OPTIM: Enable dynamic update of HAProxy map files

Dynamic update of map files was dropped in 7953394 due to issues
inherent to HAProxy 2.3 (details provided in said commit).
In HAProxy 2.4+ those issues were fixed thus dynamic map update is
enabled again.

Updating the map file is done via the following steps:
1. Prepare the map file via `prepare map` command: this is going to
   create a new version of the map file.
2. Pushing content via `add map @<newVersion> <map> <payload>` command:
   where payload should not be bigger than haproxy tune.bufsize (default
   is 16384B), if map content is bigger than bufsize then this command
   should be called multiple times (content/payload times).
3. Loading the new version of the map file via `commit map`:

Author: Mo3m3n

go.mod

@@ -5,7 +5,7 @@ go 1.17
 require (
 	github.com/go-test/deep v1.0.7
 	github.com/google/renameio v1.0.1
-	github.com/haproxytech/client-native/v3 v3.1.1-0.20220510114028-57f50c20a1bf
+	github.com/haproxytech/client-native/v3 v3.1.1-0.20220520145135-9afaaf96bc7f
 	github.com/haproxytech/config-parser/v4 v4.0.0-rc2.0.20220428133329-7d0ec01198d4
 	github.com/jessevdk/go-flags v1.4.0
 	github.com/pires/go-proxyproto v0.6.1

go.sum

@@ -268,8 +268,8 @@ github.com/googleapis/gnostic v0.5.5 h1:9fHAtK0uDfpveeqqo1hkEZJcFvYXAiCN3UutL8F9
 github.com/googleapis/gnostic v0.5.5/go.mod h1:7+EbHbldMins07ALC74bsA81Ovc97DwqyJO1AENw9kA=
 github.com/gorilla/websocket v1.4.2/go.mod h1:YR8l580nyteQvAITg2hZ9XVh4b55+EU/adAjf1fMHhE=
 github.com/gregjones/httpcache v0.0.0-20180305231024-9cad4c3443a7/go.mod h1:FecbI9+v66THATjSRHfNgh1IVFe/9kFxbXtjV0ctIMA=
-github.com/haproxytech/client-native/v3 v3.1.1-0.20220510114028-57f50c20a1bf h1:MotDEEbRdSuRIi7M4y8MvUEhLWO5IelS2CGySl4iPpM=
-github.com/haproxytech/client-native/v3 v3.1.1-0.20220510114028-57f50c20a1bf/go.mod h1:W3WGOnzwpgXp483BCs8Xj40gejn4rNfhRgfQrJXL/sc=
+github.com/haproxytech/client-native/v3 v3.1.1-0.20220520145135-9afaaf96bc7f h1:jV+f9lmAOqSJF3IBgrEFq5qrLBt73zuMRimdy0iJVis=
+github.com/haproxytech/client-native/v3 v3.1.1-0.20220520145135-9afaaf96bc7f/go.mod h1:W3WGOnzwpgXp483BCs8Xj40gejn4rNfhRgfQrJXL/sc=
 github.com/haproxytech/config-parser/v4 v4.0.0-rc2.0.20220428133329-7d0ec01198d4 h1:aTSSDkGwoDwGv0hRfKsaWxVejDW8iROlPPBhboI3ONk=
 github.com/haproxytech/config-parser/v4 v4.0.0-rc2.0.20220428133329-7d0ec01198d4/go.mod h1:pEuHx+aFhn0lIdvAg1OaawQfeRkpq1I8HzjtZN4/PLI=
 github.com/haproxytech/go-logger v1.0.1-0.20211022075555-178f1cdf4d84 h1:rSLHjJ4VGvMZcGAGQ9GaXuhvdswu1iLVXTThLX6OKN8=

pkg/haproxy/api/api.go

@@ -60,7 +60,7 @@ type HAProxyClient interface {
 	GlobalCfgSnippet(snippet []string) error
 	GetMap(mapFile string) (*models.Map, error)
 	RefreshBackends() (deleted []string, err error)
-	SetMapContent(mapFile string, payload string) error
+	SetMapContent(mapFile string, payload []string) error
 	SetServerAddr(backendName string, serverName string, ip string, port int) error
 	SetServerState(backendName string, serverName string, state string) error
 	ServerGet(serverName, backendNa string) (models.Server, error)

pkg/haproxy/api/runtime.go

@@ -1,12 +1,17 @@
 package api
 
 import (
+	"fmt"
+	"strings"
+
 	"github.com/haproxytech/client-native/v3/models"
 
 	"github.com/haproxytech/kubernetes-ingress/pkg/store"
 	"github.com/haproxytech/kubernetes-ingress/pkg/utils"
 )
 
+var ErrMapNotFound = fmt.Errorf("map not found")
+
 func (c *clientNative) ExecuteRaw(command string) (result []string, err error) {
 	runtime, err := c.nativeAPI.Runtime()
 	if err != nil {
@@ -31,16 +36,37 @@ func (c *clientNative) SetServerState(backendName string, serverName string, sta
 	return runtime.SetServerState(backendName, serverName, state)
 }
 
