Add a dummy implementation of proxyutil.LineBuffer

Rather than actually assembling all of the rules we aren't going to
use, just count them and throw them away.

pkg/proxy/iptables/proxier.go

@@ -288,10 +288,10 @@ func NewProxier(ipFamily v1.IPFamily,
 		precomputedProbabilities: make([]string, 0, 1001),
 		iptablesData:             bytes.NewBuffer(nil),
 		existingFilterChainsData: bytes.NewBuffer(nil),
-		filterChains:             proxyutil.LineBuffer{},
+		filterChains:             proxyutil.NewLineBuffer(),
-		filterRules:              proxyutil.LineBuffer{},
+		filterRules:              proxyutil.NewLineBuffer(),
-		natChains:                proxyutil.LineBuffer{},
+		natChains:                proxyutil.NewLineBuffer(),
-		natRules:                 proxyutil.LineBuffer{},
+		natRules:                 proxyutil.NewLineBuffer(),
 		localhostNodePorts:       localhostNodePorts,
 		nodePortAddresses:        nodePortAddresses,
 		networkInterfacer:        proxyutil.RealNetwork{},
@@ -411,8 +411,8 @@ func CleanupLeftovers(ipt utiliptables.Interface) (encounteredError bool) {
 		encounteredError = true
 	} else {
 		existingNATChains := utiliptables.GetChainsFromTable(iptablesData.Bytes())
-		natChains := &proxyutil.LineBuffer{}
+		natChains := proxyutil.NewLineBuffer()
-		natRules := &proxyutil.LineBuffer{}
+		natRules := proxyutil.NewLineBuffer()
 		natChains.Write("*nat")
 		// Start with chains we know we need to remove.
 		for _, chain := range []utiliptables.Chain{kubeServicesChain, kubeNodePortsChain, kubePostroutingChain} {
@@ -448,8 +448,8 @@ func CleanupLeftovers(ipt utiliptables.Interface) (encounteredError bool) {
 		encounteredError = true
 	} else {
 		existingFilterChains := utiliptables.GetChainsFromTable(iptablesData.Bytes())
-		filterChains := &proxyutil.LineBuffer{}
+		filterChains := proxyutil.NewLineBuffer()
-		filterRules := &proxyutil.LineBuffer{}
+		filterRules := proxyutil.NewLineBuffer()
 		filterChains.Write("*filter")
 		for _, chain := range []utiliptables.Chain{kubeServicesChain, kubeExternalServicesChain, kubeForwardChain, kubeNodePortsChain} {
 			if _, found := existingFilterChains[chain]; found {
@@ -852,8 +852,8 @@ func (proxier *Proxier) syncProxyRules() {
 	proxier.natChains.Reset()
 	proxier.natRules.Reset()
 
-	skippedNatChains := &proxyutil.LineBuffer{}
+	skippedNatChains := proxyutil.NewDiscardLineBuffer()
-	skippedNatRules := &proxyutil.LineBuffer{}
+	skippedNatRules := proxyutil.NewDiscardLineBuffer()
 
 	// Write chain lines for all the "top-level" chains we'll be filling in
 	for _, chainName := range []utiliptables.Chain{kubeServicesChain, kubeExternalServicesChain, kubeForwardChain, kubeNodePortsChain, kubeProxyFirewallChain} {
@@ -1069,9 +1069,9 @@ func (proxier *Proxier) syncProxyRules() {
 			}
 		}
 
-		filterRules := &proxier.filterRules
+		filterRules := proxier.filterRules
-		natChains := &proxier.natChains
+		natChains := proxier.natChains
-		natRules := &proxier.natRules
+		natRules := proxier.natRules
 
 		// Capture the clusterIP.
 		if hasInternalEndpoints {
@@ -1562,7 +1562,7 @@ func (proxier *Proxier) syncProxyRules() {
 	conntrack.CleanStaleEntries(proxier.iptables.IsIPv6(), proxier.exec, proxier.svcPortMap, serviceUpdateResult, endpointUpdateResult)
 }
 
