wsutil: Added graceful close checking

* Gateway: use gateway version 8

* API: remove old v0.0.1 version tag

* Discord: fix typos

* Gateway: add timeout

* Gateway: revert to returning errors on ReconnectCtx

api/api.go

@@ -21,7 +21,7 @@ var (
 	EndpointGatewayBot = EndpointGateway + "/bot"
 )
 
-var UserAgent = "DiscordBot (https://github.com/diamondburned/arikawa/v2, v0.0.1)"
+var UserAgent = "DiscordBot (https://github.com/diamondburned/arikawa/v2)"
 
 type Client struct {
 	*httputil.Client

discord/channel.go

@@ -128,7 +128,7 @@ const (
 	OverwriteMember
 )
 
-// UnmarshalJSON unmarshals both a string-quoteed number and a regular number
+// UnmarshalJSON unmarshalls both a string-quoted number and a regular number
 // into OverwriteType. We need to do this because Discord is so bad that they
 // can't even handle 1s and 0s properly.
 func (otype *OverwriteType) UnmarshalJSON(b []byte) error {

gateway/gateway.go

@@ -26,9 +26,8 @@ var (
 	EndpointGateway    = api.Endpoint + "gateway"
 	EndpointGatewayBot = api.EndpointGateway + "/bot"
 
-	Version  = "6"
+	Version  = api.Version
 	Encoding = "json"
-	// Compress = "zlib-stream"
 )
 
 var (
@@ -79,6 +78,13 @@ func BotURL(token string) (*BotData, error) {
 type Gateway struct {
 	WS        *wsutil.Websocket
 	WSTimeout time.Duration
+	// ReconnectTimeout is the timeout used during reconnection.
+	// If the a connection to the gateway can't be established before the
+	// duration passes, the Gateway will be closed and FatalErrorCallback will
+	// be called.
+	//
+	// Setting this to 0 is equivalent to no timeout.
+	ReconnectTimeout time.Duration
 
 	// All events sent over are pointers to Event structs (structs suffixed with
 	// "Event"). This shouldn't be accessed if the Gateway is created with a
@@ -95,14 +101,23 @@ type Gateway struct {
 	PacerLoop wsutil.PacemakerLoop
 
 	ErrorLog func(err error) // default to log.Println
+	// FatalErrorCallback is called, if the Gateway exits fatally. At the point
+	// of calling, the gateway will be already closed.
+	//
+	// Currently this will only be called, if the ReconnectTimeout was changed
+	// to a definite timeout, and connection could not be established during
+	// that time.
+	// err will be ErrWSMaxTries in that case.
+	//
+	// Defaults to noop.
+	FatalErrorCallback func(err error)
 
 	// AfterClose is called after each close. Error can be non-nil, as this is
 	// called even when the Gateway is gracefully closed. It's used mainly for
 	// reconnections or any type of connection interruptions.
 	AfterClose func(err error) // noop by default
 
-	// Filled by methods, internal use
-	waitGroup *sync.WaitGroup
+	waitGroup sync.WaitGroup
 }
 
 // NewGatewayWithIntents creates a new Gateway with the given intents and the
@@ -161,55 +176,48 @@ func (g *Gateway) AddIntents(i Intents) {
 }
 
 // Close closes the underlying Websocket connection.
-func (g *Gateway) Close() (err error) {
-	wsutil.WSDebug("Trying to close.")
+func (g *Gateway) Close() error {
+	wsutil.WSDebug("Trying to close. Pacemaker check skipped.")
 
-	// Check if the WS is already closed:
-	if g.PacerLoop.Stopped() {
-		wsutil.WSDebug("Gateway is already closed.")
-		return err
+	wsutil.WSDebug("Closing the Websocket...")
+	err := g.WS.Close()
+
+	if errors.Is(err, wsutil.ErrWebsocketClosed) {
+		wsutil.WSDebug("Websocket already closed.")
+		return nil
 	}
 
-	// Trigger the close callback on exit.
-	defer func() { g.AfterClose(err) }()
+	wsutil.WSDebug("Websocket closed; error:", err)
 
-	// If the pacemaker is running:
-	if !g.PacerLoop.Stopped() {
-		wsutil.WSDebug("Stopping pacemaker...")
-
-		// Stop the pacemaker and the event handler.
-		g.PacerLoop.Stop()
-
-		wsutil.WSDebug("Stopped pacemaker.")
-	}
-
-	wsutil.WSDebug("Closing the websocket...")
-	err = g.WS.Close()
-
-	wsutil.WSDebug("Waiting for WaitGroup to be done.")
-
-	// This should work, since Pacemaker should signal its loop to stop, which
-	// would also exit our event loop. Both would be 2.
+	wsutil.WSDebug("Waiting for the Pacemaker loop to exit.")
 	g.waitGroup.Wait()
+	wsutil.WSDebug("Pacemaker loop exited.")
+
+	g.AfterClose(err)
+	wsutil.WSDebug("AfterClose callback finished.")
 