-func (c *clientNative) SetMapContent(mapFile string, payload string) error {
+func (c *clientNative) SetMapContent(mapFile string, payload []string) error {
+	var mapVer, mapPath string
 	runtime, err := c.nativeAPI.Runtime()
 	if err != nil {
 		return err
 	}
-	err = runtime.ClearMap(mapFile, false)
+	mapVer, err = runtime.PrepareMap(mapFile)
+	if err != nil {
+		if strings.HasPrefix(err.Error(), "maps dir doesn't exists") {
+			err = ErrMapNotFound
+		}
+		err = fmt.Errorf("error preparing map file: %w", err)
+		return err
+	}
+	mapPath, err = runtime.GetMapsPath(mapFile)
 	if err != nil {
+		err = fmt.Errorf("error getting map path: %w", err)
 		return err
 	}
-	return runtime.AddMapPayload(mapFile, payload)
+	for i := 0; i < len(payload); i++ {
+		_, err = runtime.ExecuteRaw(fmt.Sprintf("add map @%s %s <<\n%s\n", mapVer, mapPath, payload[i]))
+		if err != nil {
+			err = fmt.Errorf("error loading map payload: %w", err)
+			return err
+		}
+	}
+	err = runtime.CommitMap(mapVer, mapFile)
+	if err != nil {
+		err = fmt.Errorf("error committing map file: %w", err)
+	}
+	return err
 }
 
 func (c *clientNative) GetMap(mapFile string) (*models.Map, error) {

pkg/haproxy/maps/main.go

@@ -15,6 +15,7 @@
 package maps
 
 import (
+	"errors"
 	"fmt"
 	"hash/fnv"
 	"os"
@@ -48,6 +49,10 @@ var logger = utils.GetLogger()
 
 var mapDir string
 
+// bufsize is the default value of HAproxy tune.bufsize.
+// Map payload cannot be bigger than tune.bufsize
+const bufSize = 16000
+
 type mapFile struct {
 	rows       []string
 	hash       uint64
@@ -56,17 +61,25 @@ type mapFile struct {
 	// because it is always referenced in a haproxy rule.
 }
 
-func (mf *mapFile) getContent() (string, uint64) {
-	var b strings.Builder
+// getContent returns the content of a haproxy map file in a list of chunks
+// where each chunk is <= bufsie. It also returns a hash of the map content
+func (mf *mapFile) getContent() (result []string, hash uint64) {
+	var chunk strings.Builder
 	sort.Strings(mf.rows)
+	h := fnv.New64a()
 	for _, r := range mf.rows {
-		b.WriteString(r)
-		b.WriteRune('\n')
+		if chunk.Len()+len(r) >= bufSize {
+			result = append(result, chunk.String())
+			chunk.Reset()
+		}
+		chunk.WriteString(r)
+		chunk.WriteRune('\n')
+		_, _ = h.Write([]byte(r))
 	}
-	content := b.String()
-	h := fnv.New64a()
-	_, _ = h.Write([]byte(content))
-	return content, h.Sum64()
+	if chunk.Len() > 0 {
+		result = append(result, chunk.String())
+	}
+	return result, h.Sum64()
 }
 
 func New(dir string, persistentMaps []Name) (Maps, error) {
@@ -111,7 +124,7 @@ func (m mapFiles) RefreshMaps(client api.HAProxyClient) (reload bool) {
 		var f *os.File
 		var err error
 		filename := GetPath(name)
-		if content == "" && !mapFile.persistent {
+		if len(content) == 0 && !mapFile.persistent {
 			logger.Error(os.Remove(string(filename)))
 			delete(m, name)
 			continue
@@ -120,21 +133,21 @@ func (m mapFiles) RefreshMaps(client api.HAProxyClient) (reload bool) {
 			continue
 		}
 		defer f.Close()
-		if _, err = f.WriteString(content); err != nil {
-			logger.Error(err)
-			continue
+		for _, d := range content {
+			if _, err = f.WriteString(d); err != nil {
+				logger.Error(err)
+				return
+			}
 		}
 		logger.Error(f.Sync())
-		reload = true
-		logger.Debugf("Map file '%s' updated, reload required", name)
-		// if err = client.SetMapContent(name, content); err != nil {
-		// 	if strings.HasPrefix(err.Error(), "maps dir doesn't exists") {
-		// 		logger.Debugf("creating Map file %s", name)
-		// 	} else {
-		// 		logger.Warningf("dynamic update of '%s' Map file failed: %s", name, err.Error()[:200])
-		// 	}
-		// 	reload = true
-		// }
+		if err = client.SetMapContent(string(name), content); err != nil {
+			if errors.Is(err, api.ErrMapNotFound) {
+				logger.Debugf("Map file %s created, reload required", name)
+			} else {
+				logger.Debugf("Runtime update of map file '%s' failed, reload required: %s", name, err)
+			}
+			reload = true
+		}
 	}
 	return reload
 }