-func (proxier *Proxier) writeServiceToEndpointRules(natRules *proxyutil.LineBuffer, svcPortNameString string, svcInfo proxy.ServicePort, svcChain utiliptables.Chain, endpoints []proxy.Endpoint, args []string) {
+func (proxier *Proxier) writeServiceToEndpointRules(natRules proxyutil.LineBuffer, svcPortNameString string, svcInfo proxy.ServicePort, svcChain utiliptables.Chain, endpoints []proxy.Endpoint, args []string) {
 	// First write session affinity rules, if applicable.
 	if svcInfo.SessionAffinityType() == v1.ServiceAffinityClientIP {
 		for _, ep := range endpoints {

pkg/proxy/iptables/proxier_test.go

@@ -324,10 +324,10 @@ func NewFakeProxier(ipt utiliptables.Interface) *Proxier {
 		precomputedProbabilities: make([]string, 0, 1001),
 		iptablesData:             bytes.NewBuffer(nil),
 		existingFilterChainsData: bytes.NewBuffer(nil),
-		filterChains:             proxyutil.LineBuffer{},
+		filterChains:             proxyutil.NewLineBuffer(),
-		filterRules:              proxyutil.LineBuffer{},
+		filterRules:              proxyutil.NewLineBuffer(),
-		natChains:                proxyutil.LineBuffer{},
+		natChains:                proxyutil.NewLineBuffer(),
-		natRules:                 proxyutil.LineBuffer{},
+		natRules:                 proxyutil.NewLineBuffer(),
 		nodeIP:                   netutils.ParseIPSloppy(testNodeIP),
 		localhostNodePorts:       true,
 		nodePortAddresses:        proxyutil.NewNodePortAddresses(ipfamily, nil),

pkg/proxy/ipvs/proxier.go

@@ -440,10 +440,10 @@ func NewProxier(ipFamily v1.IPFamily,
 		ipvsScheduler:         scheduler,
 		iptablesData:          bytes.NewBuffer(nil),
 		filterChainsData:      bytes.NewBuffer(nil),
-		natChains:             proxyutil.LineBuffer{},
+		natChains:             proxyutil.NewLineBuffer(),
-		natRules:              proxyutil.LineBuffer{},
+		natRules:              proxyutil.NewLineBuffer(),
-		filterChains:          proxyutil.LineBuffer{},
+		filterChains:          proxyutil.NewLineBuffer(),
-		filterRules:           proxyutil.LineBuffer{},
+		filterRules:           proxyutil.NewLineBuffer(),
 		netlinkHandle:         NewNetLinkHandle(ipFamily == v1.IPv6Protocol),
 		ipset:                 ipset,
 		nodePortAddresses:     nodePortAddresses,

pkg/proxy/ipvs/proxier_test.go

@@ -163,10 +163,10 @@ func NewFakeProxier(ipt utiliptables.Interface, ipvs utilipvs.Interface, ipset u
 		ipvsScheduler:         defaultScheduler,
 		iptablesData:          bytes.NewBuffer(nil),
 		filterChainsData:      bytes.NewBuffer(nil),
-		natChains:             proxyutil.LineBuffer{},
+		natChains:             proxyutil.NewLineBuffer(),
-		natRules:              proxyutil.LineBuffer{},
+		natRules:              proxyutil.NewLineBuffer(),
-		filterChains:          proxyutil.LineBuffer{},
+		filterChains:          proxyutil.NewLineBuffer(),
-		filterRules:           proxyutil.LineBuffer{},
+		filterRules:           proxyutil.NewLineBuffer(),
 		netlinkHandle:         netlinkHandle,
 		ipsetList:             ipsetList,
 		nodePortAddresses:     proxyutil.NewNodePortAddresses(ipFamily, nil),

