unlock()
-
-	p.sinks = append(p.sinks, c)
-}
-
-// Destroy destroys the pool by removing and closing all sinks.
+// Destroy destroys the pool by removing and closing all sinks and destroying
+// all of the channels that are present.
 func (p *sinkPool) Destroy() {
-	p.mx.Lock()
-	defer p.mx.Unlock()
+	p.mu.Lock()
+	defer p.mu.Unlock()
 
 	for _, c := range p.sinks {
-		close(c)
+		if c != nil {
+			close(c)
+		}
 	}
 
 	p.sinks = nil
 }
 
-// Push pushes a message to all registered sinks.
-func (p *sinkPool) Push(v []byte) {
-	p.mx.RLock()
+// Push sends a given message to each of the channels registered in the pool.
+// This will use a Ring Buffer channel in order to avoid blocking the channel
+// sends, and attempt to push though the most recent messages in the queue in
+// favor of the oldest messages.
+//
+// If the channel becomes full and isn't being drained fast enough, this
+// function will remove the oldest message in the channel, and then push the
+// message that it got onto the end, effectively making the channel a rolling
+// buffer.
+//
+// There is a potential for data to be lost when passing it through this
+// function, but only in instances where the channel buffer is full and the
+// channel is not drained fast enough, in which case dropping messages is most
+// likely the best option anyways. This uses waitgroups to allow every channel
+// to attempt its send concurrently thus making the total blocking time of this
+// function "O(1)" instead of "O(n)".
+func (p *sinkPool) Push(data []byte) {
+	p.mu.RLock()
+	defer p.mu.RUnlock()
+	var wg sync.WaitGroup
+	wg.Add(len(p.sinks))
 	for _, c := range p.sinks {
-		select {
-		// Send the log output to the channel
-		case c <- v:
-		}
+		go func(c chan []byte) {
+			defer wg.Done()
+			select {
+			case c <- data:
+			case <-time.After(time.Millisecond * 10):
+				// If there is nothing in the channel to read, but we also cannot write
+				// to the channel, just skip over sending data. If we don't do this you'll
+				// end up blocking the application on the channel read below.
+				if len(c) == 0 {
+					break
+				}
+				<-c
+				c <- data
+			}
+		}(c)
+	}
+	wg.Wait()
+}
+
+// Sink returns the instantiated and named sink for a server. If the sink has
+// not been configured yet this function will cause a panic condition.
+func (s *Server) Sink(name SinkName) *sinkPool {
+	sink, ok := s.sinks[name]
+	if !ok {
+		s.Log().Fatalf("attempt to access nil sink: %s", name)
+	}
+	return sink
+}
+
+// DestroyAllSinks iterates over all of the sinks configured for the server and
+// destroys their instances. Note that this will cause a panic if you attempt
+// to call Server.Sink() again after. This function is only used when a server
+// is being deleted from the system.
+func (s *Server) DestroyAllSinks() {
+	s.Log().Info("destroying all registered sinks for server instance")
+	for _, sink := range s.sinks {
+		sink.Destroy()
 	}
-	p.mx.RUnlock()
 }

