From b586ae2f2597531837efdd99c4d309d4c6b7a17c Mon Sep 17 00:00:00 2001
From: Ludovic Fernandez <ldez@users.noreply.github.com>
Date: Tue, 15 Oct 2019 16:36:05 +0200
Subject: [PATCH] Remove deadcode.

---
 pkg/hostresolver/hostresolver.go      | 123 --------------------------
 pkg/hostresolver/hostresolver_test.go |  61 -------------
 2 files changed, 184 deletions(-)
 delete mode 100644 pkg/hostresolver/hostresolver.go
 delete mode 100644 pkg/hostresolver/hostresolver_test.go

diff --git a/pkg/hostresolver/hostresolver.go b/pkg/hostresolver/hostresolver.go
deleted file mode 100644
index 2a7c7dcee..000000000
--- a/pkg/hostresolver/hostresolver.go
+++ /dev/null
@@ -1,123 +0,0 @@
-package hostresolver
-
-import (
-	"fmt"
-	"net"
-	"sort"
-	"strings"
-	"time"
-
-	"github.com/containous/traefik/v2/pkg/log"
-	"github.com/miekg/dns"
-	"github.com/patrickmn/go-cache"
-)
-
-type cnameResolv struct {
-	TTL    time.Duration
-	Record string
-}
-
-type byTTL []*cnameResolv
-
-func (a byTTL) Len() int           { return len(a) }
-func (a byTTL) Swap(i, j int)      { a[i], a[j] = a[j], a[i] }
-func (a byTTL) Less(i, j int) bool { return a[i].TTL > a[j].TTL }
-
-// Resolver used for host resolver
-type Resolver struct {
-	CnameFlattening bool
-	ResolvConfig    string
-	ResolvDepth     int
-	cache           *cache.Cache
-}
-
-// CNAMEFlatten check if CNAME record exists, flatten if possible
-func (hr *Resolver) CNAMEFlatten(host string) (string, string) {
-	if hr.cache == nil {
-		hr.cache = cache.New(30*time.Minute, 5*time.Minute)
-	}
-
-	result := []string{host}
-	request := host
-
-	value, found := hr.cache.Get(host)
-	if found {
-		result = strings.Split(value.(string), ",")
-	} else {
-		var cacheDuration = 0 * time.Second
-
-		for depth := 0; depth < hr.ResolvDepth; depth++ {
-			resolv, err := cnameResolve(request, hr.ResolvConfig)
-			if err != nil {
-				log.Error(err)
-				break
-			}
-			if resolv == nil {
-				break
-			}
-
-			result = append(result, resolv.Record)
-			if depth == 0 {
-				cacheDuration = resolv.TTL
-			}
-			request = resolv.Record
-		}
-
-		if err := hr.cache.Add(host, strings.Join(result, ","), cacheDuration); err != nil {
-			log.Error(err)
-		}
-	}
-
-	return result[0], result[len(result)-1]
-}
-
-// cnameResolve resolves CNAME if exists, and return with the highest TTL
-func cnameResolve(host string, resolvPath string) (*cnameResolv, error) {
-	config, err := dns.ClientConfigFromFile(resolvPath)
-	if err != nil {
-		return nil, fmt.Errorf("invalid resolver configuration file: %s", resolvPath)
-	}
-
-	client := &dns.Client{Timeout: 30 * time.Second}
-
-	m := &dns.Msg{}
-	m.SetQuestion(dns.Fqdn(host), dns.TypeCNAME)
-
-	var result []*cnameResolv
-	for _, server := range config.Servers {
-		tempRecord, err := getRecord(client, m, server, config.Port)
-		if err != nil {
-			log.Errorf("Failed to resolve host %s: %v", host, err)
-			continue
-		}
-		result = append(result, tempRecord)
-	}
-
-	if len(result) == 0 {
-		return nil, nil
-	}
-
-	sort.Sort(byTTL(result))
-	return result[0], nil
-}
-
-func getRecord(client *dns.Client, msg *dns.Msg, server string, port string) (*cnameResolv, error) {
-	resp, _, err := client.Exchange(msg, net.JoinHostPort(server, port))
-	if err != nil {
-		return nil, fmt.Errorf("exchange error for server %s: %v", server, err)
-	}
-
-	if resp == nil || len(resp.Answer) == 0 {
-		return nil, fmt.Errorf("empty answer for server %s", server)
-	}
-
-	rr, ok := resp.Answer[0].(*dns.CNAME)
-	if !ok {
-		return nil, fmt.Errorf("invalid response type for server %s", server)
-	}
-
-	return &cnameResolv{
-		TTL:    time.Duration(rr.Hdr.Ttl) * time.Second,
-		Record: strings.TrimSuffix(rr.Target, "."),
-	}, nil
-}
diff --git a/pkg/hostresolver/hostresolver_test.go b/pkg/hostresolver/hostresolver_test.go
deleted file mode 100644
index ee6029f7d..000000000
--- a/pkg/hostresolver/hostresolver_test.go
+++ /dev/null
@@ -1,61 +0,0 @@
-package hostresolver
-
-import (
-	"testing"
-
-	"github.com/stretchr/testify/assert"
-)
-
-func TestCNAMEFlatten(t *testing.T) {
-	testCase := []struct {
-		desc           string
-		resolvFile     string
-		domain         string
-		expectedDomain string
-		isCNAME        bool
-	}{
-		{
-			desc:           "host request is CNAME record",
-			resolvFile:     "/etc/resolv.conf",
-			domain:         "www.github.com",
-			expectedDomain: "github.com",
-			isCNAME:        true,
-		},
-		{
-			desc:           "resolve file not found",
-			resolvFile:     "/etc/resolv.oops",
-			domain:         "www.github.com",
-			expectedDomain: "www.github.com",
-			isCNAME:        false,
-		},
-		{
-			desc:           "host request is not CNAME record",
-			resolvFile:     "/etc/resolv.conf",
-			domain:         "github.com",
-			expectedDomain: "github.com",
-			isCNAME:        false,
-		},
-	}
-
-	for _, test := range testCase {
-		test := test
-		t.Run(test.desc, func(t *testing.T) {
-			t.Parallel()
-
-			hostResolver := &Resolver{
-				ResolvConfig: test.resolvFile,
-				ResolvDepth:  5,
-			}
-
-			reqH, flatH := hostResolver.CNAMEFlatten(test.domain)
-			assert.Equal(t, test.domain, reqH)
-			assert.Equal(t, test.expectedDomain, flatH)
-
-			if test.isCNAME {
-				assert.NotEqual(t, test.expectedDomain, reqH)
-			} else {
-				assert.Equal(t, test.expectedDomain, reqH)
-			}
-		})
-	}
-}