pkg/proxy/util/linebuffer.go

@@ -0,0 +1,150 @@
+/*
+Copyright 2023 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package util
+
+import (
+	"bytes"
+	"fmt"
+)
+
+// LineBuffer is an interface for writing lines of input to a bytes.Buffer
+type LineBuffer interface {
+	// Write takes a list of arguments, each a string or []string, joins all the
+	// individual strings with spaces, terminates with newline, and writes them to the
+	// buffer. Any other argument type will panic.
+	Write(args ...interface{})
+
+	// WriteBytes writes bytes to the buffer, and terminates with newline.
+	WriteBytes(bytes []byte)
+
+	// Reset clears the buffer
+	Reset()
+
+	// Bytes returns the contents of the buffer as a []byte
+	Bytes() []byte
+
+	// String returns the contents of the buffer as a string
+	String() string
+
+	// Lines returns the number of lines in the buffer. Note that more precisely, this
+	// returns the number of times Write() or WriteBytes() was called; it assumes that
+	// you never wrote any newlines to the buffer yourself.
+	Lines() int
+}
+
+type realLineBuffer struct {
+	b     bytes.Buffer
+	lines int
+}
+
+// NewLineBuffer returns a new "real" LineBuffer
+func NewLineBuffer() LineBuffer {
+	return &realLineBuffer{}
+}
+
+// Write is part of LineBuffer
+func (buf *realLineBuffer) Write(args ...interface{}) {
+	for i, arg := range args {
+		if i > 0 {
+			buf.b.WriteByte(' ')
+		}
+		switch x := arg.(type) {
+		case string:
+			buf.b.WriteString(x)
+		case []string:
+			for j, s := range x {
+				if j > 0 {
+					buf.b.WriteByte(' ')
+				}
+				buf.b.WriteString(s)
+			}
+		default:
+			panic(fmt.Sprintf("unknown argument type: %T", x))
+		}
+	}
+	buf.b.WriteByte('\n')
+	buf.lines++
+}
+
+// WriteBytes is part of LineBuffer
+func (buf *realLineBuffer) WriteBytes(bytes []byte) {
+	buf.b.Write(bytes)
+	buf.b.WriteByte('\n')
+	buf.lines++
+}
+
+// Reset is part of LineBuffer
+func (buf *realLineBuffer) Reset() {
+	buf.b.Reset()
+	buf.lines = 0
+}
+
+// Bytes is part of LineBuffer
+func (buf *realLineBuffer) Bytes() []byte {
+	return buf.b.Bytes()
+}
+
+// String is part of LineBuffer
+func (buf *realLineBuffer) String() string {
+	return buf.b.String()
+}
+
+// Lines is part of LineBuffer
+func (buf *realLineBuffer) Lines() int {
+	return buf.lines
+}
+
+type discardLineBuffer struct {
+	lines int
+}
+
+// NewDiscardLineBuffer returns a dummy LineBuffer that counts the number of writes but
+// throws away the data. (This is used for iptables proxy partial syncs, to keep track of
+// how many rules we managed to avoid having to sync.)
+func NewDiscardLineBuffer() LineBuffer {
+	return &discardLineBuffer{}
+}
+
+// Write is part of LineBuffer
+func (buf *discardLineBuffer) Write(args ...interface{}) {
+	buf.lines++
+}
+
+// WriteBytes is part of LineBuffer
+func (buf *discardLineBuffer) WriteBytes(bytes []byte) {
+	buf.lines++
+}
+
+// Reset is part of LineBuffer
+func (buf *discardLineBuffer) Reset() {
+	buf.lines = 0
+}
+
+// Bytes is part of LineBuffer
+func (buf *discardLineBuffer) Bytes() []byte {
+	return []byte{}
+}
+
+// String is part of LineBuffer
+func (buf *discardLineBuffer) String() string {
+	return ""
+}
+
+// Lines is part of LineBuffer
+func (buf *discardLineBuffer) Lines() int {
+	return buf.lines
+}