server/sink_test.go

@@ -0,0 +1,236 @@
+package server
+
+import (
+	"fmt"
+	"reflect"
+	"sync"
+	"testing"
+	"time"
+
+	. "github.com/franela/goblin"
+)
+
+func MutexLocked(m *sync.RWMutex) bool {
+	v := reflect.ValueOf(m).Elem()
+
+	state := v.FieldByName("w").FieldByName("state")
+
+	return state.Int()&1 == 1 || v.FieldByName("readerCount").Int() > 0
+}
+
+func TestSink(t *testing.T) {
+	g := Goblin(t)
+
+	g.Describe("SinkPool#On", func() {
+		g.It("pushes additional channels to a sink", func() {
+			pool := &sinkPool{}
+
+			g.Assert(pool.sinks).IsZero()
+
+			c1 := make(chan []byte, 1)
+			pool.On(c1)
+
+			g.Assert(len(pool.sinks)).Equal(1)
+			g.Assert(MutexLocked(&pool.mu)).IsFalse()
+		})
+	})
+
+	g.Describe("SinkPool#Off", func() {
+		var pool *sinkPool
+		g.BeforeEach(func() {
+			pool = &sinkPool{}
+		})
+
+		g.It("works when no sinks are registered", func() {
+			ch := make(chan []byte, 1)
+
+			g.Assert(pool.sinks).IsZero()
+			pool.Off(ch)
+
+			g.Assert(pool.sinks).IsZero()
+			g.Assert(MutexLocked(&pool.mu)).IsFalse()
+		})
+
+		g.It("does not remove any sinks when the channel does not match", func() {
+			ch := make(chan []byte, 1)
+			ch2 := make(chan []byte, 1)
+
+			pool.On(ch)
+			g.Assert(len(pool.sinks)).Equal(1)
+
+			pool.Off(ch2)
+			g.Assert(len(pool.sinks)).Equal(1)
+			g.Assert(pool.sinks[0]).Equal(ch)
+			g.Assert(MutexLocked(&pool.mu)).IsFalse()
+		})
+
+		g.It("removes a channel and maintains the order", func() {
+			channels := make([]chan []byte, 8)
+			for i := 0; i < len(channels); i++ {
+				channels[i] = make(chan []byte, 1)
+				pool.On(channels[i])
+			}
+
+			g.Assert(len(pool.sinks)).Equal(8)
+
+			pool.Off(channels[2])
+			g.Assert(len(pool.sinks)).Equal(7)
+			g.Assert(pool.sinks[1]).Equal(channels[1])
+			g.Assert(pool.sinks[2]).Equal(channels[3])
+			g.Assert(MutexLocked(&pool.mu)).IsFalse()
+		})
+
+		g.It("does not panic if a nil channel is provided", func() {
+			ch := make([]chan []byte, 1)
+
+			defer func() {
+				if r := recover(); r != nil {
+					g.Fail("removing a nil channel should not cause a panic")
+				}
+			}()
+
+			pool.On(ch[0])
+			pool.Off(ch[0])
+
+			g.Assert(len(pool.sinks)).Equal(0)
+		})
+	})
+
+	g.Describe("SinkPool#Push", func() {
+		var pool *sinkPool
+		g.BeforeEach(func() {
+			pool = &sinkPool{}
+		})
+
+		g.It("works when no sinks are registered", func() {
+			g.Assert(len(pool.sinks)).IsZero()
+			pool.Push([]byte("test"))
+			g.Assert(MutexLocked(&pool.mu)).IsFalse()
+		})
+
+		g.It("sends data to every registered sink", func() {
+			ch1 := make(chan []byte, 1)
+			ch2 := make(chan []byte, 1)
+
+			pool.On(ch1)
+			pool.On(ch2)
+
+			g.Assert(len(pool.sinks)).Equal(2)
+			b := []byte("test")
+			pool.Push(b)
+
+			g.Assert(MutexLocked(&pool.mu)).IsFalse()
+			g.Assert(<-ch1).Equal(b)
+			g.Assert(<-ch2).Equal(b)
+			g.Assert(len(pool.sinks)).Equal(2)
+		})
+
