Correctly parse cell names with dashes in tablet aliases

go/vt/topo/topoproto/tablet.go

@@ -21,6 +21,7 @@ package topoproto
 import (
 	"fmt"
 	"net"
+	"regexp"
 	"sort"
 	"strconv"
 	"strings"
@@ -75,19 +76,23 @@ func TabletAliasUIDStr(ta *topodatapb.TabletAlias) string {
 	return fmt.Sprintf("%010d", ta.Uid)
 }
 
+const tabletAliasFormat = "^(?P<cell>[-_.a-zA-Z0-9]+)-(?P<uid>[0-9]+)$"
+
+var tabletAliasRegexp = regexp.MustCompile(tabletAliasFormat)
+
 // ParseTabletAlias returns a TabletAlias for the input string,
 // of the form <cell>-<uid>
 func ParseTabletAlias(aliasStr string) (*topodatapb.TabletAlias, error) {
-	nameParts := strings.Split(aliasStr, "-")
-	if len(nameParts) != 2 {
-		return nil, fmt.Errorf("invalid tablet alias: '%s', expecting format: '<cell>-<uid>'", aliasStr)
+	nameParts := tabletAliasRegexp.FindStringSubmatch(aliasStr)
+	if len(nameParts) != 3 {
+		return nil, fmt.Errorf("invalid tablet alias: '%s', expecting format: '%s'", aliasStr, tabletAliasFormat)
 	}
-	uid, err := ParseUID(nameParts[1])
+	uid, err := ParseUID(nameParts[tabletAliasRegexp.SubexpIndex("uid")])
 	if err != nil {
 		return nil, vterrors.Wrapf(err, "invalid tablet uid in alias '%s'", aliasStr)
 	}
 	return &topodatapb.TabletAlias{
-		Cell: nameParts[0],
+		Cell: nameParts[tabletAliasRegexp.SubexpIndex("cell")],
 		Uid:  uid,
 	}, nil
 }

go/vt/topo/topoproto/tablet_test.go

@@ -0,0 +1,72 @@
+/*
+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 topoproto
+
+import (
+	"fmt"
+	"testing"
+
+	topodatapb "vitess.io/vitess/go/vt/proto/topodata"
+)
+
+func TestParseTabletAlias(t *testing.T) {
+	for aliasStr, expectedAlias := range map[string]*topodatapb.TabletAlias{
+		// valid cases
+		"cell1-42":                         {Cell: "cell1", Uid: 42},
+		"cell1_1-42":                       {Cell: "cell1_1", Uid: 42},
+		"cell1_1-0":                        {Cell: "cell1_1", Uid: 0},
+		"cell1_1--1":                       {Cell: "cell1_1-", Uid: 1},
+		"1-022222":                         {Cell: "1", Uid: 22222},
+		"global-read-only-000000000000042": {Cell: "global-read-only", Uid: 42},
+		"-cell1-1---42":                    {Cell: "-cell1-1--", Uid: 42},
+		"cell1____-42":                     {Cell: "cell1____", Uid: 42},
+		"__cell1-1-1-2-42":                 {Cell: "__cell1-1-1-2", Uid: 42},
+
+		// invalid cases
+		"":          nil,
+		"42":        nil,
+		"-42":       nil,
+		"cell1":     nil,
+		"cell1-":    nil,
+		"cell1_42":  nil,
+		",cell1-42": nil,
+	} {
+		alias, err := ParseTabletAlias(aliasStr)
+
+		if expectedAlias == nil {
+			if err == nil {
+				t.Fatalf("Expected to fail parsing invalid tablet alias: %s but got no error", aliasStr)
+			} else {
+				expectedErr := fmt.Errorf("invalid tablet alias: '%s', expecting format: '%s'", aliasStr, tabletAliasFormat)
+				if err.Error() != expectedErr.Error() {
+					t.Fatalf("Expected error: %s but got: %s", expectedErr, err)
+				}
+				continue
+			}
+		}
+
+		if err != nil {
+			t.Fatalf("Failed to parse valid tablet alias: %s, err: %s", aliasStr, err)
+		}
+		if alias.Cell != expectedAlias.Cell {
+			t.Fatalf("Cell parsed from tabletAlias: %s is %s but expected %s", aliasStr, alias.Cell, expectedAlias.Cell)
+		}
+		if alias.Uid != expectedAlias.Uid {
+			t.Fatalf("Uid parsed from tabletAlias: %s is %d but expected %d", aliasStr, alias.Uid, expectedAlias.Uid)
+		}
+	}
+}