-	wsutil.WSDebug("WaitGroup is done. Closing the websocket.")
 	return err
 }
 
-// Reconnect tries to reconnect forever. It will resume the connection if
-// possible. If an Invalid Session is received, it will start a fresh one.
+// Reconnect tries to reconnect until the ReconnectTimeout is reached, or if
+// set to 0 reconnects indefinitely.
 func (g *Gateway) Reconnect() {
-	for {
-		if err := g.ReconnectCtx(context.Background()); err != nil {
-			g.ErrorLog(err)
-		} else {
-			return
-		}
+	ctx := context.Background()
+
+	if g.ReconnectTimeout > 0 {
+		var cancel func()
+		ctx, cancel = context.WithTimeout(context.Background(), g.WSTimeout)
+
+		defer cancel()
 	}
+
+	// ignore the error, it is already logged and FatalErrorCallback was called
+	g.ReconnectCtx(ctx)
 }
 
-// ReconnectCtx attempts to reconnect until context expires. If context cannot
-// expire, then the gateway will try to reconnect forever.
+// ReconnectCtx attempts to reconnect until context expires.
+// If the context expires FatalErrorCallback will be called with ErrWSMaxTries,
+// and the last error returned by Open will be returned.
 func (g *Gateway) ReconnectCtx(ctx context.Context) (err error) {
 	wsutil.WSDebug("Reconnecting...")
 
@@ -220,6 +228,7 @@ func (g *Gateway) ReconnectCtx(ctx context.Context) (err error) {
 	for i := 1; ; i++ {
 		select {
 		case <-ctx.Done():
+			g.FatalErrorCallback(ErrWSMaxTries)
 			return err
 		default:
 		}
@@ -301,9 +310,6 @@ func (g *Gateway) start(ctx context.Context) error {
 	// This is where we'll get our events
 	ch := g.WS.Listen()
 
-	// Make a new WaitGroup for use in background loops:
-	g.waitGroup = new(sync.WaitGroup)
-
 	// Create a new Hello event and wait for it.
 	var hello HelloEvent
 	// Wait for an OP 10 Hello.

gateway/integration_test.go

@@ -49,7 +49,7 @@ func TestIntegration(t *testing.T) {
 	}
 
 	wsutil.WSError = func(err error) {
-		t.Fatal(err)
+		t.Error(err)
 	}
 
 	var gateway *Gateway
@@ -59,6 +59,7 @@ func TestIntegration(t *testing.T) {
 	if err != nil {
 		t.Fatal("Failed to make a Gateway:", err)
 	}
+	g.AddIntents(IntentGuilds)
 	g.AfterClose = func(err error) {
 		log.Println("Closed.")
 	}

internal/heart/heart.go

@@ -81,7 +81,7 @@ func (p *Pacemaker) Dead() bool {
 }
 
 // Stop stops the pacemaker, or it does nothing if the pacemaker is not started.
-func (p *Pacemaker) Stop() {
+func (p *Pacemaker) StopTicker() {
 	p.ticker.Stop()
 }
 
@@ -106,60 +106,3 @@ func (p *Pacemaker) PaceCtx(ctx context.Context) error {
 
 	return nil
 }
-
-// func (p *Pacemaker) start() error {
-// 	// Reset states to its old position.
-// 	p.EchoBeat.Set(time.Time{})
-// 	p.SentBeat.Set(time.Time{})
-
-// 	// Create a new ticker.
-// 	tick := time.NewTicker(p.Heartrate)
-// 	defer tick.Stop()
-
-// 	// Echo at least once
-// 	p.Echo()
-
-// 	for {
-// 		if err := p.pace(); err != nil {
-// 			return errors.Wrap(err, "failed to pace")
-// 		}
-
-// 		// Paced, save:
-// 		p.SentBeat.Set(time.Now())
-
-// 		if p.Dead() {
-// 			return ErrDead
-// 		}
-
-// 		select {
-// 		case <-p.stop:
-// 			return nil
-
-// 		case <-tick.C:
-// 		}
-// 	}
-// }
-
-// // StartAsync starts the pacemaker asynchronously. The WaitGroup is optional.
-// func (p *Pacemaker) StartAsync(wg *sync.WaitGroup) (death chan error) {
-// 	p.death = make(chan error)
-// 	p.stop = make(chan struct{})
-// 	p.once = sync.Once{}
-
-// 	if wg != nil {
-// 		wg.Add(1)
-// 	}
-
-// 	go func() {
-// 		p.death <- p.start()
-// 		// Debug.
-// 		Debug("Pacemaker returned.")
-
-// 		// Mark the pacemaker loop as done.
-// 		if wg != nil {
-// 			wg.Done()
-// 		}
-// 	}()
-
-// 	return p.death
-// }