+		g.It("uses a ring-buffer to avoid blocking when the channel is full", func() {
+			ch1 := make(chan []byte, 1)
+			ch2 := make(chan []byte, 2)
+			ch3 := make(chan []byte)
+
+			// ch1 and ch2 are now full, and would block if the code doesn't account
+			// for a full buffer.
+			ch1 <- []byte("pre-test")
+			ch2 <- []byte("pre-test")
+			ch2 <- []byte("pre-test 2")
+
+			pool.On(ch1)
+			pool.On(ch2)
+			pool.On(ch3)
+
+			pool.Push([]byte("testing"))
+			time.Sleep(time.Millisecond * 20)
+
+			g.Assert(MutexLocked(&pool.mu)).IsFalse()
+			// We expect that value previously in the channel to have been dumped
+			// and therefore only the value we pushed will be present. For ch2 we
+			// expect only the first message was dropped, and the second one is now
+			// the first in the out queue.
+			g.Assert(<-ch1).Equal([]byte("testing"))
+			g.Assert(<-ch2).Equal([]byte("pre-test 2"))
+			g.Assert(<-ch2).Equal([]byte("testing"))
+
+			// Because nothing in this test was listening for ch3, it would have
+			// blocked for the 10ms duration, and then been skipped over entirely
+			// because it had no length to try and push onto.
+			g.Assert(len(ch3)).Equal(0)
+
+			// Now, push again and expect similar results.
+			pool.Push([]byte("testing 2"))
+			time.Sleep(time.Millisecond * 20)
+
+			g.Assert(MutexLocked(&pool.mu)).IsFalse()
+			g.Assert(<-ch1).Equal([]byte("testing 2"))
+			g.Assert(<-ch2).Equal([]byte("testing 2"))
+		})
+
+		g.It("can handle concurrent pushes FIFO", func() {
+			ch := make(chan []byte, 4)
+
+			pool.On(ch)
+			pool.On(make(chan []byte))
+
+			for i := 0; i < 100; i++ {
+				pool.Push([]byte(fmt.Sprintf("iteration %d", i)))
+			}
+
+			time.Sleep(time.Millisecond * 20)
+			g.Assert(MutexLocked(&pool.mu)).IsFalse()
+			g.Assert(len(ch)).Equal(4)
+
+			g.Timeout(time.Millisecond * 500)
+			g.Assert(<-ch).Equal([]byte("iteration 96"))
+			g.Assert(<-ch).Equal([]byte("iteration 97"))
+			g.Assert(<-ch).Equal([]byte("iteration 98"))
+			g.Assert(<-ch).Equal([]byte("iteration 99"))
+			g.Assert(len(ch)).Equal(0)
+		})
+	})
+
+	g.Describe("SinkPool#Destroy", func() {
+		var pool *sinkPool
+		g.BeforeEach(func() {
+			pool = &sinkPool{}
+		})
+
+		g.It("works if no sinks are registered", func() {
+			pool.Destroy()
+
+			g.Assert(MutexLocked(&pool.mu)).IsFalse()
+		})
+
+		g.It("closes all channels fully", func() {
+			ch1 := make(chan []byte, 1)
+			ch2 := make(chan []byte, 1)
+
+			pool.On(ch1)
+			pool.On(ch2)
+
+			g.Assert(len(pool.sinks)).Equal(2)
+			pool.Destroy()
+			g.Assert(pool.sinks).IsZero()
+
+			defer func() {
+				r := recover()
+
+				g.Assert(r).IsNotNil()
+				g.Assert(r.(error).Error()).Equal("send on closed channel")
+			}()
+
+			ch1 <- []byte("test")
+		})
+
+		g.It("works when a sink channel is nil", func() {
+			ch := make([]chan []byte, 2)
+
+			pool.On(ch[0])
+			pool.On(ch[1])
+
+			pool.Destroy()
+
+			g.Assert(MutexLocked(&pool.mu)).IsFalse()
+		})
+	})
+}

