Back port 2023 - skip empty ledge and 2635 - RetrieveBlockByNumber (#…

…2648)

* FAB-18276 Ch.Part.API: extractSystemChannel must skip empty ledger (#2023)

- orderer/common/server/main.go extractSystemChannel() panics when
it hits an empty ledger.

- In addition this method is not covered with unit tests at all.

- Remove some dead code.

Signed-off-by: Yoav Tock <tock@il.ibm.com>
Change-Id: Ie13156784d2ec600e3f97d34f20f6836b28f7662

* Added RetrieveBlockByNumber into blockledger (#2635)

GetBlock is used for retrieving a block in ConfigBlockOrPanic
which has overhead of Iterator. It is now simplified by exposing
a BlockStore function RetrieveBlockByNumber.

Signed-off-by: Parameswaran Selvam <parselva@in.ibm.com>

Co-authored-by: Yoav Tock <tock@il.ibm.com>

common/ledger/blockledger/fileledger/impl.go

@@ -28,6 +28,7 @@ type FileLedgerBlockStore interface {
 	AddBlock(block *cb.Block) error
 	GetBlockchainInfo() (*cb.BlockchainInfo, error)
 	RetrieveBlocks(startBlockNumber uint64) (ledger.ResultsIterator, error)
+	RetrieveBlockByNumber(blockNum uint64) (*cb.Block, error)
 }
 
 // NewFileLedger creates a new FileLedger for interaction with the ledger
@@ -87,6 +88,7 @@ func (fl *FileLedger) Iterator(startPosition *ab.SeekPosition) (blockledger.Iter
 
 	iterator, err := fl.blockStore.RetrieveBlocks(startingBlockNumber)
 	if err != nil {
+		logger.Warnw("Failed to initialize block iterator", "blockNum", startingBlockNumber, "error", err)
 		return &blockledger.NotFoundErrorIterator{}, 0
 	}
 
@@ -111,3 +113,7 @@ func (fl *FileLedger) Append(block *cb.Block) error {
 	}
 	return err
 }
+
+func (fl *FileLedger) RetrieveBlockByNumber(blockNumber uint64) (*cb.Block, error) {
+	return fl.blockStore.RetrieveBlockByNumber(blockNumber)
+}

common/ledger/blockledger/ledger.go

@@ -40,6 +40,8 @@ type Reader interface {
 	Iterator(startType *ab.SeekPosition) (Iterator, uint64)
 	// Height returns the number of blocks on the ledger
 	Height() uint64
+	// retrieve blockByNumber
+	RetrieveBlockByNumber(blockNumber uint64) (*cb.Block, error)
 }
 
 // Writer allows the caller to modify the ledger

common/ledger/blockledger/util.go

@@ -10,9 +10,12 @@ import (
 	"github.com/golang/protobuf/proto"
 	cb "github.com/hyperledger/fabric-protos-go/common"
 	ab "github.com/hyperledger/fabric-protos-go/orderer"
+	"github.com/hyperledger/fabric/common/flogging"
 	"github.com/hyperledger/fabric/protoutil"
 )
 
+var logger = flogging.MustGetLogger("common.ledger.blockledger.util")
+
 var closedChan chan struct{}
 
 func init() {
@@ -95,3 +98,8 @@ func GetBlock(rl Reader, index uint64) *cb.Block {
 	}
 	return block
 }
+
+func GetBlockByNumber(rl Reader, blockNum uint64) (*cb.Block, error) {
+	logger.Debugw("Retrieving block", "blockNum", blockNum)
+	return rl.RetrieveBlockByNumber(blockNum)
+}

core/peer/deliverevents_test.go

@@ -96,6 +96,11 @@ func (m *mockReader) Height() uint64 {
 	return args.Get(0).(uint64)
 }
 
+func (m *mockReader) RetrieveBlockByNumber(blockNum uint64) (*common.Block, error) {
+	args := m.Called()
+	return args.Get(0).(*common.Block), args.Error(1)
+}
+
 // mockChainSupport
 type mockChainSupport struct {
 	mock.Mock

core/peer/peer.go

@@ -515,3 +515,7 @@ func (p *Peer) Initialize(
 		p.initChannel(cid)
 	}
 }
+
+func (flbs fileLedgerBlockStore) RetrieveBlockByNumber(blockNum uint64) (*common.Block, error) {
+	return flbs.GetBlockByNumber(blockNum)
+}