fix: update websocket handlers to eliminate goroutine leaks (#796) (#797

)

Hi team,

Please see the suggested fixes to address the issue I raised:
#796

After this change, the websocket handlers and their goroutines are
closing as expected. As a result, my memory usage is much more lower and
no longer leaking.

![image](https://github.com/wundergraph/graphql-go-tools/assets/53241741/b2a6667f-6fc7-48f4-b20f-afd2fdca2220)

Thanks,
Benny

Co-authored-by: Aenimus <47415099+Aenimus@users.noreply.github.com>

pkg/engine/datasource/graphql_datasource/graphql_ws_handler.go

@@ -103,12 +103,18 @@ func (h *gqlWSConnectionHandler) readBlocking(ctx context.Context, dataCh chan [
 	for {
 		msgType, data, err := h.conn.Read(ctx)
 		if ctx.Err() != nil {
-			errCh <- ctx.Err()
-			return
+			select {
+			case errCh <- ctx.Err():
+			case <-ctx.Done():
+				return
+			}
 		}
 		if err != nil {
-			errCh <- err
-			return
+			select {
+			case errCh <- err:
+			case <-ctx.Done():
+				return
+			}
 		}
 		if msgType != websocket.MessageText {
 			continue

pkg/subscription/legacy_handler.go

@@ -388,6 +388,9 @@ func (h *Handler) handleKeepAlive(ctx context.Context) {
 		case <-ctx.Done():
 			return
 		case <-time.After(h.keepAliveInterval):
+			if !h.client.IsConnected() {
+				return
+			}
 			h.sendKeepAlive()
 		}
 	}