sftp/handler.go

@@ -119,6 +119,9 @@ func (h *Handler) Filewrite(request *sftp.Request) (io.WriterAt, error) {
 		l.WithField("flags", request.Flags).WithField("error", err).Error("failed to open existing file on system")
 		return nil, sftp.ErrSSHFxFailure
 	}
+	// Chown may or may not have been called in the touch function, so always do
+	// it at this point to avoid the file being improperly owned.
+	_ = h.server.Filesystem().Chown(request.Filepath)
 	return f, nil
 }
 

system/const.go

@@ -1,3 +1,3 @@
 package system
 
-var Version = "develop"
+var Version = "1.6.0"

system/locker.go

@@ -0,0 +1,83 @@
+package system
+
+import (
+	"context"
+	"sync"
+
+	"emperror.dev/errors"
+)
+
+var ErrLockerLocked = errors.Sentinel("locker: cannot acquire lock, already locked")
+
+type Locker struct {
+	mu sync.RWMutex
+	ch chan bool
+}
+
+// NewLocker returns a new Locker instance.
+func NewLocker() *Locker {
+	return &Locker{
+		ch: make(chan bool, 1),
+	}
+}
+
+// IsLocked returns the current state of the locker channel. If there is
+// currently a value in the channel, it is assumed to be locked.
+func (l *Locker) IsLocked() bool {
+	l.mu.RLock()
+	defer l.mu.RUnlock()
+	return len(l.ch) == 1
+}
+
+// Acquire will acquire the power lock if it is not currently locked. If it is
+// already locked, acquire will fail to acquire the lock, and will return false.
+func (l *Locker) Acquire() error {
+	l.mu.Lock()
+	defer l.mu.Unlock()
+	select {
+	case l.ch <- true:
+	default:
+		return ErrLockerLocked
+	}
+	return nil
+}
+
+
+// TryAcquire will attempt to acquire a power-lock until the context provided
+// is canceled.
+func (l *Locker) TryAcquire(ctx context.Context) error {
+	select {
+	case l.ch <- true:
+		return nil
+	case <-ctx.Done():
+		if err := ctx.Err(); err != nil {
+			return err
+		}
+		return nil
+	}
+}
+
+// Release will drain the locker channel so that we can properly re-acquire it
+// at a later time. If the channel is not currently locked this function is a
+// no-op and will immediately return.
+func (l *Locker) Release() {
+	l.mu.Lock()
+	select {
+	case <-l.ch:
+	default:
+	}
+	l.mu.Unlock()
+}
+
+// Destroy cleans up the power locker by closing the channel.
+func (l *Locker) Destroy() {
+	l.mu.Lock()
+	if l.ch != nil {
+		select {
+		case <-l.ch:
+		default:
+		}
+		close(l.ch)
+	}
+	l.mu.Unlock()
+}

