fixes a bug that connection refused error cannot be recognized correctly

Author: likakuli

staging/src/k8s.io/apimachinery/pkg/util/net/util.go

@@ -54,3 +54,20 @@ func IsConnectionReset(err error) bool {
 	}
 	return false
 }
+
+// Returns if the given err is "connection refused" error
+func IsConnectionRefused(err error) bool {
+	if urlErr, ok := err.(*url.Error); ok {
+		err = urlErr.Err
+	}
+	if opErr, ok := err.(*net.OpError); ok {
+		err = opErr.Err
+	}
+	if osErr, ok := err.(*os.SyscallError); ok {
+		err = osErr.Err
+	}
+	if errno, ok := err.(syscall.Errno); ok && errno == syscall.ECONNREFUSED {
+		return true
+	}
+	return false
+}

staging/src/k8s.io/apimachinery/pkg/util/net/util_test.go

@@ -18,6 +18,9 @@ package net
 
 import (
 	"net"
+	"net/url"
+	"os"
+	"syscall"
 	"testing"
 )
 
@@ -66,3 +69,28 @@ func TestIPNetEqual(t *testing.T) {
 		}
 	}
 }
+
+func TestIsConnectionRefused(t *testing.T) {
+	testCases := []struct {
+		err    error
+		expect bool
+	}{
+		{
+			&url.Error{Err: &net.OpError{Err: syscall.ECONNRESET}},
+			false,
+		},
+		{
+			&url.Error{Err: &net.OpError{Err: syscall.ECONNREFUSED}},
+			true,
+		},
+		{&url.Error{Err: &net.OpError{Err: &os.SyscallError{Err: syscall.ECONNREFUSED}}},
+			true,
+		},
+	}
+
+	for _, tc := range testCases {
+		if result := IsConnectionRefused(tc.err); result != tc.expect {
+			t.Errorf("Expect to be %v, but actual is %v", tc.expect, result)
+		}
+	}
+}

staging/src/k8s.io/client-go/tools/cache/BUILD

@@ -76,6 +76,7 @@ go_library(
         "//staging/src/k8s.io/apimachinery/pkg/util/clock:go_default_library",
         "//staging/src/k8s.io/apimachinery/pkg/util/diff:go_default_library",
         "//staging/src/k8s.io/apimachinery/pkg/util/naming:go_default_library",
+        "//staging/src/k8s.io/apimachinery/pkg/util/net:go_default_library",
         "//staging/src/k8s.io/apimachinery/pkg/util/runtime:go_default_library",
         "//staging/src/k8s.io/apimachinery/pkg/util/sets:go_default_library",
         "//staging/src/k8s.io/apimachinery/pkg/util/wait:go_default_library",

staging/src/k8s.io/client-go/tools/cache/reflector.go

@@ -22,11 +22,8 @@ import (
 	"fmt"
 	"io"
 	"math/rand"
-	"net"
-	"net/url"
 	"reflect"
 	"sync"
-	"syscall"
 	"time"
 
 	apierrs "k8s.io/apimachinery/pkg/api/errors"
@@ -35,6 +32,7 @@ import (
 	"k8s.io/apimachinery/pkg/runtime"
 	"k8s.io/apimachinery/pkg/util/clock"
 	"k8s.io/apimachinery/pkg/util/naming"
+	utilnet "k8s.io/apimachinery/pkg/util/net"
 	utilruntime "k8s.io/apimachinery/pkg/util/runtime"
 	"k8s.io/apimachinery/pkg/util/wait"
 	"k8s.io/apimachinery/pkg/watch"
@@ -285,13 +283,9 @@ func (r *Reflector) ListAndWatch(stopCh <-chan struct{}) error {
 			// It doesn't make sense to re-list all objects because most likely we will be able to restart
 			// watch where we ended.
 			// If that's the case wait and resend watch request.
-			if urlError, ok := err.(*url.Error); ok {
-				if opError, ok := urlError.Err.(*net.OpError); ok {
-					if errno, ok := opError.Err.(syscall.Errno); ok && errno == syscall.ECONNREFUSED {
-						time.Sleep(time.Second)
-						continue
-					}
-				}
+			if utilnet.IsConnectionRefused(err) {
+				time.Sleep(time.Second)
+				continue
 			}
 			return nil
 		}

staging/src/k8s.io/client-go/tools/cache/reflector_test.go

@@ -24,7 +24,7 @@ import (
 	"testing"
 	"time"
 
-	v1 "k8s.io/api/core/v1"
+	"k8s.io/api/core/v1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/runtime"
 	"k8s.io/apimachinery/pkg/util/wait"