pkg/proxy/util/linebuffer_test.go

@@ -0,0 +1,168 @@
+/*
+Copyright 2023 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package util
+
+import (
+	"math/rand"
+	"strings"
+	"testing"
+)
+
+func TestLineBufferWrite(t *testing.T) {
+	testCases := []struct {
+		name     string
+		input    []interface{}
+		expected string
+	}{
+		{
+			name:     "none",
+			input:    []interface{}{},
+			expected: "\n",
+		},
+		{
+			name:     "one string",
+			input:    []interface{}{"test1"},
+			expected: "test1\n",
+		},
+		{
+			name:     "one slice",
+			input:    []interface{}{[]string{"test1", "test2"}},
+			expected: "test1 test2\n",
+		},
+		{
+			name:     "mixed",
+			input:    []interface{}{"s1", "s2", []string{"s3", "s4"}, "", "s5", []string{}, []string{"s6"}, "s7"},
+			expected: "s1 s2 s3 s4  s5  s6 s7\n",
+		},
+	}
+	testBuffer := NewLineBuffer()
+	for _, testCase := range testCases {
+		t.Run(testCase.name, func(t *testing.T) {
+			testBuffer.Reset()
+			testBuffer.Write(testCase.input...)
+			if want, got := testCase.expected, testBuffer.String(); !strings.EqualFold(want, got) {
+				t.Fatalf("write word is %v\n expected: %q, got: %q", testCase.input, want, got)
+			}
+			if testBuffer.Lines() != 1 {
+				t.Fatalf("expected 1 line, got: %d", testBuffer.Lines())
+			}
+		})
+	}
+}
+
+func TestLineBufferWritePanic(t *testing.T) {
+	defer func() {
+		if r := recover(); r == nil {
+			t.Errorf("did not panic")
+		}
+	}()
+	testBuffer := NewLineBuffer()
+	testBuffer.Write("string", []string{"a", "slice"}, 1234)
+}
+
+func TestLineBufferWriteBytes(t *testing.T) {
+	testCases := []struct {
+		name     string
+		bytes    []byte
+		expected string
+	}{
+		{
+			name:     "empty bytes",
+			bytes:    []byte{},
+			expected: "\n",
+		},
+		{
+			name:     "test bytes",
+			bytes:    []byte("test write bytes line"),
+			expected: "test write bytes line\n",
+		},
+	}
+
+	testBuffer := NewLineBuffer()
+	for _, testCase := range testCases {
+		t.Run(testCase.name, func(t *testing.T) {
+			testBuffer.Reset()
+			testBuffer.WriteBytes(testCase.bytes)
+			if want, got := testCase.expected, testBuffer.String(); !strings.EqualFold(want, got) {
+				t.Fatalf("write bytes is %v\n expected: %s, got: %s", testCase.bytes, want, got)
+			}
+		})
+	}
+}
+
+// obtained from https://stackoverflow.com/a/22892986
+var letters = []rune("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ")
+
+func randSeq() string {
+	b := make([]rune, 30)
+	for i := range b {
+		b[i] = letters[rand.Intn(len(letters))]
+	}
+	return string(b)
+}
+
+func TestWriteCountLines(t *testing.T) {
+	testCases := []struct {
+		name     string
+		expected int
+	}{
+		{
+			name:     "write no line",
+			expected: 0,
+		},
+		{
+			name:     "write one line",
+			expected: 1,
+		},
+		{
+			name:     "write 100 lines",
+			expected: 100,
+		},
+		{
+			name:     "write 1000 lines",
+			expected: 1000,
+		},
+		{
+			name:     "write 10000 lines",
+			expected: 10000,
+		},
+		{
+			name:     "write 100000 lines",
+			expected: 100000,
+		},
+	}
+	testBuffer := NewLineBuffer()
+	discardBuffer := NewDiscardLineBuffer()
+	for _, testCase := range testCases {
+		t.Run(testCase.name, func(t *testing.T) {
+			testBuffer.Reset()
+			discardBuffer.Reset()
+			for i := 0; i < testCase.expected; i++ {
+				testBuffer.Write(randSeq())
+				discardBuffer.Write(randSeq())
+			}
+			n := testBuffer.Lines()
+			if n != testCase.expected {
+				t.Fatalf("lines expected: %d, got: %d", testCase.expected, n)
+			}
+			n = discardBuffer.Lines()
+			if n != testCase.expected {
+				t.Fatalf("discardBuffer lines expected: %d, got: %d", testCase.expected, n)
+			}
+		})
+	}
+}