system/locker_test.go

@@ -0,0 +1,148 @@
+package system
+
+import (
+	"context"
+	"testing"
+	"time"
+
+	"emperror.dev/errors"
+	. "github.com/franela/goblin"
+)
+
+func TestPower(t *testing.T) {
+	g := Goblin(t)
+
+	g.Describe("Locker", func() {
+		var l *Locker
+		g.BeforeEach(func() {
+			l = NewLocker()
+		})
+
+		g.Describe("PowerLocker#IsLocked", func() {
+			g.It("should return false when the channel is empty", func() {
+				g.Assert(cap(l.ch)).Equal(1)
+				g.Assert(l.IsLocked()).IsFalse()
+			})
+
+			g.It("should return true when the channel is at capacity", func() {
+				l.ch <- true
+
+				g.Assert(l.IsLocked()).IsTrue()
+				<-l.ch
+				g.Assert(l.IsLocked()).IsFalse()
+
+				// We don't care what the channel value is, just that there is
+				// something in it.
+				l.ch <- false
+				g.Assert(l.IsLocked()).IsTrue()
+				g.Assert(cap(l.ch)).Equal(1)
+			})
+		})
+
+		g.Describe("PowerLocker#Acquire", func() {
+			g.It("should acquire a lock when channel is empty", func() {
+				err := l.Acquire()
+
+				g.Assert(err).IsNil()
+				g.Assert(cap(l.ch)).Equal(1)
+				g.Assert(len(l.ch)).Equal(1)
+			})
+
+			g.It("should return an error when the channel is full", func() {
+				l.ch <- true
+
+				err := l.Acquire()
+
+				g.Assert(err).IsNotNil()
+				g.Assert(errors.Is(err, ErrLockerLocked)).IsTrue()
+				g.Assert(cap(l.ch)).Equal(1)
+				g.Assert(len(l.ch)).Equal(1)
+			})
+		})
+
+		g.Describe("PowerLocker#TryAcquire", func() {
+			g.It("should acquire a lock when channel is empty", func() {
+				g.Timeout(time.Second)
+
+				err := l.TryAcquire(context.Background())
+
+				g.Assert(err).IsNil()
+				g.Assert(cap(l.ch)).Equal(1)
+				g.Assert(len(l.ch)).Equal(1)
+				g.Assert(l.IsLocked()).IsTrue()
+			})
+
+			g.It("should block until context is canceled if channel is full", func() {
+				g.Timeout(time.Second)
+				ctx, cancel := context.WithTimeout(context.Background(), time.Millisecond*500)
+				defer cancel()
+
+				l.ch <- true
+				err := l.TryAcquire(ctx)
+
+				g.Assert(err).IsNotNil()
+				g.Assert(errors.Is(err, context.DeadlineExceeded)).IsTrue()
+				g.Assert(cap(l.ch)).Equal(1)
+				g.Assert(len(l.ch)).Equal(1)
+				g.Assert(l.IsLocked()).IsTrue()
+			})
+
+			g.It("should block until lock can be acquired", func() {
+				g.Timeout(time.Second)
+
+				ctx, cancel := context.WithTimeout(context.Background(), time.Millisecond*200)
+				defer cancel()
+
+				l.Acquire()
+				go func() {
+					time.AfterFunc(time.Millisecond * 50, func() {
+						l.Release()
+					})
+				}()
+
+				err := l.TryAcquire(ctx)
+				g.Assert(err).IsNil()
+				g.Assert(cap(l.ch)).Equal(1)
+				g.Assert(len(l.ch)).Equal(1)
+				g.Assert(l.IsLocked()).IsTrue()
+			})
+		})
+
+		g.Describe("PowerLocker#Release", func() {
+			g.It("should release when channel is full", func() {
+				l.Acquire()
+				g.Assert(l.IsLocked()).IsTrue()
+				l.Release()
+				g.Assert(cap(l.ch)).Equal(1)
+				g.Assert(len(l.ch)).Equal(0)
+				g.Assert(l.IsLocked()).IsFalse()
+			})
+
+			g.It("should release when channel is empty", func() {
+				g.Assert(l.IsLocked()).IsFalse()
+				l.Release()
+				g.Assert(cap(l.ch)).Equal(1)
+				g.Assert(len(l.ch)).Equal(0)
+				g.Assert(l.IsLocked()).IsFalse()
+			})
+		})
+
+		g.Describe("PowerLocker#Destroy", func() {
+			g.It("should unlock and close the channel", func() {
+				l.Acquire()
+				g.Assert(l.IsLocked()).IsTrue()
+				l.Destroy()
+				g.Assert(l.IsLocked()).IsFalse()
+
+				defer func() {
+					r := recover()
+
+					g.Assert(r).IsNotNil()
+					g.Assert(r.(error).Error()).Equal("send on closed channel")
+				}()
+
+				l.Acquire()
+			})
+		})
+	})
+}

system/rate.go

@@ -0,0 +1,50 @@
+package system
+
+import (
+	"sync"
+	"time"
+)
+
+// Rate defines a rate limiter of n items (limit) per duration of time.
+type Rate struct {
+	mu       sync.Mutex
+	limit    uint64
+	duration time.Duration
+	count    uint64
+	last     time.Time
+}
+
+func NewRate(limit uint64, duration time.Duration) *Rate {
+	return &Rate{
+		limit:    limit,
+		duration: duration,
+		last:     time.Now(),
+	}
+}
+
+// Try returns true if under the rate limit defined, or false if the rate limit
+// has been exceeded for the current duration.
+func (r *Rate) Try() bool {
+	r.mu.Lock()
+	defer r.mu.Unlock()
+	now := time.Now()
+	// If it has been more than the duration, reset the timer and count.
+	if now.Sub(r.last) > r.duration {
+		r.count = 0
+		r.last = now
+	}
+	if (r.count + 1) > r.limit {
+		return false
+	}
+	// Hit this once, and return.
+	r.count = r.count + 1
+	return true
+}
+
+// Reset resets the internal state of the rate limiter back to zero.
+func (r *Rate) Reset() {
+	r.mu.Lock()
+    r.count = 0
+    r.last = time.Now()
+	r.mu.Unlock()
+}

