tso: optimize the err handling and make their specification consistent

pkg/errs/errno.go

@@ -18,6 +18,8 @@ import "github.com/pingcap/errors"
 // The internal error which is generated in PD project.
 // tso errors
 var (
+	ErrResetUserTimestamp  = errors.Normalize("reset user timestamp failed, %s", errors.RFCCodeText("PD:tso:ErrResetUserTimestamp"))
+	ErrGenerateTimestamp   = errors.Normalize("generate timestamp failed, %s", errors.RFCCodeText("PD:tso:ErrGenerateTimestamp"))
 	ErrInvalidTimestamp    = errors.Normalize("invalid timestamp", errors.RFCCodeText("PD:tso:ErrInvalidTimestamp"))
 	ErrLogicOverflow       = errors.Normalize("logic part overflow", errors.RFCCodeText("PD:tso:ErrLogicOverflow"))
 	ErrIncorrectSystemTime = errors.Normalize("incorrect system time", errors.RFCCodeText("PD:tso:ErrIncorrectSystemTime"))

server/tso/global_allocator.go

@@ -17,7 +17,6 @@ import (
 	"sync/atomic"
 	"time"
 
-	"github.com/pingcap/errors"
 	"github.com/pingcap/failpoint"
 	"github.com/pingcap/kvproto/pkg/pdpb"
 	"github.com/pingcap/log"
@@ -87,7 +86,7 @@ func (gta *GlobalTSOAllocator) GenerateTSO(count uint32) (pdpb.Timestamp, error)
 	var resp pdpb.Timestamp
 
 	if count == 0 {
-		return resp, errors.New("tso count should be positive")
+		return resp, errs.ErrGenerateTimestamp.FastGenByArgs("tso count should be positive")
 	}
 
 	maxRetryCount := 10
@@ -105,7 +104,7 @@ func (gta *GlobalTSOAllocator) GenerateTSO(count uint32) (pdpb.Timestamp, error)
 				continue
 			}
 			log.Error("invalid timestamp", zap.Any("timestamp", current), errs.ZapError(errs.ErrInvalidTimestamp))
-			return pdpb.Timestamp{}, errors.New("can not get timestamp, may be not leader")
+			return pdpb.Timestamp{}, errs.ErrGenerateTimestamp.FastGenByArgs("timestamp in memory isn't initialized")
 		}
 
 		resp.Physical = current.physical.UnixNano() / int64(time.Millisecond)
@@ -120,11 +119,11 @@ func (gta *GlobalTSOAllocator) GenerateTSO(count uint32) (pdpb.Timestamp, error)
 		}
 		// In case lease expired after the first check.
 		if !gta.leadership.Check() {
-			return pdpb.Timestamp{}, errors.New("alloc timestamp failed, lease expired")
+			return pdpb.Timestamp{}, errs.ErrGenerateTimestamp.FastGenByArgs("not the pd leader")
 		}
 		return resp, nil
 	}
-	return resp, errors.New("can not get timestamp")
+	return resp, errs.ErrGenerateTimestamp.FastGenByArgs("maximum number of retries exceeded")
 }
 
 // Reset is used to reset the TSO allocator.

server/tso/tso.go

@@ -19,7 +19,6 @@ import (
 	"time"
 	"unsafe"
 
-	"github.com/pingcap/errors"
 	"github.com/pingcap/failpoint"
 	"github.com/pingcap/log"
 	"github.com/tikv/pd/pkg/errs"
@@ -84,10 +83,10 @@ func (t *timestampOracle) saveTimestamp(leadership *election.Leadership, ts time
 		Then(clientv3.OpPut(key, string(data))).
 		Commit()
 	if err != nil {
-		return errors.WithStack(err)
+		return errs.ErrEtcdKVPut.Wrap(err).GenWithStackByCause()
 	}
 	if !resp.Succeeded {
-		return errors.New("save timestamp failed, maybe we lost leader")
+		return errs.ErrEtcdTxn.FastGenByArgs()
 	}
 
 	t.lastSavedTime.Store(ts)
@@ -141,7 +140,7 @@ func (t *timestampOracle) SyncTimestamp(leadership *election.Leadership) error {
 func (t *timestampOracle) ResetUserTimestamp(leadership *election.Leadership, tso uint64) error {
 	if !leadership.Check() {
 		tsoCounter.WithLabelValues("err_lease_reset_ts").Inc()
-		return errors.New("Setup timestamp failed, lease expired")
+		return errs.ErrResetUserTimestamp.FastGenByArgs("lease expired")
 	}
 	physical, _ := tsoutil.ParseTS(tso)
 	next := physical.Add(time.Millisecond)
@@ -150,12 +149,12 @@ func (t *timestampOracle) ResetUserTimestamp(leadership *election.Leadership, ts
 	// do not update
 	if typeutil.SubTimeByWallClock(next, prev.physical) <= 3*updateTimestampGuard {
 		tsoCounter.WithLabelValues("err_reset_small_ts").Inc()
-		return errors.New("the specified ts too small than now")
+		return errs.ErrResetUserTimestamp.FastGenByArgs("the specified ts too small than now")
 	}
 
 	if typeutil.SubTimeByWallClock(next, prev.physical) >= t.maxResetTSGap() {
 		tsoCounter.WithLabelValues("err_reset_large_ts").Inc()
-		return errors.New("the specified ts too large than now")
+		return errs.ErrResetUserTimestamp.FastGenByArgs("the specified ts too large than now")
 	}
 
 	save := next.Add(t.saveInterval)

tests/server/tso/tso_test.go

@@ -395,6 +395,6 @@ func (s *testFollowerTsoSuite) TestRequest(c *C) {
 	c.Assert(err, IsNil)
 	_, err = tsoClient.Recv()
 	c.Assert(err, NotNil)
-	c.Assert(strings.Contains(err.Error(), "can not get timestamp"), IsTrue)
+	c.Assert(strings.Contains(err.Error(), "generate timestamp failed"), IsTrue)
 	failpoint.Disable("github.com/tikv/pd/server/tso/skipRetryGetTS")
 }