Server Event Optimizations (#116)

router/websocket/listeners.go

@@ -2,6 +2,7 @@ package websocket
 
 import (
 	"context"
+	"encoding/json"
 	"sync"
 	"time"
 
@@ -53,9 +54,9 @@ func (h *Handler) listenForExpiration(ctx context.Context) {
 			jwt := h.GetJwt()
 			if jwt != nil {
 				if jwt.ExpirationTime.Unix()-time.Now().Unix() <= 0 {
-					_ = h.SendJson(&Message{Event: TokenExpiredEvent})
+					_ = h.SendJson(Message{Event: TokenExpiredEvent})
 				} else if jwt.ExpirationTime.Unix()-time.Now().Unix() <= 60 {
-					_ = h.SendJson(&Message{Event: TokenExpiringEvent})
+					_ = h.SendJson(Message{Event: TokenExpiringEvent})
 				}
 			}
 		}
@@ -79,38 +80,79 @@ var e = []string{
 // ListenForServerEvents will listen for different events happening on a server
 // and send them along to the connected websocket client. This function will
 // block until the context provided to it is canceled.
-func (h *Handler) listenForServerEvents(pctx context.Context) error {
+func (h *Handler) listenForServerEvents(ctx context.Context) error {
 	var o sync.Once
 	var err error
-	ctx, cancel := context.WithCancel(pctx)
 
-	callback := func(e events.Event) {
-		if sendErr := h.SendJson(&Message{Event: e.Topic, Args: []string{e.Data}}); sendErr != nil {
-			h.Logger().WithField("event", e.Topic).WithField("error", sendErr).Error("failed to send event over server websocket")
-			// Avoid race conditions by only setting the error once and then canceling
-			// the context. This way if additional processing errors come through due
-			// to a massive flood of things you still only report and stop at the first.
-			o.Do(func() {
-				err = sendErr
-				cancel()
-			})
-		}
+	ctx, cancel := context.WithCancel(ctx)
+	defer cancel()
+
+	eventChan := make(chan events.Event)
+	logOutput := make(chan []byte)
+	installOutput := make(chan []byte)
+	h.server.Events().On(eventChan, e...)
+	h.server.LogSink().On(logOutput)
+	h.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")
+		// Avoid race conditions by only setting the error once and then canceling
+		// the context. This way if additional processing errors come through due
+		// to a massive flood of things you still only report and stop at the first.
+		o.Do(func() {
+			err = err2
+		})
+		cancel()
 	}
 
-	// Subscribe to all of the events with the same callback that will push the
-	// data out over the websocket for the server.
-	for _, evt := range e {
-		h.server.Events().On(evt, &callback)
+	for {
+		select {
+		case <-ctx.Done():
+			break
+		case e := <-logOutput:
+			sendErr := h.SendJson(Message{Event: server.ConsoleOutputEvent, Args: []string{string(e)}})
+			if sendErr == nil {
+				continue
+			}
+			onError(server.ConsoleOutputEvent, sendErr)
+		case e := <-installOutput:
+			sendErr := h.SendJson(Message{Event: server.InstallOutputEvent, Args: []string{string(e)}})
+			if sendErr == nil {
+				continue
+			}
+			onError(server.InstallOutputEvent, sendErr)
+		case e := <-eventChan:
+			var sendErr error
+			message := Message{Event: e.Topic}
+			if str, ok := e.Data.(string); ok {
+				message.Args = []string{str}
+			} else if b, ok := e.Data.([]byte); ok {
+				message.Args = []string{string(b)}
+			} else {
+				b, sendErr = json.Marshal(e.Data)
+				if sendErr == nil {
+					message.Args = []string{string(b)}
+				}
+			}
+
+			if sendErr == nil {
+				sendErr = h.SendJson(message)
+				if sendErr == nil {
+					continue
+				}
+			}
+			onError(message.Event, sendErr)
+		}
+		break
 	}
 
-	// When this function returns de-register all of the event listeners.
-	defer func() {
-		for _, evt := range e {
-			h.server.Events().Off(evt, &callback)
-		}
-	}()
+	h.server.Events().Off(eventChan, e...)
+	h.server.InstallSink().Off(logOutput)
+	h.server.InstallSink().Off(installOutput)
+	close(eventChan)
+	close(logOutput)
+	close(installOutput)
 
-	<-ctx.Done()
 	// 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
 	// we can assume the parent was canceled and need not perform any actions.

router/websocket/websocket.go

@@ -122,18 +122,17 @@ func (h *Handler) Logger() *log.Entry {
 		WithField("server", h.server.ID())
 }
 
-func (h *Handler) SendJson(v *Message) error {
+func (h *Handler) SendJson(v Message) error {
 	// Do not send JSON down the line if the JWT on the connection is not valid!
 	if err := h.TokenValid(); err != nil {
-		h.unsafeSendJson(Message{
+		_ = h.unsafeSendJson(Message{
 			Event: JwtErrorEvent,
 			Args:  []string{err.Error()},
 		})
 		return nil
 	}
 
-	j := h.GetJwt()
-	if j != nil {
+	if j := h.GetJwt(); j != nil {
 		// If we're sending installation output but the user does not have the required
 		// permissions to see the output, don't send it down the line.
 		if v.Event == server.InstallOutputEvent {
@@ -297,7 +296,7 @@ func (h *Handler) HandleInbound(ctx context.Context, m Message) error {
 			h.setJwt(token)
 
 			// Tell the client they authenticated successfully.
-			h.unsafeSendJson(Message{Event: AuthenticationSuccessEvent})
+			_ = h.unsafeSendJson(Message{Event: AuthenticationSuccessEvent})
 
 			// Check if the client was refreshing their authentication token
 			// instead of authenticating for the first time.
@@ -315,7 +314,7 @@ func (h *Handler) HandleInbound(ctx context.Context, m Message) error {
 			// On every authentication event, send the current server status back
 			// to the client. :)
 			state := h.server.Environment.State()
-			h.SendJson(&Message{
+			_ = h.SendJson(Message{
 				Event: server.StatusEvent,
 				Args:  []string{state},
 			})
@@ -327,7 +326,7 @@ func (h *Handler) HandleInbound(ctx context.Context, m Message) error {
 					_ = h.server.Filesystem().HasSpaceAvailable(false)
 
 					b, _ := json.Marshal(h.server.Proc())
-					h.SendJson(&Message{
+					_ = h.SendJson(Message{
 						Event: server.StatsEvent,
 						Args:  []string{string(b)},
 					})
@@ -357,7 +356,7 @@ func (h *Handler) HandleInbound(ctx context.Context, m Message) error {
 			if errors.Is(err, context.DeadlineExceeded) {
 				m, _ := h.GetErrorMessage("another power action is currently being processed for this server, please try again later")
 
-				h.SendJson(&Message{
+				_ = h.SendJson(Message{
 					Event: ErrorEvent,
 					Args:  []string{m},
 				})
@@ -381,7 +380,7 @@ func (h *Handler) HandleInbound(ctx context.Context, m Message) error {
 			}
 
 			for _, line := range logs {
-				h.SendJson(&Message{
+				_ = h.SendJson(Message{
 					Event: server.ConsoleOutputEvent,
 					Args:  []string{line},
 				})
@@ -392,7 +391,7 @@ func (h *Handler) HandleInbound(ctx context.Context, m Message) error {
 	case SendStatsEvent:
 		{
 			b, _ := json.Marshal(h.server.Proc())
-			h.SendJson(&Message{
+			_ = h.SendJson(Message{
 				Event: server.StatsEvent,
 				Args:  []string{string(b)},
 			})