utils/wsutil/conn.go

@@ -6,6 +6,7 @@ import (
 	"context"
 	"io"
 	"net/http"
+	"strings"
 	"time"
 
 	"github.com/gorilla/websocket"
@@ -52,7 +53,8 @@ type Connection interface {
 // Conn is the default Websocket connection. It tries to compresses all payloads
 // using zlib.
 type Conn struct {
-	Dialer *websocket.Dialer
+	Dialer websocket.Dialer
+	Header http.Header
 	Conn   *websocket.Conn
 	events chan Event
 }
@@ -61,7 +63,7 @@ var _ Connection = (*Conn)(nil)
 
 // NewConn creates a new default websocket connection with a default dialer.
 func NewConn() *Conn {
-	return NewConnWithDialer(&websocket.Dialer{
+	return NewConnWithDialer(websocket.Dialer{
 		Proxy:             http.ProxyFromEnvironment,
 		HandshakeTimeout:  WSTimeout,
 		ReadBufferSize:    CopyBufferSize,
@@ -71,20 +73,20 @@ func NewConn() *Conn {
 }
 
 // NewConn creates a new default websocket connection with a custom dialer.
-func NewConnWithDialer(dialer *websocket.Dialer) *Conn {
-	return &Conn{Dialer: dialer}
+func NewConnWithDialer(dialer websocket.Dialer) *Conn {
+	return &Conn{
+		Dialer: dialer,
+		Header: http.Header{
+			"Accept-Encoding": {"zlib"},
+		},
+	}
 }
 
 func (c *Conn) Dial(ctx context.Context, addr string) (err error) {
 	// BUG which prevents stream compression.
 	// See https://github.com/golang/go/issues/31514.
 
-	// Enable compression:
-	headers := http.Header{
-		"Accept-Encoding": {"zlib"},
-	}
-
-	c.Conn, _, err = c.Dialer.DialContext(ctx, addr, headers)
+	c.Conn, _, err = c.Dialer.DialContext(ctx, addr, c.Header)
 	if err != nil {
 		return errors.Wrap(err, "failed to dial WS")
 	}
@@ -120,6 +122,10 @@ func (c *Conn) Send(ctx context.Context, b []byte) error {
 }
 
 func (c *Conn) Close() error {
+	// Have a deadline before closing.
+	var deadline = time.Now().Add(5 * time.Second)
+	c.Conn.SetWriteDeadline(deadline)
+
 	// Close the WS.
 	err := c.Conn.Close()
 
@@ -162,6 +168,12 @@ func startReadLoop(conn *websocket.Conn, eventCh chan<- Event) {
 				return
 			}
 
+			// Is the error an intentional close call? Go 1.16 exposes
+			// ErrClosing, but we have to do this for now.
+			if strings.HasSuffix(err.Error(), "use of closed network connection") {
+				return
+			}
+
 			// Check if the error is a normal one:
 			if websocket.IsCloseError(err, websocket.CloseNormalClosure) {
 				return

utils/wsutil/heart.go

@@ -2,13 +2,11 @@ package wsutil
 
 import (
 	"context"
-	"runtime/debug"
 	"time"
 
 	"github.com/pkg/errors"
 
 	"github.com/diamondburned/arikawa/v2/internal/heart"
-	"github.com/diamondburned/arikawa/v2/internal/moreatomic"
 )
 
 type errBrokenConnection struct {
@@ -49,17 +47,11 @@ type EventLoopHandler interface {
 // is a valid instance only when RunAsync is called first.
 type PacemakerLoop struct {
 	heart.Pacemaker
-	running moreatomic.Bool
+	Extras   ExtraHandlers
+	ErrorLog func(error)
 