pkg/proxy/util/utils.go

@@ -17,7 +17,6 @@ limitations under the License.
 package util
 
 import (
-	"bytes"
 	"context"
 	"fmt"
 	"net"
@@ -321,67 +320,6 @@ func GetClusterIPByFamily(ipFamily v1.IPFamily, service *v1.Service) string {
 	return ""
 }
 
-type LineBuffer struct {
-	b     bytes.Buffer
-	lines int
-}
-
-// Write takes a list of arguments, each a string or []string, joins all the
-// individual strings with spaces, terminates with newline, and writes to buf.
-// Any other argument type will panic.
-func (buf *LineBuffer) Write(args ...interface{}) {
-	for i, arg := range args {
-		if i > 0 {
-			buf.b.WriteByte(' ')
-		}
-		switch x := arg.(type) {
-		case string:
-			buf.b.WriteString(x)
-		case []string:
-			for j, s := range x {
-				if j > 0 {
-					buf.b.WriteByte(' ')
-				}
-				buf.b.WriteString(s)
-			}
-		default:
-			panic(fmt.Sprintf("unknown argument type: %T", x))
-		}
-	}
-	buf.b.WriteByte('\n')
-	buf.lines++
-}
-
-// WriteBytes writes bytes to buffer, and terminates with newline.
-func (buf *LineBuffer) WriteBytes(bytes []byte) {
-	buf.b.Write(bytes)
-	buf.b.WriteByte('\n')
-	buf.lines++
-}
-
-// Reset clears buf
-func (buf *LineBuffer) Reset() {
-	buf.b.Reset()
-	buf.lines = 0
-}
-
-// Bytes returns the contents of buf as a []byte
-func (buf *LineBuffer) Bytes() []byte {
-	return buf.b.Bytes()
-}
-
-// String returns the contents of buf as a string
-func (buf *LineBuffer) String() string {
-	return buf.b.String()
-}
-
-// Lines returns the number of lines in buf. Note that more precisely, this returns the
-// number of times Write() or WriteBytes() was called; it assumes that you never wrote
-// any newlines to the buffer yourself.
-func (buf *LineBuffer) Lines() int {
-	return buf.lines
-}
-
 // RevertPorts is closing ports in replacementPortsMap but not in originalPortsMap. In other words, it only
 // closes the ports opened in this sync.
 func RevertPorts(replacementPortsMap, originalPortsMap map[netutils.LocalPort]netutils.Closeable) {

pkg/proxy/util/utils_test.go

@@ -17,10 +17,8 @@ limitations under the License.
 package util
 
 import (
-	"math/rand"
 	"net"
 	"reflect"
-	"strings"
 	"testing"
 
 	v1 "k8s.io/api/core/v1"
@@ -707,145 +705,6 @@ func TestRevertPorts(t *testing.T) {
 	}
 }
 
