Implement GetTxTimestamp() for chaincode stub

This change sets the transaction timestamp in the proposal's
ChannelHeader and then implements stub.GetTxTimestamp() to retrieve
that timestamp.

https://jira.hyperledger.org/browse/FAB-2701

Change-Id: I95ed9004294a80d1e277dae67970a9735d9cb71b
Signed-off-by: Will Lahti <wtlahti@us.ibm.com>

core/chaincode/shim/chaincode.go

@@ -558,11 +558,20 @@ func (stub *ChaincodeStub) GetArgsSlice() ([]byte, error) {
 	return res, nil
 }
 
-// GetTxTimestamp returns transaction created timestamp, which is currently
-// taken from the peer receiving the transaction. Note that this timestamp
-// may not be the same with the other peers' time.
+// GetTxTimestamp returns the timestamp when the transaction was created. This
+// is taken from the transaction ChannelHeader, so it will be the same across
+// all endorsers.
 func (stub *ChaincodeStub) GetTxTimestamp() (*timestamp.Timestamp, error) {
-	return nil, nil
+	hdr, err := utils.GetHeader(stub.proposal.Header)
+	if err != nil {
+		return nil, err
+	}
+	chdr, err := utils.UnmarshalChannelHeader(hdr.ChannelHeader)
+	if err != nil {
+		return nil, err
+	}
+
+	return chdr.GetTimestamp(), nil
 }
 
 // ------------- ChaincodeEvent API ----------------------

core/chaincode/shim/interfaces.go

@@ -118,9 +118,9 @@ type ChaincodeStubInterface interface {
 	// GetArgsSlice returns the arguments to the stub call as a byte array
 	GetArgsSlice() ([]byte, error)
 
-	// GetTxTimestamp returns transaction created timestamp, which is currently
-	// taken from the peer receiving the transaction. Note that this timestamp
-	// may not be the same with the other peers' time.
+	// GetTxTimestamp returns the timestamp when the transaction was created. This
+	// is taken from the transaction ChannelHeader, so it will be the same across
+	// all endorsers.
 	GetTxTimestamp() (*timestamp.Timestamp, error)
 
 	// SetEvent saves the event to be sent when a transaction is made part of a block

core/chaincode/shim/mockstub.go

@@ -25,6 +25,7 @@ import (
 	"strings"
 
 	"github.com/golang/protobuf/ptypes/timestamp"
+	"github.com/hyperledger/fabric/common/util"
 	pb "github.com/hyperledger/fabric/protos/peer"
 	"github.com/op/go-logging"
 )
@@ -57,6 +58,8 @@ type MockStub struct {
 	// stores a transaction uuid while being Invoked / Deployed
 	// TODO if a chaincode uses recursion this may need to be a stack of TxIDs or possibly a reference counting map
 	TxID string
+
+	TxTimestamp *timestamp.Timestamp
 }
 
 func (stub *MockStub) GetTxID() string {
@@ -92,6 +95,7 @@ func (stub *MockStub) GetFunctionAndParameters() (function string, params []stri
 // MockStub doesn't support concurrent transactions at present.
 func (stub *MockStub) MockTransactionStart(txid string) {
 	stub.TxID = txid
+	stub.setTxTimestamp(util.CreateUtcTimestamp())
 }
 
 // End a mocked transaction, clearing the UUID.
@@ -270,9 +274,15 @@ func (stub *MockStub) GetArgsSlice() ([]byte, error) {
 	return nil, nil
 }
 
-// Not implemented
+func (stub *MockStub) setTxTimestamp(time *timestamp.Timestamp) {
+	stub.TxTimestamp = time
+}
+
 func (stub *MockStub) GetTxTimestamp() (*timestamp.Timestamp, error) {
-	return nil, nil
+	if stub.TxTimestamp == nil {
+		return nil, errors.New("TxTimestamp not set.")
+	}
+	return stub.TxTimestamp, nil
 }
 
 // Not implemented

core/chaincode/shim/mockstub_test.go

@@ -219,3 +219,15 @@ func TestGetStateByPartialCompositeKeyCollision(t *testing.T) {
 		t.FailNow()
 	}
 }
+
+func TestGetTxTimestamp(t *testing.T) {
+	stub := NewMockStub("GetTxTimestamp", nil)
+	stub.MockTransactionStart("init")
+
+	timestamp, err := stub.GetTxTimestamp()
+	if timestamp == nil || err != nil {
+		t.FailNow()
+	}
+
+	stub.MockTransactionEnd("init")
+}

protos/utils/proputils.go

@@ -27,6 +27,7 @@ import (
 	"github.com/golang/protobuf/proto"
 	"github.com/hyperledger/fabric/bccsp"
 	"github.com/hyperledger/fabric/bccsp/factory"
+	"github.com/hyperledger/fabric/common/util"
 	"github.com/hyperledger/fabric/core/chaincode/platforms"
 	"github.com/hyperledger/fabric/core/crypto/primitives"
 	"github.com/hyperledger/fabric/protos/common"
@@ -361,9 +362,12 @@ func CreateChaincodeProposalWithTxIDNonceAndTransient(txid string, typ common.He
 	// get a more appropriate mechanism to handle it in.
 	var epoch uint64 = 0
 
+	timestamp := util.CreateUtcTimestamp()
+
 	hdr := &common.Header{ChannelHeader: MarshalOrPanic(&common.ChannelHeader{
 		Type:      int32(typ),
 		TxId:      txid,
+		Timestamp: timestamp,
 		ChannelId: chainID,
 		Extension: ccHdrExtBytes,
 		Epoch:     epoch}),