etcdctl/ctlv3: add 'lease list' command

Signed-off-by: Gyu-Ho Lee <gyuhox@gmail.com>

etcdctl/README.md

@@ -439,6 +439,26 @@ Prints lease information.
 # {"cluster_id":17186838941855831277,"member_id":4845372305070271874,"revision":3,"raft_term":2,"id":3279279168933706764,"ttl":459,"granted-ttl":500,"keys":["Zm9vMQ==","Zm9vMg=="]}
 ```
 
+### LEASE LIST
+
+LEASE LIST lists all active leases.
+
+RPC: LeaseLeases
+
+#### Output
+
+Prints a message with a list of active leases.
+
+#### Example
+
+```bash
+./etcdctl lease grant 10
+# lease 32695410dcc0ca06 granted with TTL(10s)
+
+./etcdctl lease list
+32695410dcc0ca06
+```
+
 ### LEASE KEEP-ALIVE \<leaseID\>
 
 LEASE KEEP-ALIVE periodically refreshes a lease so it does not expire.
@@ -736,9 +756,9 @@ If NOSPACE alarm is present:
 
 ### DEFRAG [options]
 
-DEFRAG defragments the backend database file for a set of given endpoints while etcd is running, or directly defragments an 
-etcd data directory while etcd is not running. When an etcd member reclaims storage space from deleted and compacted keys, the 
-space is kept in a free list and the database file remains the same size. By defragmenting the database, the etcd member 
+DEFRAG defragments the backend database file for a set of given endpoints while etcd is running, or directly defragments an
+etcd data directory while etcd is not running. When an etcd member reclaims storage space from deleted and compacted keys, the
+space is kept in a free list and the database file remains the same size. By defragmenting the database, the etcd member
 releases this free space back to the file system.
 
 #### Options

etcdctl/ctlv3/command/lease_command.go

@@ -33,6 +33,7 @@ func NewLeaseCommand() *cobra.Command {
 	lc.AddCommand(NewLeaseGrantCommand())
 	lc.AddCommand(NewLeaseRevokeCommand())
 	lc.AddCommand(NewLeaseTimeToLiveCommand())
+	lc.AddCommand(NewLeaseListCommand())
 	lc.AddCommand(NewLeaseKeepAliveCommand())
 
 	return lc
@@ -129,6 +130,25 @@ func leaseTimeToLiveCommandFunc(cmd *cobra.Command, args []string) {
 	display.TimeToLive(*resp, timeToLiveKeys)
 }
 
+// NewLeaseListCommand returns the cobra command for "lease list".
+func NewLeaseListCommand() *cobra.Command {
+	lc := &cobra.Command{
+		Use:   "list",
+		Short: "List all active leases",
+		Run:   leaseListCommandFunc,
+	}
+	return lc
+}
+
+// leaseListCommandFunc executes the "lease list" command.
+func leaseListCommandFunc(cmd *cobra.Command, args []string) {
+	resp, rerr := mustClientFromCmd(cmd).Leases(context.TODO())
+	if rerr != nil {
+		ExitWithError(ExitBadConnection, rerr)
+	}
+	display.Leases(*resp)
+}
+
 // NewLeaseKeepAliveCommand returns the cobra command for "lease keep-alive".
 func NewLeaseKeepAliveCommand() *cobra.Command {
 	lc := &cobra.Command{

etcdctl/ctlv3/command/printer.go

@@ -36,6 +36,7 @@ type printer interface {
 	Revoke(id v3.LeaseID, r v3.LeaseRevokeResponse)
 	KeepAlive(r v3.LeaseKeepAliveResponse)
 	TimeToLive(r v3.LeaseTimeToLiveResponse, keys bool)
+	Leases(r v3.LeaseLeasesResponse)
 
 	MemberAdd(v3.MemberAddResponse)
 	MemberRemove(id uint64, r v3.MemberRemoveResponse)
@@ -96,6 +97,7 @@ func (p *printerRPC) Grant(r v3.LeaseGrantResponse)                      { p.p(r
 func (p *printerRPC) Revoke(id v3.LeaseID, r v3.LeaseRevokeResponse)     { p.p(r) }
 func (p *printerRPC) KeepAlive(r v3.LeaseKeepAliveResponse)              { p.p(r) }
 func (p *printerRPC) TimeToLive(r v3.LeaseTimeToLiveResponse, keys bool) { p.p(&r) }
+func (p *printerRPC) Leases(r v3.LeaseLeasesResponse)                    { p.p(&r) }
 
 func (p *printerRPC) MemberAdd(r v3.MemberAddResponse) { p.p((*pb.MemberAddResponse)(&r)) }
 func (p *printerRPC) MemberRemove(id uint64, r v3.MemberRemoveResponse) {

etcdctl/ctlv3/command/printer_fields.go

@@ -118,6 +118,13 @@ func (p *fieldsPrinter) TimeToLive(r v3.LeaseTimeToLiveResponse, keys bool) {
 	}
 }
 
+func (p *fieldsPrinter) Leases(r v3.LeaseLeasesResponse) {
+	p.hdr(r.ResponseHeader)
+	for _, item := range r.Leases {
+		fmt.Println(`"ID" :`, item.ID)
+	}
+}
+
 func (p *fieldsPrinter) MemberList(r v3.MemberListResponse) {
 	p.hdr(r.Header)
 	for _, m := range r.Members {

etcdctl/ctlv3/command/printer_simple.go

@@ -104,6 +104,13 @@ func (s *simplePrinter) TimeToLive(resp v3.LeaseTimeToLiveResponse, keys bool) {
 	fmt.Println(txt)
 }
 
+func (s *simplePrinter) Leases(resp v3.LeaseLeasesResponse) {
+	fmt.Printf("found %d leases\n", len(resp.Leases))
+	for _, item := range resp.Leases {
+		fmt.Printf("%016x\n", item.ID)
+	}
+}
+
 func (s *simplePrinter) Alarm(resp v3.AlarmResponse) {
 	for _, e := range resp.Alarms {
 		fmt.Printf("%+v\n", e)