-func TestLineBufferWrite(t *testing.T) {
-	testCases := []struct {
-		name     string
-		input    []interface{}
-		expected string
-	}{
-		{
-			name:     "none",
-			input:    []interface{}{},
-			expected: "\n",
-		},
-		{
-			name:     "one string",
-			input:    []interface{}{"test1"},
-			expected: "test1\n",
-		},
-		{
-			name:     "one slice",
-			input:    []interface{}{[]string{"test1", "test2"}},
-			expected: "test1 test2\n",
-		},
-		{
-			name:     "mixed",
-			input:    []interface{}{"s1", "s2", []string{"s3", "s4"}, "", "s5", []string{}, []string{"s6"}, "s7"},
-			expected: "s1 s2 s3 s4  s5  s6 s7\n",
-		},
-	}
-	testBuffer := LineBuffer{}
-	for _, testCase := range testCases {
-		t.Run(testCase.name, func(t *testing.T) {
-			testBuffer.Reset()
-			testBuffer.Write(testCase.input...)
-			if want, got := testCase.expected, testBuffer.String(); !strings.EqualFold(want, got) {
-				t.Fatalf("write word is %v\n expected: %q, got: %q", testCase.input, want, got)
-			}
-			if testBuffer.Lines() != 1 {
-				t.Fatalf("expected 1 line, got: %d", testBuffer.Lines())
-			}
-		})
-	}
-}
-
-func TestLineBufferWritePanic(t *testing.T) {
-	defer func() {
-		if r := recover(); r == nil {
-			t.Errorf("did not panic")
-		}
-	}()
-	testBuffer := LineBuffer{}
-	testBuffer.Write("string", []string{"a", "slice"}, 1234)
-}
-
-func TestLineBufferWriteBytes(t *testing.T) {
-	testCases := []struct {
-		name     string
-		bytes    []byte
-		expected string
-	}{
-		{
-			name:     "empty bytes",
-			bytes:    []byte{},
-			expected: "\n",
-		},
-		{
-			name:     "test bytes",
-			bytes:    []byte("test write bytes line"),
-			expected: "test write bytes line\n",
-		},
-	}
-
-	testBuffer := LineBuffer{}
-	for _, testCase := range testCases {
-		t.Run(testCase.name, func(t *testing.T) {
-			testBuffer.Reset()
-			testBuffer.WriteBytes(testCase.bytes)
-			if want, got := testCase.expected, testBuffer.String(); !strings.EqualFold(want, got) {
-				t.Fatalf("write bytes is %v\n expected: %s, got: %s", testCase.bytes, want, got)
-			}
-		})
-	}
-}
-
-func TestWriteCountLines(t *testing.T) {
-
-	testCases := []struct {
-		name     string
-		expected int
-	}{
-		{
-			name:     "write no line",
-			expected: 0,
-		},
-		{
-			name:     "write one line",
-			expected: 1,
-		},
-		{
-			name:     "write 100 lines",
-			expected: 100,
-		},
-		{
-			name:     "write 1000 lines",
-			expected: 1000,
-		},
-		{
-			name:     "write 10000 lines",
-			expected: 10000,
-		},
-		{
-			name:     "write 100000 lines",
-			expected: 100000,
-		},
-	}
-	testBuffer := LineBuffer{}
-	for _, testCase := range testCases {
-		t.Run(testCase.name, func(t *testing.T) {
-			testBuffer.Reset()
-			for i := 0; i < testCase.expected; i++ {
-				testBuffer.Write(randSeq())
-			}
-			n := testBuffer.Lines()
-			if n != testCase.expected {
-				t.Fatalf("lines expected: %d, got: %d", testCase.expected, n)
-			}
-		})
-	}
-}
-
-// obtained from https://stackoverflow.com/a/22892986
-var letters = []rune("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ")
-
-func randSeq() string {
-	b := make([]rune, 30)
-	for i := range b {
-		b[i] = letters[rand.Intn(len(letters))]
-	}
-	return string(b)
-}
-
 func mustParseIPAddr(str string) net.Addr {
 	a, err := net.ResolveIPAddr("ip", str)
 	if err != nil {