exhttp: Add IsNetworkError helper

Author: hifi

exhttp/networkerror.go

@@ -0,0 +1,43 @@
+// Copyright (c) 2025 Tulir Asokan
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+package exhttp
+
+import (
+	"errors"
+	"net"
+	"syscall"
+
+	"golang.org/x/net/http2"
+)
+
+func IsNetworkError(err error) bool {
+	for err != nil {
+		if _, ok := err.(net.Error); ok {
+			return true
+		} else if _, ok := err.(*net.OpError); ok {
+			return true
+		} else if errno, ok := err.(syscall.Errno); ok {
+			// common errnos for network related operations
+			return errno == syscall.ENETDOWN ||
+				errno == syscall.ENETUNREACH ||
+				errno == syscall.ENETRESET ||
+				errno == syscall.ECONNABORTED ||
+				errno == syscall.ECONNRESET ||
+				errno == syscall.ENOBUFS ||
+				errno == syscall.ETIMEDOUT ||
+				errno == syscall.ECONNREFUSED ||
+				errno == syscall.EHOSTDOWN ||
+				errno == syscall.EHOSTUNREACH
+		} else if errors.As(err, &http2.StreamError{}); ok {
+			return true
+		}
+
+		err = errors.Unwrap(err)
+	}
+
+	return false
+}

go.mod

@@ -11,6 +11,7 @@ require (
 	github.com/rs/zerolog v1.34.0
 	github.com/stretchr/testify v1.10.0
 	golang.org/x/exp v0.0.0-20250506013437-ce4c2cf36ca6
+	golang.org/x/net v0.40.0
 	golang.org/x/sys v0.33.0
 	golang.org/x/text v0.25.0
 	google.golang.org/protobuf v1.36.6

go.sum

@@ -27,6 +27,8 @@ github.com/stretchr/testify v1.10.0 h1:Xv5erBjTwe/5IxqUQTdXv5kgmIvbHo3QQyRwhJsOf
 github.com/stretchr/testify v1.10.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
 golang.org/x/exp v0.0.0-20250506013437-ce4c2cf36ca6 h1:y5zboxd6LQAqYIhHnB48p0ByQ/GnQx2BE33L8BOHQkI=
 golang.org/x/exp v0.0.0-20250506013437-ce4c2cf36ca6/go.mod h1:U6Lno4MTRCDY+Ba7aCcauB9T60gsv5s4ralQzP72ZoQ=
+golang.org/x/net v0.40.0 h1:79Xs7wF06Gbdcg4kdCCIQArK11Z1hr5POQ6+fIYHNuY=
+golang.org/x/net v0.40.0/go.mod h1:y0hY0exeL2Pku80/zKK7tpntoX23cqL3Oa6njdgRtds=
 golang.org/x/sys v0.0.0-20220811171246-fbc7d0a398ab/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.12.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=