-	stop    chan struct{}
 	events  <-chan Event
 	handler func(*OP) error
-
-	stack []byte
-
-	Extras ExtraHandlers
-
-	ErrorLog func(error)
 }
 
 func (p *PacemakerLoop) errorLog(err error) {
@@ -76,22 +68,6 @@ func (p *PacemakerLoop) Pace(ctx context.Context) error {
 	return p.Pacemaker.PaceCtx(ctx)
 }
 
-// Stop stops the pacer loop. It does nothing if the loop is already stopped.
-func (p *PacemakerLoop) Stop() {
-	if p.Stopped() {
-		return
-	}
-
-	// Despite p.running and p.stop being thread-safe on their own, this entire
-	// block is actually not thread-safe.
-	p.Pacemaker.Stop()
-	close(p.stop)
-}
-
-func (p *PacemakerLoop) Stopped() bool {
-	return p == nil || !p.running.Get()
-}
-
 func (p *PacemakerLoop) RunAsync(
 	heartrate time.Duration, evs <-chan Event, evl EventLoopHandler, exit func(error)) {
 
@@ -100,27 +76,16 @@ func (p *PacemakerLoop) RunAsync(
 	p.Pacemaker = heart.NewPacemaker(heartrate, evl.HeartbeatCtx)
 	p.handler = evl.HandleOP
 	p.events = evs
-	p.stack = debug.Stack()
-	p.stop = make(chan struct{})
 
-	p.running.Set(true)
-
-	go func() {
-		exit(p.startLoop())
-	}()
+	go func() { exit(p.startLoop()) }()
 }
 
 func (p *PacemakerLoop) startLoop() error {
 	defer WSDebug("Pacemaker loop has exited.")
-	defer p.running.Set(false)
-	defer p.Pacemaker.Stop()
+	defer p.Pacemaker.StopTicker()
 
 	for {
 		select {
-		case <-p.stop:
-			WSDebug("Stop requested; exiting.")
-			return nil
-
 		case <-p.Pacemaker.Ticks:
 			if err := p.Pacemaker.Pace(); err != nil {
 				return errors.Wrap(err, "pace failed, reconnecting")

utils/wsutil/ws.go

@@ -144,7 +144,7 @@ func (ws *Websocket) SendCtx(ctx context.Context, b []byte) error {
 
 // Close closes the websocket connection. It assumes that the Websocket is
 // closed even when it returns an error. If the Websocket was already closed
-// before, nil will be returned.
+// before, ErrWebsocketClosed will be returned.
 func (ws *Websocket) Close() error {
 	WSDebug("Conn: Acquiring mutex lock to close...")
 
@@ -160,7 +160,7 @@ func (ws *Websocket) Close() error {
 // more information.
 func (ws *Websocket) close() error {
 	if ws.closed {
-		return nil
+		return ErrWebsocketClosed
 	}
 
 	err := ws.conn.Close()

voice/voicegateway/gateway.go

@@ -99,7 +99,7 @@ func (c *Gateway) OpenCtx(ctx context.Context) error {
 	// https://discordapp.com/developers/docs/topics/voice-connections#establishing-a-voice-websocket-connection
 	var endpoint = "wss://" + strings.TrimSuffix(c.state.Endpoint, ":80") + "/?v=" + Version
 
-	wsutil.WSDebug("Connecting to voice endpoint (endpoint=" + endpoint + ")")
+	wsutil.WSDebug("VoiceGateway: Connecting to voice endpoint (endpoint=" + endpoint + ")")
 
 	// Create a new context with a timeout for the connection.
 	ctx, cancel := context.WithTimeout(ctx, c.Timeout)
@@ -110,7 +110,7 @@ func (c *Gateway) OpenCtx(ctx context.Context) error {
 		return errors.Wrap(err, "failed to connect to voice gateway")
 	}
 
-	wsutil.WSDebug("Trying to start...")
+	wsutil.WSDebug("VoiceGateway: Trying to start...")
 
 	// Try to start or resume the connection.
 	if err := c.start(ctx); err != nil {
@@ -123,12 +123,12 @@ func (c *Gateway) OpenCtx(ctx context.Context) error {
 // Start .
 func (c *Gateway) start(ctx context.Context) error {
 	if err := c.__start(ctx); err != nil {
-		wsutil.WSDebug("Start failed: ", err)
+		wsutil.WSDebug("VoiceGateway: Start failed: ", err)
 