system/rate_test.go

@@ -0,0 +1,67 @@
+package system
+
+import (
+	"testing"
+	"time"
+
+	. "github.com/franela/goblin"
+)
+
+func TestRate(t *testing.T) {
+	g := Goblin(t)
+
+	g.Describe("Rate", func() {
+		g.It("properly rate limits a bucket", func() {
+			r := NewRate(10, time.Millisecond*100)
+
+			for i := 0; i < 100; i++ {
+				ok := r.Try()
+				if i < 10 && !ok {
+					g.Failf("should not have allowed take on try %d", i)
+				} else if i >= 10 && ok {
+					g.Failf("should have blocked take on try %d", i)
+				}
+			}
+		})
+
+		g.It("handles rate limiting in chunks", func() {
+			var out []int
+			r := NewRate(12, time.Millisecond*10)
+
+			for i := 0; i < 100; i++ {
+				if i%20 == 0 {
+					// Give it time to recover.
+					time.Sleep(time.Millisecond * 10)
+				}
+				if r.Try() {
+					out = append(out, i)
+				}
+			}
+
+			g.Assert(len(out)).Equal(60)
+			g.Assert(out[0]).Equal(0)
+			g.Assert(out[12]).Equal(20)
+			g.Assert(out[len(out)-1]).Equal(91)
+		})
+
+		g.It("resets back to zero when called", func() {
+			r := NewRate(10, time.Second)
+			for i := 0; i < 100; i++ {
+				if i % 10 == 0 {
+					r.Reset()
+				}
+				g.Assert(r.Try()).IsTrue()
+			}
+			g.Assert(r.Try()).IsFalse("final attempt should not allow taking")
+		})
+	})
+}
+
+func BenchmarkRate_Try(b *testing.B) {
+	r := NewRate(10, time.Millisecond*100)
+
+	b.ReportAllocs()
+	for i := 0; i < b.N; i++ {
+		r.Try()
+	}
+}

system/utils.go

@@ -4,7 +4,6 @@ import (
 	"bufio"
 	"bytes"
 	"context"
-	"encoding/json"
 	"fmt"
 	"io"
 	"strconv"
@@ -12,6 +11,7 @@ import (
 	"time"
 
 	"emperror.dev/errors"
+	"github.com/goccy/go-json"
 )
 
 var (
@@ -19,6 +19,11 @@ var (
 	crr = []byte("\r\n")
 )
 
+// The maximum size of the buffer used to send output over the console to
+// clients. Once this length is reached, the line will be truncated and sent
+// as is.
+var maxBufferSize = 64 * 1024
+
 // FirstNotEmpty returns the first string passed in that is not an empty value.
 func FirstNotEmpty(v ...string) string {
 	for _, val := range v {
@@ -37,12 +42,22 @@ func MustInt(v string) int {
 	return i
 }
 
