add raw key ttl feature (#222)

Signed-off-by: iosmanthus <myosmanthustree@gmail.com>

integration_tests/tikv.toml

@@ -2,6 +2,7 @@
 addr = "127.0.0.1:20160"
 [storage]
 reserve-space = "1MB"
+enable-ttl = true
 [pd]
 endpoints = ["127.0.0.1:2379"]
 [rocksdb]

integration_tests/ttl_test.go

@@ -0,0 +1,94 @@
+// Copyright 2021 TiKV 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,
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package tikv_test
+
+import (
+	"context"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/require"
+	"github.com/stretchr/testify/suite"
+	"github.com/tikv/client-go/v2/config"
+	"github.com/tikv/client-go/v2/rawkv"
+)
+
+func TestTTL(t *testing.T) {
+	if !*withTiKV {
+		t.Skip("skipping TestTTL because with-tikv is not enabled")
+	}
+	suite.Run(t, new(ttlTestSuite))
+}
+
+type ttlTestSuite struct {
+	suite.Suite
+	client *rawkv.Client
+}
+
+func (s *ttlTestSuite) SetupTest() {
+	addrs := strings.Split(*pdAddrs, ",")
+	client, err := rawkv.NewClient(context.TODO(), addrs, config.DefaultConfig().Security)
+	require.Nil(s.T(), err)
+	s.client = client
+}
+
+func (s *ttlTestSuite) mustPutWithTTL(key, value []byte, ttl uint64) {
+	err := s.client.PutWithTTL(context.TODO(), key, value, ttl)
+	s.Nil(err)
+}
+
+func (s *ttlTestSuite) mustNotExist(key []byte) {
+	v, err := s.client.Get(context.TODO(), key)
+	s.Nil(err)
+	s.Nil(v)
+}
+
+func (s *ttlTestSuite) mustGetKeyTTL(key []byte) *uint64 {
+	ttl, err := s.client.GetKeyTTL(context.TODO(), key)
+	s.Nil(err)
+	return ttl
+}
+
+// TODO: we may mock this feature in unistore.
+func (s *ttlTestSuite) TestPutWithTTL() {
+	key := []byte("test-put-with-ttl")
+	value := []byte("value")
+	var ttl uint64 = 1
+	s.mustPutWithTTL(key, value, ttl)
+	time.Sleep(time.Second * time.Duration(ttl*2))
+	s.mustNotExist(key)
+}
+
+func (s *ttlTestSuite) TestGetKeyTTL() {
+	key := []byte("test-get-key-ttl")
+	value := []byte("value")
+	var ttl uint64 = 2
+	s.mustPutWithTTL(key, value, ttl)
+	time.Sleep(time.Second * time.Duration(ttl/2))
+
+	rest := s.mustGetKeyTTL(key)
+	s.NotNil(rest)
+	s.LessOrEqual(*rest, ttl/2)
+
+	time.Sleep(time.Second * time.Duration(ttl/2))
+	s.mustNotExist(key)
+
+	rest = s.mustGetKeyTTL(key)
+	s.Nil(rest)
+}
+
+func (s *ttlTestSuite) TearDownTest() {
+	s.client.Close()
+}

rawkv/rawkv.go

@@ -172,8 +172,8 @@ func (c *Client) BatchGet(ctx context.Context, keys [][]byte) ([][]byte, error)
 	return values, nil
 }
 
-// Put stores a key-value pair to TiKV.
-func (c *Client) Put(ctx context.Context, key, value []byte) error {
+// PutWithTTL stores a key-value pair to TiKV with a time-to-live duration.
+func (c *Client) PutWithTTL(ctx context.Context, key, value []byte, ttl uint64) error {
 	start := time.Now()
 	defer func() { metrics.RawkvCmdHistogramWithBatchPut.Observe(time.Since(start).Seconds()) }()
 	metrics.RawkvSizeHistogramWithKey.Observe(float64(len(key)))
@@ -186,6 +186,7 @@ func (c *Client) Put(ctx context.Context, key, value []byte) error {
 	req := tikvrpc.NewRequest(tikvrpc.CmdRawPut, &kvrpcpb.RawPutRequest{
 		Key:    key,
 		Value:  value,
+		Ttl:    ttl,
 		ForCas: c.atomic,
 	})
 	resp, _, err := c.sendReq(ctx, key, req, false)
@@ -202,6 +203,40 @@ func (c *Client) Put(ctx context.Context, key, value []byte) error {
 	return nil
 }
 
