etcdserver: support sorted range requests in v3 api

Fixes #4166

etcdctlv3/command/range_command.go

@@ -16,6 +16,7 @@ package command
 
 import (
 	"fmt"
+	"strings"
 
 	"github.com/coreos/etcd/Godeps/_workspace/src/github.com/spf13/cobra"
 	"github.com/coreos/etcd/Godeps/_workspace/src/golang.org/x/net/context"
@@ -23,13 +24,23 @@ import (
 	pb "github.com/coreos/etcd/etcdserver/etcdserverpb"
 )
 
+var (
+	rangeLimit      int
+	rangeSortOrder  string
+	rangeSortTarget string
+)
+
 // NewRangeCommand returns the cobra command for "range".
 func NewRangeCommand() *cobra.Command {
-	return &cobra.Command{
+	cmd := &cobra.Command{
 		Use:   "range",
 		Short: "Range gets the keys in the range from the store.",
 		Run:   rangeCommandFunc,
 	}
+	cmd.Flags().StringVar(&rangeSortOrder, "order", "", "order of results; ASCEND or DESCEND")
+	cmd.Flags().StringVar(&rangeSortTarget, "sort-by", "", "sort target; CREATE, KEY, MODIFY, VALUE, or VERSION")
+	cmd.Flags().IntVar(&rangeLimit, "limit", 0, "maximum number of results")
+	return cmd
 }
 
 // rangeCommandFunc executes the "range" command.
@@ -48,13 +59,51 @@ func rangeCommandFunc(cmd *cobra.Command, args []string) {
 	if err != nil {
 		ExitWithError(ExitError, err)
 	}
+
+	sortByOrder := pb.RangeRequest_NONE
+	sortOrder := strings.ToUpper(rangeSortOrder)
+	switch {
+	case sortOrder == "ASCEND":
+		sortByOrder = pb.RangeRequest_ASCEND
+	case sortOrder == "DESCEND":
+		sortByOrder = pb.RangeRequest_DESCEND
+	case sortOrder == "":
+		sortByOrder = pb.RangeRequest_NONE
+	default:
+		ExitWithError(ExitBadFeature, fmt.Errorf("bad sort order %v", rangeSortOrder))
+	}
+
+	sortByTarget := pb.RangeRequest_KEY
+	sortTarget := strings.ToUpper(rangeSortTarget)
+	switch {
+	case sortTarget == "CREATE":
+		sortByTarget = pb.RangeRequest_CREATE
+	case sortTarget == "KEY":
+		sortByTarget = pb.RangeRequest_KEY
+	case sortTarget == "MODIFY":
+		sortByTarget = pb.RangeRequest_MOD
+	case sortTarget == "VALUE":
+		sortByTarget = pb.RangeRequest_VALUE
+	case sortTarget == "VERSION":
+		sortByTarget = pb.RangeRequest_VERSION
+	case sortTarget == "":
+		sortByTarget = pb.RangeRequest_KEY
+	default:
+		ExitWithError(ExitBadFeature, fmt.Errorf("bad sort target %v", rangeSortTarget))
+	}
+
 	conn, err := grpc.Dial(endpoint)
 	if err != nil {
 		ExitWithError(ExitBadConnection, err)
 	}
 	kv := pb.NewKVClient(conn)
-	req := &pb.RangeRequest{Key: key, RangeEnd: rangeEnd}
-
+	req := &pb.RangeRequest{
+		Key:        key,
+		RangeEnd:   rangeEnd,
+		SortOrder:  sortByOrder,
+		SortTarget: sortByTarget,
+		Limit:      int64(rangeLimit),
+	}
 	resp, err := kv.Range(context.Background(), req)
 	for _, kv := range resp.Kvs {
 		fmt.Printf("%s %s\n", string(kv.Key), string(kv.Value))