fix: Close conn if context deadline is exceeded (#395)

kylecarbs · web-flow · commit 53e7c3312ade · 2021-07-21T18:33:37.000-06:00
* fix: Close conn if context deadline is exceeded

Previously the error occurred but never propogated due to blocking fromm
the read loop in negotiate. Now, connection timeouts can properly occur.

* Fixes
diff --git a/wsnet/dial.go b/wsnet/dial.go
@@ -147,14 +147,16 @@ func (d *Dialer) negotiate(ctx context.Context) (err error) {
 		// so it's better to buffer and process than fail.
 		pendingCandidates = []webrtc.ICECandidateInit{}
 	)
-
 	go func() {
 		defer close(errCh)
 		defer func() {
 			_ = d.conn.Close()
 		}()
 		err := waitForConnectionOpen(ctx, d.rtc)
 		if err != nil {
+			if errors.Is(err, context.DeadlineExceeded) {
+				_ = d.conn.Close()
+			}
 			errCh <- err
 			return
 		}
diff --git a/wsnet/dial_test.go b/wsnet/dial_test.go
@@ -9,6 +9,7 @@ import (
 	"net"
 	"strconv"
 	"testing"
+	"time"
 
 	"cdr.dev/slog/sloggers/slogtest"
 	"github.com/pion/ice/v2"
@@ -51,6 +52,18 @@ func ExampleDial_basic() {
 }
 
 func TestDial(t *testing.T) {
+	t.Run("Timeout", func(t *testing.T) {
+		t.Parallel()
+
+		connectAddr, _ := createDumbBroker(t)
+
+		ctx, cancelFunc := context.WithTimeout(context.Background(), time.Millisecond*50)
+		defer cancelFunc()
+		dialer, err := DialWebsocket(ctx, connectAddr, nil, nil)
+		require.True(t, errors.Is(err, context.DeadlineExceeded))
+		require.Error(t, dialer.conn.Close(), "already wrote close")
+	})
+
 	t.Run("Ping", func(t *testing.T) {
 		t.Parallel()
 
diff --git a/wsnet/rtc.go b/wsnet/rtc.go
@@ -256,7 +256,7 @@ func waitForConnectionOpen(ctx context.Context, conn *webrtc.PeerConnection) err
 	})
 	<-ctx.Done()
 	if ctx.Err() == context.DeadlineExceeded {
-		return ctx.Err()
+		return context.DeadlineExceeded
 	}
 	return nil
 }
diff --git a/wsnet/wsnet_test.go b/wsnet/wsnet_test.go
@@ -68,7 +68,9 @@ func createDumbBroker(t testing.TB) (connectAddr string, listenAddr string) {
 		mut.Lock()
 		defer mut.Unlock()
 		if sess == nil {
-			t.Error("listen not called")
+			// We discard inbound to emulate a pubsub where we don't know if anyone
+			// is listening on the other side.
+			_, _ = io.Copy(io.Discard, nc)
 			return
 		}
 		oc, err := sess.Open()

Original file line number	Diff line number	Diff line change
`@@ -256,7 +256,7 @@ func waitForConnectionOpen(ctx context.Context, conn *webrtc.PeerConnection) err`
`256`	`256`	`})`
`257`	`257`	`<-ctx.Done()`
`258`	`258`	`if ctx.Err() == context.DeadlineExceeded {`
`259`		`- return ctx.Err()`
	`259`	`+ return context.DeadlineExceeded`
`260`	`260`	`}`
`261`	`261`	`return nil`
`262`	`262`	`}`