Added function to derive shard name for SrvShard.

go/vt/topo/srvshard.go

@@ -6,6 +6,7 @@ package topo
 
 import (
 	"bytes"
+	"fmt"
 	"sort"
 
 	"github.com/youtube/vitess/go/bson"
@@ -13,6 +14,10 @@ import (
 	"github.com/youtube/vitess/go/vt/key"
 )
 
+// This is the shard name for when the keyrange covers the entire space
+// for unsharded database.
+const SHARD_ZERO = "0"
+
 // SrvShard contains a roll-up of the shard in the local namespace.
 // In zk, it is under /zk/local/vt/ns/<keyspace>/<shard>
 type SrvShard struct {
@@ -120,6 +125,13 @@ func (ss *SrvShard) UnmarshalBson(buf *bytes.Buffer) {
 	}
 }
 
+func (ss *SrvShard) ShardName() string {
+	if !ss.KeyRange.IsPartial() {
+		return SHARD_ZERO
+	}
+	return fmt.Sprintf("%v-%v", ss.KeyRange.Start, ss.KeyRange.End)
+}
+
 // KeyspacePartition represents a continuous set of shards to
 // serve an entire data set.
 type KeyspacePartition struct {