 		// Close can be called with the mutex still acquired here, as the
 		// pacemaker hasn't started yet.
 		if err := c.Close(); err != nil {
-			wsutil.WSDebug("Failed to close after start fail: ", err)
+			wsutil.WSDebug("VoiceGateway: Failed to close after start fail: ", err)
 		}
 		return err
 	}
@@ -144,7 +144,7 @@ func (c *Gateway) __start(ctx context.Context) error {
 	ch := c.WS.Listen()
 
 	// Wait for hello.
-	wsutil.WSDebug("Waiting for Hello..")
+	wsutil.WSDebug("VoiceGateway: Waiting for Hello..")
 
 	var hello *HelloEvent
 	// Wait for the Hello event; return if it times out.
@@ -160,7 +160,7 @@ func (c *Gateway) __start(ctx context.Context) error {
 		return errors.Wrap(ctx.Err(), "failed to wait for Hello event")
 	}
 
-	wsutil.WSDebug("Received Hello")
+	wsutil.WSDebug("VoiceGateway: Received Hello")
 
 	// https://discordapp.com/developers/docs/topics/voice-connections#establishing-a-voice-websocket-connection
 	// Turns out Hello is sent right away on connection start.
@@ -189,7 +189,7 @@ func (c *Gateway) __start(ctx context.Context) error {
 
 	c.EventLoop.RunAsync(hello.HeartbeatInterval.Duration(), ch, c, func(err error) {
 		c.waitGroup.Done() // mark so Close() can exit.
-		wsutil.WSDebug("Event loop stopped.")
+		wsutil.WSDebug("VoiceGateway: Event loop stopped.")
 
 		if err != nil {
 			c.ErrorLog(err)
@@ -202,44 +202,32 @@ func (c *Gateway) __start(ctx context.Context) error {
 		}
 	})
 
-	wsutil.WSDebug("Started successfully.")
+	wsutil.WSDebug("VoiceGateway: Started successfully.")
 
 	return nil
 }
 
-// Close .
-func (c *Gateway) Close() (err error) {
-	wsutil.WSDebug("Trying to close.")
+// Close closes the underlying Websocket connection.
+func (g *Gateway) Close() error {
+	wsutil.WSDebug("VoiceGateway: Trying to close. Pacemaker check skipped.")
 
-	// Check if the WS is already closed:
-	if c.EventLoop.Stopped() {
-		wsutil.WSDebug("Gateway is already closed.")
-		return err
+	wsutil.WSDebug("VoiceGateway: Closing the Websocket...")
+	err := g.WS.Close()
+
+	if errors.Is(err, wsutil.ErrWebsocketClosed) {
+		wsutil.WSDebug("VoiceGateway: Websocket already closed.")
+		return nil
 	}
 
-	// Trigger the close callback on exit.
-	defer func() { c.AfterClose(err) }()
+	wsutil.WSDebug("VoiceGateway: Websocket closed; error:", err)
 
-	// If the pacemaker is running:
-	if !c.EventLoop.Stopped() {
-		wsutil.WSDebug("Stopping pacemaker...")
+	wsutil.WSDebug("VoiceGateway: Waiting for the Pacemaker loop to exit.")
+	g.waitGroup.Wait()
+	wsutil.WSDebug("VoiceGateway: Pacemaker loop exited.")
 
-		// Stop the pacemaker and the event handler.
-		c.EventLoop.Stop()
+	g.AfterClose(err)
+	wsutil.WSDebug("VoiceGateway: AfterClose callback finished.")
 
-		wsutil.WSDebug("Stopped pacemaker.")
-	}
-
-	wsutil.WSDebug("Closing the websocket...")
-	err = c.WS.Close()
-
-	wsutil.WSDebug("Waiting for WaitGroup to be done.")
-
-	// This should work, since Pacemaker should signal its loop to stop, which
-	// would also exit our event loop. Both would be 2.
-	c.waitGroup.Wait()
-
-	wsutil.WSDebug("WaitGroup is done. Closing the websocket.")
 	return err
 }
 
@@ -248,7 +236,7 @@ func (c *Gateway) Reconnect() error {
 }
 
 func (c *Gateway) ReconnectCtx(ctx context.Context) error {
-	wsutil.WSDebug("Reconnecting...")
+	wsutil.WSDebug("VoiceGateway: Reconnecting...")
 
 	// TODO: implement a reconnect loop
 
@@ -266,7 +254,7 @@ func (c *Gateway) ReconnectCtx(ctx context.Context) error {
 		return errors.Wrap(err, "failed to reopen gateway")
 	}
 
-	wsutil.WSDebug("Reconnected successfully.")
+	wsutil.WSDebug("VoiceGateway: Reconnected successfully.")
 
 	return nil
 }