Get working console websocket implementation and fix race condition

server/environment_docker.go

@@ -228,7 +228,7 @@ func (d *DockerEnvironment) FollowConsoleOutput() error {
 
 		s := bufio.NewScanner(r)
 		for s.Scan() {
-			fmt.Println(s.Text())
+			d.Server.Emit(ConsoleOutputEvent, s.Text())
 		}
 
 		if err := s.Err(); err != nil {

server/events.go

@@ -0,0 +1,46 @@
+package server
+
+type EventListeners map[string][]EventListenerFunction
+
+type EventListenerFunction *func(string)
+
+// Defines all of the possible output events for a server.
+const (
+	ConsoleOutputEvent = "console"
+)
+
+// Adds an event listener for the server instance.
+func (s *Server) AddListener(event string, f EventListenerFunction) {
+	if s.listeners == nil {
+		s.listeners = make(map[string][]EventListenerFunction)
+	}
+
+	if _, ok := s.listeners[event]; ok {
+		s.listeners[event] = append(s.listeners[event], f)
+	} else {
+		s.listeners[event] = []EventListenerFunction{f}
+	}
+}
+
+// Removes the event listener for the server instance.
+func (s *Server) RemoveListener(event string, f EventListenerFunction) {
+	if _, ok := s.listeners[event]; ok {
+		for i := range s.listeners[event] {
+			if s.listeners[event][i] == f {
+				s.listeners[event] = append(s.listeners[event][:i], s.listeners[event][i+1:]...)
+				break
+			}
+		}
+	}
+}
+
+// Emits an event to all of the active listeners for a server.
+func (s *Server) Emit(event string, data string) {
+	if _, ok := s.listeners[event]; ok {
+		for _, handler := range s.listeners[event] {
+			go func (f EventListenerFunction, d string) {
+				(*f)(d)
+			}(handler, data)
+		}
+	}
+}

server/server.go

@@ -1,7 +1,6 @@
 package server
 
 import (
-	"github.com/olebedev/emitter"
 	"github.com/patrickmn/go-cache"
 	"github.com/pkg/errors"
 	"github.com/pterodactyl/wings/config"
@@ -62,7 +61,8 @@ type Server struct {
 	// certain long operations return faster. For example, FS disk space usage.
 	Cache *cache.Cache `json:"-"`
 
-	Emitter *emitter.Emitter `json:"-"`
+	// All of the registered event listeners for this server instance.
+	listeners EventListeners
 }
 
 // The build settings for a given server that impact docker container creation and
@@ -206,7 +206,6 @@ func FromConfiguration(data []byte, cfg *config.SystemConfiguration) (*Server, e
 		return nil, err
 	}
 
-	s.Emitter = &emitter.Emitter{}
 	s.Environment = env
 	s.Cache = cache.New(time.Minute * 10, time.Minute * 15)
 	s.Filesystem = &Filesystem{