[FAB-3493] Fix LAST_CONFIG on new channels

The fix submitted in [1] works in that it delivers what we were looking
for (a pointer to the last config block) but is based on an incorrect
assumption: that the sequence number of the genesis block of a
non-system channel should be zero.

I assumed that should be the case, what with it being the genesis block
and all, but this breaks the abstraction that the config update
framework introduces. This changeset introduces the right fix. Thanks to
Jason Yellick for pointing this out.

[1] https://gerrit.hyperledger.org/r/#/c/8825/

Change-Id: I61ef2825c4cfe55495a4d81cff759fd6c340c191
Signed-off-by: Kostas Christidis <kostas@christidis.io>

orderer/common/broadcast/broadcast.go

@@ -162,7 +162,7 @@ func (bh *handlerImpl) Handle(srv ab.AtomicBroadcast_BroadcastServer) error {
 		}
 
 		if logger.IsEnabledFor(logging.DEBUG) {
-			logger.Debugf("Broadcast has successfully enqueued message of type %d for chain %s", chdr.Type, chdr.ChannelId)
+			logger.Debugf("Broadcast has successfully enqueued message of type %s for chain %s", cb.HeaderType_name[chdr.Type], chdr.ChannelId)
 		}
 
 		err = srv.Send(&ab.BroadcastResponse{Status: cb.Status_SUCCESS})

orderer/multichain/chainsupport.go

@@ -231,6 +231,7 @@ func (cs *chainSupport) addLastConfigSignature(block *cb.Block) {
 	}
 
 	lastConfigValue := utils.MarshalOrPanic(&cb.LastConfig{Index: cs.lastConfig})
+	logger.Debugf("[channel: %s] About to write block, setting its LAST_CONFIG to %d", cs.ChainID(), cs.lastConfig)
 
 	lastConfigSignature.Signature = utils.SignOrPanic(cs.signer, util.ConcatenateBytes(lastConfigValue, lastConfigSignature.SignatureHeader, block.Header.Bytes()))
 
@@ -257,6 +258,8 @@ func (cs *chainSupport) WriteBlock(block *cb.Block, committers []filter.Committe
 	if err != nil {
 		logger.Panicf("[channel: %s] Could not append block: %s", cs.ChainID(), err)
 	}
+	logger.Debugf("[channel: %s] Wrote block %d", cs.ChainID(), block.GetHeader().Number)
+
 	return block
 }
 

orderer/multichain/manager.go

@@ -187,6 +187,11 @@ func (ml *multiLedger) newChain(configtx *cb.Envelope) {
 
 	logger.Infof("Created and starting new chain %s", chainID)
 
+	cs.lastConfigSeq = cs.Sequence()
+	// The sequence number on the genesis block of the system channel will be 0.
+	// The sequence number on the genesis block of every non-system channel will be 1.
+	logger.Debugf("[channel: %s] Last config set to %d", chainID, cs.lastConfigSeq)
+
 	newChains[string(chainID)] = cs
 	cs.start()
 

orderer/multichain/manager_test.go

@@ -21,6 +21,7 @@ import (
 	"testing"
 	"time"
 
+	"github.com/golang/protobuf/proto"
 	"github.com/hyperledger/fabric/common/configtx"
 	genesisconfig "github.com/hyperledger/fabric/common/configtx/tool/localconfig"
 	"github.com/hyperledger/fabric/common/configtx/tool/provisional"
@@ -235,15 +236,17 @@ func TestSignatureFilter(t *testing.T) {
 
 // This test brings up the entire system, with the mock consenter, including the broadcasters etc. and creates a new chain
 func TestNewChain(t *testing.T) {
+	expectedLastConfigBlockNumber := uint64(0)
+	expectedLastConfigSeq := uint64(1)
+	newChainID := "TestNewChain"
+
 	lf, rl := NewRAMLedgerAndFactory(10)
 
 	consenters := make(map[string]Consenter)
 	consenters[conf.Orderer.OrdererType] = &mockConsenter{}
 
 	manager := NewManagerImpl(lf, consenters, mockCrypto())
 
-	newChainID := "TestNewChain"
-
 	envConfigUpdate, err := configtx.MakeChainCreationTransaction(newChainID, genesisconfig.SampleConsortiumName, mockSigningIdentity)
 	assert.NoError(t, err, "Constructing chain creation tx")
 
@@ -252,6 +255,7 @@ func TestNewChain(t *testing.T) {
 
 	configEnv, err := cm.ProposeConfigUpdate(envConfigUpdate)
 	assert.NoError(t, err, "Proposing initial update")
+	assert.Equal(t, expectedLastConfigSeq, configEnv.GetConfig().Sequence, "Sequence of config envelope for new channel should always be set to %d", expectedLastConfigSeq)
 
 	ingressTx, err := utils.CreateSignedEnvelope(cb.HeaderType_CONFIG, newChainID, mockCrypto(), configEnv, msgVersion, epoch)
 	assert.NoError(t, err, "Creating ingresstx")
@@ -260,6 +264,7 @@ func TestNewChain(t *testing.T) {
 
 	chainSupport, ok := manager.GetChain(manager.SystemChannelID())
 	assert.True(t, ok, "Could not find system channel")
+
 	chainSupport.Enqueue(wrapped)
 
 	it, _ := rl.Iterator(&ab.SeekPosition{Type: &ab.SeekPosition_Specified{Specified: &ab.SeekSpecified{Number: 1}}})
@@ -300,6 +305,7 @@ func TestNewChain(t *testing.T) {
 		if status != cb.Status_SUCCESS {
 			t.Fatalf("Could not retrieve new chain genesis block")
 		}
+		testLastConfigBlockNumber(t, block, expectedLastConfigBlockNumber)
 		if len(block.Data.Data) != 1 {
 			t.Fatalf("Should have had only one message in the new genesis block")
 		}
@@ -315,6 +321,7 @@ func TestNewChain(t *testing.T) {
 		if status != cb.Status_SUCCESS {
 			t.Fatalf("Could not retrieve block on new chain")
 		}
+		testLastConfigBlockNumber(t, block, expectedLastConfigBlockNumber)
 		for i := 0; i < int(conf.Orderer.BatchSize.MaxMessageCount); i++ {
 			if !reflect.DeepEqual(utils.ExtractEnvelopeOrPanic(block, i), messages[i]) {
 				t.Errorf("Block contents wrong at index %d in new chain", i)
@@ -324,3 +331,13 @@ func TestNewChain(t *testing.T) {
 		t.Fatalf("Block 1 not produced after timeout on new chain")
 	}
 }
+
+func testLastConfigBlockNumber(t *testing.T, block *cb.Block, expectedBlockNumber uint64) {
+	metadataItem := &cb.Metadata{}
+	err := proto.Unmarshal(block.Metadata.Metadata[cb.BlockMetadataIndex_LAST_CONFIG], metadataItem)
+	assert.NoError(t, err, "Block should carry LAST_CONFIG metadata item")
+	lastConfig := &cb.LastConfig{}
+	err = proto.Unmarshal(metadataItem.Value, lastConfig)
+	assert.NoError(t, err, "LAST_CONFIG metadata item should carry last config value")
+	assert.Equal(t, expectedBlockNumber, lastConfig.Index, "LAST_CONFIG value should point to last config block")
+}