+// ScanReader reads up to 64KB of line from the reader and emits that value
+// over the websocket. If a line exceeds that size, it is truncated and only that
+// amount is sent over.
 func ScanReader(r io.Reader, callback func(line []byte)) error {
-	br := bufio.NewReader(r)
+	// Based on benchmarking this seems to be the best size for the reader buffer
+	// to maintain fast enough workflows without hammering the CPU for allocations.
+	//
+	// Additionally, most games are outputting a high-frequency of smaller lines,
+	// rather than a bunch of massive lines. This allocation amount is the total
+	// number of bytes being output for each call to ReadLine() before it moves on
+	// to the next data pull.
+	br := bufio.NewReaderSize(r, 256)
 	// Avoid constantly re-allocating memory when we're flooding lines through this
 	// function by using the same buffer for the duration of the call and just truncating
 	// the value back to 0 every loop.
-	buf := &bytes.Buffer{}
+	var buf bytes.Buffer
 	for {
 		buf.Reset()
 		var err error
@@ -52,32 +67,54 @@ func ScanReader(r io.Reader, callback func(line []byte)) error {
 		for {
 			// Read the line and write it to the buffer.
 			line, isPrefix, err = br.ReadLine()
+
 			// Certain games like Minecraft output absolutely random carriage returns in the output seemingly
 			// in line with that it thinks is the terminal size. Those returns break a lot of output handling,
 			// so we'll just replace them with proper new-lines and then split it later and send each line as
 			// its own event in the response.
-			buf.Write(bytes.Replace(line, cr, crr, -1))
-			// Finish this loop and begin outputting the line if there is no prefix (the line fit into
-			// the default buffer), or if we hit the end of the line.
+			line = bytes.Replace(line, cr, crr, -1)
+			ns := buf.Len() + len(line)
+
+			// If the length of the line value and the current value in the buffer will
+			// exceed the maximum buffer size, chop it down to hit the maximum size and
+			// then send that data over the socket before ending this loop.
+			//
+			// This ensures that we send as much data as possible, without allowing very
+			// long lines to grow the buffer size excessively and potentially DOS the Wings
+			// instance. If the line is not too long, just store the whole value into the
+			// buffer. This is kind of a re-implementation of the bufio.Scanner.Scan() logic
+			// without triggering an error when you exceed this buffer size.
+			if ns > maxBufferSize {
+				buf.Write(line[:len(line)-(ns-maxBufferSize)])
+				break
+			} else {
+				buf.Write(line)
+			}
+			// Finish this loop and begin outputting the line if there is no prefix
+			// (the line fit into the default buffer), or if we hit the end of the line.
 			if !isPrefix || err == io.EOF {
 				break
 			}
-			// If we encountered an error with something in ReadLine that was not an EOF just abort
-			// the entire process here.
+			// If we encountered an error with something in ReadLine that was not an
+			// EOF just abort the entire process here.
 			if err != nil {
 				return err
 			}
 		}
-		// Ensure that the scanner is always able to read the last line.
-		_, _ = buf.Write([]byte("\r\n"))
-		// Publish the line for this loop. Break on new-line characters so every line is sent as a single
-		// output event, otherwise you get funky handling in the browser console.
-		s := bufio.NewScanner(buf)
-		for s.Scan() {
-			callback(s.Bytes())
+
+		// Send the full buffer length over to the event handler to be emitted in
+		// the websocket. The front-end can handle the linebreaks in the middle of
+		// the output, it simply expects that the end of the event emit is a newline.
+		if buf.Len() > 0 {
+			// You need to make a copy of the buffer here because the callback will encounter
+			// a race condition since "buf.Bytes()" is going to be by-reference if passed directly.
+			c := make([]byte, buf.Len())
+			copy(c, buf.Bytes())
+			callback(c)
 		}
-		// If the error we got previously that lead to the line being output is an io.EOF we want to
-		// exit the entire looping process.
+
+		// If the error we got previously that lead to the line being output is
+		// an io.EOF we want to exit the entire looping process.
 		if err == io.EOF {
 			break
 		}
@@ -128,9 +165,9 @@ func (ab *AtomicBool) Store(v bool) {
 	ab.mu.Unlock()
 }
 
-// Stores the value "v" if the current value stored in the AtomicBool is the opposite
-// boolean value. If successfully swapped, the response is "true", otherwise "false"
-// is returned.
+// SwapIf stores the value "v" if the current value stored in the AtomicBool is
+// the opposite boolean value. If successfully swapped, the response is "true",
+// otherwise "false" is returned.
 func (ab *AtomicBool) SwapIf(v bool) bool {
 	ab.mu.Lock()
 	defer ab.mu.Unlock()