+// GetKeyTTL get the TTL of a raw key from TiKV if key exists
+func (c *Client) GetKeyTTL(ctx context.Context, key []byte) (*uint64, error) {
+	var ttl uint64
+	metrics.RawkvSizeHistogramWithKey.Observe(float64(len(key)))
+	req := tikvrpc.NewRequest(tikvrpc.CmdGetKeyTTL, &kvrpcpb.RawGetKeyTTLRequest{
+		Key: key,
+	})
+	resp, _, err := c.sendReq(ctx, key, req, false)
+
+	if err != nil {
+		return nil, errors.Trace(err)
+	}
+	if resp.Resp == nil {
+		return nil, errors.Trace(tikverr.ErrBodyMissing)
+	}
+
+	cmdResp := resp.Resp.(*kvrpcpb.RawGetKeyTTLResponse)
+	if cmdResp.GetError() != "" {
+		return nil, errors.New(cmdResp.GetError())
+	}
+
+	if cmdResp.GetNotFound() {
+		return nil, nil
+	}
+
+	ttl = cmdResp.GetTtl()
+	return &ttl, nil
+}
+
+// Put stores a key-value pair to TiKV.
+func (c *Client) Put(ctx context.Context, key, value []byte) error {
+	return c.PutWithTTL(ctx, key, value, 0)
+}
+
 // BatchPut stores key-value pairs to TiKV.
 func (c *Client) BatchPut(ctx context.Context, keys, values [][]byte) error {
 	start := time.Now()

tikvrpc/tikvrpc.go

@@ -79,6 +79,7 @@ const (
 	CmdRawBatchDelete
 	CmdRawDeleteRange
 	CmdRawScan
+	CmdGetKeyTTL
 	CmdRawCompareAndSwap
 
 	CmdUnsafeDestroyRange
@@ -362,6 +363,11 @@ func (req *Request) UnsafeDestroyRange() *kvrpcpb.UnsafeDestroyRangeRequest {
 	return req.Req.(*kvrpcpb.UnsafeDestroyRangeRequest)
 }
 
+// RawGetKeyTTL returns RawGetKeyTTLRequest in request.
+func (req *Request) RawGetKeyTTL() *kvrpcpb.RawGetKeyTTLRequest {
+	return req.Req.(*kvrpcpb.RawGetKeyTTLRequest)
+}
+
 // RawCompareAndSwap returns RawCASRequest in request.
 func (req *Request) RawCompareAndSwap() *kvrpcpb.RawCASRequest {
 	return req.Req.(*kvrpcpb.RawCASRequest)
@@ -683,6 +689,8 @@ func SetContext(req *Request, region *metapb.Region, peer *metapb.Peer) error {
 		req.RawScan().Context = ctx
 	case CmdUnsafeDestroyRange:
 		req.UnsafeDestroyRange().Context = ctx
+	case CmdGetKeyTTL:
+		req.RawGetKeyTTL().Context = ctx
 	case CmdRawCompareAndSwap:
 		req.RawCompareAndSwap().Context = ctx
 	case CmdRegisterLockObserver:
@@ -815,6 +823,10 @@ func GenRegionErrorResp(req *Request, e *errorpb.Error) (*Response, error) {
 		p = &kvrpcpb.UnsafeDestroyRangeResponse{
 			RegionError: e,
 		}
+	case CmdGetKeyTTL:
+		p = &kvrpcpb.RawGetKeyTTLResponse{
+			RegionError: e,
+		}
 	case CmdRawCompareAndSwap:
 		p = &kvrpcpb.RawCASResponse{
 			RegionError: e,
@@ -931,6 +943,8 @@ func CallRPC(ctx context.Context, client tikvpb.TikvClient, req *Request) (*Resp
 		resp.Resp, err = client.RawScan(ctx, req.RawScan())
 	case CmdUnsafeDestroyRange:
 		resp.Resp, err = client.UnsafeDestroyRange(ctx, req.UnsafeDestroyRange())
+	case CmdGetKeyTTL:
+		resp.Resp, err = client.RawGetKeyTTL(ctx, req.RawGetKeyTTL())
 	case CmdRawCompareAndSwap:
 		resp.Resp, err = client.RawCompareAndSwap(ctx, req.RawCompareAndSwap())
 	case CmdRegisterLockObserver: