rate limit: make context aware (#731)

* rate limits: Make context aware

* binance: rate limit allow for cancellation of reservation when deadline is exceeded

* request: add context.done() before initiating any bulk work.

* binance: update error return for rate limiting

* request: updated dealine check to remove after time.Now procedure as this will obfuscate a deadline which will be limited by the context check on every attempt, so no need to sleep with delay.

exchanges/request/request_test.go

@@ -180,20 +180,18 @@ type GlobalLimitTest struct {
 
 var errEndpointLimitNotFound = errors.New("endpoint limit not found")
 
-func (g *GlobalLimitTest) Limit(e EndpointLimit) error {
+func (g *GlobalLimitTest) Limit(ctx context.Context, e EndpointLimit) error {
 	switch e {
 	case Auth:
 		if g.Auth == nil {
 			return errors.New("auth rate not set")
 		}
-		time.Sleep(g.Auth.Reserve().Delay())
-		return nil
+		return g.Auth.Wait(ctx)
 	case UnAuth:
 		if g.UnAuth == nil {
 			return errors.New("unauth rate not set")
 		}
-		time.Sleep(g.UnAuth.Reserve().Delay())
-		return nil
+		return g.UnAuth.Wait(ctx)
 	default:
 		return fmt.Errorf("cannot execute functionality: %d %w",
 			e,
@@ -527,11 +525,24 @@ func TestBasicLimiter(t *testing.T) {
 	ctx := context.Background()
 
 	tn := time.Now()
-	_ = r.SendPayload(ctx, Unset, func() (*Item, error) { return &i, nil })
-	_ = r.SendPayload(ctx, Unset, func() (*Item, error) { return &i, nil })
+	err := r.SendPayload(ctx, Unset, func() (*Item, error) { return &i, nil })
+	if err != nil {
+		t.Fatal(err)
+	}
+	err = r.SendPayload(ctx, Unset, func() (*Item, error) { return &i, nil })
+	if err != nil {
+		t.Fatal(err)
+	}
 	if time.Since(tn) < time.Second {
 		t.Error("rate limit issues")
 	}
+
+	ctx, cancel := context.WithDeadline(ctx, tn.Add(time.Nanosecond))
+	defer cancel()
+	err = r.SendPayload(ctx, Unset, func() (*Item, error) { return &i, nil })
+	if !errors.Is(err, context.DeadlineExceeded) {
+		t.Fatalf("receieved: %v but expected: %v", err, context.DeadlineExceeded)
+	}
 }
 
 func TestEnableDisableRateLimit(t *testing.T) {