system/utils_test.go

@@ -0,0 +1,135 @@
+package system
+
+import (
+	"math/rand"
+	"strings"
+	"sync"
+	"testing"
+	"time"
+
+	. "github.com/franela/goblin"
+	"github.com/goccy/go-json"
+)
+
+func Test_Utils(t *testing.T) {
+	g := Goblin(t)
+
+	g.Describe("ScanReader", func() {
+		g.BeforeEach(func() {
+			maxBufferSize = 10
+		})
+
+		g.It("should truncate and return long lines", func() {
+			reader := strings.NewReader("hello world this is a long line\nof text that should be truncated\nnot here\nbut definitely on this line")
+
+			var lines []string
+			err := ScanReader(reader, func(line []byte) {
+				lines = append(lines, string(line))
+			})
+
+			g.Assert(err).IsNil()
+			g.Assert(lines).Equal([]string{"hello worl", "of text th", "not here", "but defini"})
+		})
+
+		g.It("should replace cariage returns with newlines", func() {
+			reader := strings.NewReader("test\rstring\r\nanother\rline\nhodor\r\r\rheld the door\nmaterial gourl\n")
+			var lines []string
+			err := ScanReader(reader, func(line []byte) {
+				lines = append(lines, string(line))
+			})
+
+			g.Assert(err).IsNil()
+			g.Assert(lines).Equal([]string{"test\rstrin", "another\rli", "hodor\r\r\rhe", "material g"})
+		})
+	})
+
+	g.Describe("AtomicBool", func() {
+		var b *AtomicBool
+		g.BeforeEach(func() {
+			b = NewAtomicBool(false)
+		})
+
+		g.It("initalizes with the provided start value", func() {
+			b = NewAtomicBool(true)
+			g.Assert(b.Load()).IsTrue()
+
+			b = NewAtomicBool(false)
+			g.Assert(b.Load()).IsFalse()
+		})
+
+		g.Describe("AtomicBool#Store", func() {
+			g.It("stores the provided value", func() {
+				g.Assert(b.Load()).IsFalse()
+				b.Store(true)
+				g.Assert(b.Load()).IsTrue()
+			})
+
+			// This test makes no assertions, it just expects to not hit a race condition
+			// by having multiple things writing at the same time.
+			g.It("handles contention from multiple routines", func() {
+				var wg sync.WaitGroup
+
+				wg.Add(100)
+				for i := 0; i < 100; i++ {
+					go func(i int) {
+						b.Store(i%2 == 0)
+						wg.Done()
+					}(i)
+				}
+				wg.Wait()
+			})
+		})
+
+		g.Describe("AtomicBool#SwapIf", func() {
+			g.It("swaps the value out if different than what is stored", func() {
+				o := b.SwapIf(false)
+				g.Assert(o).IsFalse()
+				g.Assert(b.Load()).IsFalse()
+
+				o = b.SwapIf(true)
+				g.Assert(o).IsTrue()
+				g.Assert(b.Load()).IsTrue()
+
+				o = b.SwapIf(true)
+				g.Assert(o).IsFalse()
+				g.Assert(b.Load()).IsTrue()
+
+				o = b.SwapIf(false)
+				g.Assert(o).IsTrue()
+				g.Assert(b.Load()).IsFalse()
+			})
+		})
+
+		g.Describe("can be marshaled with JSON", func() {
+			type testStruct struct {
+				Value AtomicBool `json:"value"`
+			}
+
+			var o testStruct
+			err := json.Unmarshal([]byte(`{"value":true}`), &o)
+
+			g.Assert(err).IsNil()
+			g.Assert(o.Value.Load()).IsTrue()
+
+			b, err2 := json.Marshal(&o)
+			g.Assert(err2).IsNil()
+			g.Assert(b).Equal([]byte(`{"value":true}`))
+		})
+	})
+}
+
+func Benchmark_ScanReader(b *testing.B) {
+	r := rand.New(rand.NewSource(time.Now().UnixNano()))
+	var str string
+	for i := 0; i < 10; i++ {
+		str += strings.Repeat("hello \rworld", r.Intn(2000)) + "\n"
+	}
+	reader := strings.NewReader(str)
+
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		_ = ScanReader(reader, func(line []byte) {
+			// no op
+		})
+	}
+}