Move `NormalizeIP` to netutil

Signed-off-by: Andrew Mason <amason@slack-corp.com>

go/netutil/netutil.go

@@ -189,3 +189,17 @@ func ResolveIPv4Addrs(addr string) ([]string, error) {
 	}
 	return result, nil
 }
+
+// NormalizeIP normalizes loopback addresses to avoid spurious errors when
+// communicating to different representations of the loopback.
+//
+// Note: this also maps IPv6 localhost to IPv4 localhost, as
+// TabletManagerClient.GetReplicas() (the only place this function is used on)
+// will return only IPv4 addresses.
+func NormalizeIP(s string) string {
+	if ip := net.ParseIP(s); ip != nil && ip.IsLoopback() {
+		return "127.0.0.1"
+	}
+
+	return s
+}

go/netutil/netutil_test.go

@@ -171,3 +171,20 @@ func TestResolveIPv4Addrs(t *testing.T) {
 		})
 	}
 }
+
+func TestNormalizeIP(t *testing.T) {
+	table := map[string]string{
+		"1.2.3.4":   "1.2.3.4",
+		"127.0.0.1": "127.0.0.1",
+		"127.0.1.1": "127.0.0.1",
+		// IPv6 must be mapped to IPv4.
+		"::1": "127.0.0.1",
+		// An unparseable IP should be returned as is.
+		"127.": "127.",
+	}
+	for input, want := range table {
+		if got := NormalizeIP(input); got != want {
+			t.Errorf("NormalizeIP(%#v) = %#v, want %#v", input, got, want)
+		}
+	}
+}

go/vt/wrangler/validator.go

@@ -19,11 +19,11 @@ package wrangler
 import (
 	"errors"
 	"fmt"
-	"net"
 	"sync"
 
 	"context"
 
+	"vitess.io/vitess/go/netutil"
 	"vitess.io/vitess/go/vt/topo"
 	"vitess.io/vitess/go/vt/topo/topoproto"
 
@@ -176,16 +176,6 @@ func (wr *Wrangler) validateShard(ctx context.Context, keyspace, shard string, p
 	}
 }
 
-func normalizeIP(ip string) string {
-	// Normalize loopback to avoid spurious validation errors.
-	if parsedIP := net.ParseIP(ip); parsedIP != nil && parsedIP.IsLoopback() {
-		// Note that this also maps IPv6 localhost to IPv4 localhost
-		// as GetReplicas() will return only IPv4 addresses.
-		return "127.0.0.1"
-	}
-	return ip
-}
-
 func (wr *Wrangler) validateReplication(ctx context.Context, shardInfo *topo.ShardInfo, tabletMap map[string]*topo.TabletInfo, results chan<- error) {
 	if shardInfo.PrimaryAlias == nil {
 		results <- fmt.Errorf("no primary in shard record %v/%v", shardInfo.Keyspace(), shardInfo.ShardName())
@@ -217,15 +207,15 @@ func (wr *Wrangler) validateReplication(ctx context.Context, shardInfo *topo.Sha
 			results <- fmt.Errorf("could not resolve IP for tablet %s: %v", tablet.Tablet.MysqlHostname, err)
 			continue
 		}
-		tabletIPMap[normalizeIP(ip)] = tablet.Tablet
+		tabletIPMap[netutil.NormalizeIP(ip)] = tablet.Tablet
 	}
 
 	// See if every replica is in the replication graph.
 	for _, replicaAddr := range replicaList {
-		if tabletIPMap[normalizeIP(replicaAddr)] == nil {
+		if tabletIPMap[netutil.NormalizeIP(replicaAddr)] == nil {
 			results <- fmt.Errorf("replica %v not in replication graph for shard %v/%v (mysql instance without vttablet?)", replicaAddr, shardInfo.Keyspace(), shardInfo.ShardName())
 		}
-		replicaIPMap[normalizeIP(replicaAddr)] = true
+		replicaIPMap[netutil.NormalizeIP(replicaAddr)] = true
 	}
 
 	// See if every entry in the replication graph is connected to the primary.
@@ -239,7 +229,7 @@ func (wr *Wrangler) validateReplication(ctx context.Context, shardInfo *topo.Sha
 			results <- fmt.Errorf("could not resolve IP for tablet %s: %v", tablet.Tablet.MysqlHostname, err)
 			continue
 		}
-		if !replicaIPMap[normalizeIP(ip)] {
+		if !replicaIPMap[netutil.NormalizeIP(ip)] {
 			results <- fmt.Errorf("replica %v not replicating: %v replica list: %q", topoproto.TabletAliasString(tablet.Alias), ip, replicaList)
 		}
 	}

go/vt/wrangler/validator_test.go

@@ -1,38 +0,0 @@
-/*
-Copyright 2019 The Vitess 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 wrangler
-
-import (
-	"testing"
-)
-
-func TestNormalizeIP(t *testing.T) {
-	table := map[string]string{
-		"1.2.3.4":   "1.2.3.4",
-		"127.0.0.1": "127.0.0.1",
-		"127.0.1.1": "127.0.0.1",
-		// IPv6 must be mapped to IPv4.
-		"::1": "127.0.0.1",
-		// An unparseable IP should be returned as is.
-		"127.": "127.",
-	}
-	for input, want := range table {
-		if got := normalizeIP(input); got != want {
-			t.Errorf("normalizeIP(%#v) = %#v, want %#v", input, got, want)
-		}
-	}
-}