From 2cba13896e2f46dee127071d0777a6bff65e21b6 Mon Sep 17 00:00:00 2001
From: Dustin Deus <deusdustin@gmail.com>
Date: Mon, 18 Nov 2024 17:41:02 +0100
Subject: [PATCH] fix: do netPoll detection once and set it globally (#1384)

---
 router/core/router.go    | 21 +++++++++++++++++++++
 router/core/websocket.go | 29 +++++++----------------------
 2 files changed, 28 insertions(+), 22 deletions(-)

diff --git a/router/core/router.go b/router/core/router.go
index a2ef32029..fec7458a0 100644
--- a/router/core/router.go
+++ b/router/core/router.go
@@ -6,6 +6,7 @@ import (
 	"crypto/x509"
 	"errors"
 	"fmt"
+	"github.com/wundergraph/graphql-go-tools/v2/pkg/netpoll"
 	"net"
 	"net/http"
 	"net/url"
@@ -515,6 +516,26 @@ func NewRouter(opts ...Option) (*Router, error) {
 		r.logger.Info("Kafka Event source enabled", zap.String("provider_id", source.ID), zap.Strings("brokers", source.Brokers))
 	}
 
+	if !r.engineExecutionConfiguration.EnableNetPoll {
+		r.logger.Warn("Net poller is disabled by configuration. Falling back to less efficient connection handling method.")
+	} else if err := netpoll.Supported(); err != nil {
+
+		// Disable netPoll if it's not supported. This flag is used everywhere to decide whether to use netPoll or not.
+		r.engineExecutionConfiguration.EnableNetPoll = false
+
+		if errors.Is(err, netpoll.ErrUnsupported) {
+			r.logger.Warn(
+				"Net poller is only available on Linux and MacOS. Falling back to less efficient connection handling method.",
+				zap.Error(err),
+			)
+		} else {
+			r.logger.Warn(
+				"Net poller is not functional by the environment. Ensure that the system supports epoll/kqueue and that necessary syscall permissions are granted. Falling back to less efficient connection handling method.",
+				zap.Error(err),
+			)
+		}
+	}
+
 	return r, nil
 }
 
diff --git a/router/core/websocket.go b/router/core/websocket.go
index 5384605b8..53eae6540 100644
--- a/router/core/websocket.go
+++ b/router/core/websocket.go
@@ -122,30 +122,15 @@ func NewWebsocketMiddleware(ctx context.Context, opts WebsocketMiddlewareOptions
 		handler.forwardQueryParamsConfig.withRegexAllowList = len(handler.forwardQueryParamsConfig.regexAllowList) > 0
 	}
 	if opts.EnableNetPoll {
-		if err := netpoll.Supported(); err != nil {
-			if errors.Is(err, netpoll.ErrUnsupported) {
-				opts.Logger.Warn(
-					"Net poller is only available on Linux and MacOS. Falling back to less efficient connection handling method.",
-					zap.Error(err),
-				)
-			} else {
-				opts.Logger.Warn(
-					"Net poller is not functional by the environment. Ensure that the system supports epoll/kqueue and that necessary syscall permissions are granted. Falling back to less efficient connection handling method.",
-					zap.Error(err),
-				)
-			}
-		} else {
-			poller, err := netpoll.NewPoller(opts.NetPollConnBufferSize, opts.NetPollTimeout)
-			if err == nil {
-				opts.Logger.Debug("Net poller is available")
+		poller, err := netpoll.NewPoller(opts.NetPollConnBufferSize, opts.NetPollTimeout)
+		if err == nil {
+			opts.Logger.Debug("Net poller is available")
 
-				handler.netPoll = poller
-				handler.connections = make(map[int]*WebSocketConnectionHandler)
-				go handler.runPoller()
-			}
+			handler.netPoll = poller
+			handler.connections = make(map[int]*WebSocketConnectionHandler)
+			go handler.runPoller()
 		}
-	} else {
-		opts.Logger.Warn("Net poller is disabled by configuration. Falling back to less efficient connection handling method.")
+
 	}
 
 	return func(next http.Handler) http.Handler {