[FAB-8395] Abstract Event Service

Defined an Event Service API and provided
an abstract implementation which may be
reused by protocol-specific implementations
(e.g. Event Hub and Deliver Service)

Change-Id: Ie8b901dfe08df20b01a38ba26c85a3a87f667a41
Signed-off-by: Bob Stasyszyn <Bob.Stasyszyn@securekey.com>

api/apifabclient/eventservice.go

@@ -0,0 +1,93 @@
+/*
+Copyright SecureKey Technologies Inc. All Rights Reserved.
+
+SPDX-License-Identifier: Apache-2.0
+*/
+
+package apifabclient
+
+import (
+	cb "github.com/hyperledger/fabric-sdk-go/third_party/github.com/hyperledger/fabric/protos/common"
+	pb "github.com/hyperledger/fabric-sdk-go/third_party/github.com/hyperledger/fabric/protos/peer"
+)
+
+// BlockEvent contains the data for the block event
+type BlockEvent struct {
+	Block *cb.Block
+}
+
+// FilteredBlockEvent contains the data for a filtered block event
+type FilteredBlockEvent struct {
+	FilteredBlock *pb.FilteredBlock
+}
+
+// TxStatusEvent contains the data for a transaction status event
+type TxStatusEvent struct {
+	TxID             string
+	TxValidationCode pb.TxValidationCode
+}
+
+// CCEvent contains the data for a chaincode event
+type CCEvent struct {
+	TxID        string
+	ChaincodeID string
+	EventName   string
+}
+
+// Registration is a handle that is returned from a successful RegisterXXXEvent.
+// This handle should be used in Unregister in order to unregister the event.
+type Registration interface{}
+
+// BlockFilter is a function that determines whether a Block event
+// should be ignored
+type BlockFilter func(block *cb.Block) bool
+
+// EventService is a service that receives events such as block, filtered block,
+// chaincode, and transaction status events.
+type EventService interface {
+	// RegisterBlockEvent registers for block events. If the caller does not have permission
+	// to register for block events then an error is returned.
+	// Note that Unregister must be called when the registration is no longer needed.
+	// - filter is an optional filter that filters out unwanted events. (Note: Only one filter may be specified.)
+	// - Returns the registration and a channel that is used to receive events. The channel
+	//   is closed when Unregister is called.
+	RegisterBlockEvent(filter ...BlockFilter) (Registration, <-chan *BlockEvent, error)
+
+	// RegisterFilteredBlockEvent registers for filtered block events.
+	// Note that Unregister must be called when the registration is no longer needed.
+	// - Returns the registration and a channel that is used to receive events. The channel
+	//   is closed when Unregister is called.
+	RegisterFilteredBlockEvent() (Registration, <-chan *FilteredBlockEvent, error)
+
+	// RegisterChaincodeEvent registers for chaincode events.
+	// Note that Unregister must be called when the registration is no longer needed.
+	// - ccID is the chaincode ID for which events are to be received
+	// - eventFilter is the chaincode event filter (regular expression) for which events are to be received
+	// - Returns the registration and a channel that is used to receive events. The channel
+	//   is closed when Unregister is called.
+	RegisterChaincodeEvent(ccID, eventFilter string) (Registration, <-chan *CCEvent, error)
+
+	// RegisterTxStatusEvent registers for transaction status events.
+	// Note that Unregister must be called when the registration is no longer needed.
+	// - txID is the transaction ID for which events are to be received
+	// - Returns the registration and a channel that is used to receive events. The channel
+	//   is closed when Unregister is called.
+	RegisterTxStatusEvent(txID string) (Registration, <-chan *TxStatusEvent, error)
+
+	// Unregister removes the given registration and closes the event channel.
+	// - reg is the registration handle that was returned from one of the Register functions
+	Unregister(reg Registration)
+}
+
+// EventClient is a client that connects to a peer and receives channel events
+// such as block, filtered block, chaincode, and transaction status events.
+type EventClient interface {
+	EventService
+
+	// Connect connects to the event server.
+	Connect() error
+
+	// Close closes the connection to the event server and releases all resources.
+	// Once this function is invoked the client may no longer be used.
+	Close()
+}

pkg/fabric-client/events/service/blockfilter/acceptanyfilter.go

@@ -0,0 +1,17 @@
+/*
+Copyright SecureKey Technologies Inc. All Rights Reserved.
+
+SPDX-License-Identifier: Apache-2.0
+*/
+
+package blockfilter
+
+import (
+	"github.com/hyperledger/fabric-sdk-go/api/apifabclient"
+	cb "github.com/hyperledger/fabric-sdk-go/third_party/github.com/hyperledger/fabric/protos/common"
+)
+
+// AcceptAny returns a block filter that accepts any block
+var AcceptAny apifabclient.BlockFilter = func(block *cb.Block) bool {
+	return true
+}

pkg/fabric-client/events/service/blockfilter/headertypefilter/headertypefilter.go

@@ -0,0 +1,51 @@
+/*
+Copyright SecureKey Technologies Inc. All Rights Reserved.
+
+SPDX-License-Identifier: Apache-2.0
+*/
+
+package headertypefilter
+
+import (
+	"github.com/hyperledger/fabric-sdk-go/api/apifabclient"
+	"github.com/hyperledger/fabric-sdk-go/pkg/logging"
+	cb "github.com/hyperledger/fabric-sdk-go/third_party/github.com/hyperledger/fabric/protos/common"
+	"github.com/hyperledger/fabric-sdk-go/third_party/github.com/hyperledger/fabric/protos/utils"
+)
+
+var logger = logging.NewLogger("eventservice/blockfilter")
+
+// New returns a block filter that filters out blocks that
+// don't contain envelopes of the given type(s)
+func New(headerTypes ...cb.HeaderType) apifabclient.BlockFilter {
+	return func(block *cb.Block) bool {
+		return hasType(block, headerTypes...)
+	}
+}
+
+func hasType(block *cb.Block, headerTypes ...cb.HeaderType) bool {
+	for i := 0; i < len(block.Data.Data); i++ {
+		env, err := utils.ExtractEnvelope(block, i)
+		if err != nil {
+			logger.Errorf("error extracting envelope from block: %s", err)
+			continue
+		}
+		payload, err := utils.ExtractPayload(env)
+		if err != nil {
+			logger.Errorf("error extracting payload from block: %s", err)
+			continue
+		}
+		chdr, err := utils.UnmarshalChannelHeader(payload.Header.ChannelHeader)
+		if err != nil {
+			logger.Errorf("error extracting channel header: %s", err)
+			continue
+		}
+		htype := cb.HeaderType(chdr.Type)
+		for _, headerType := range headerTypes {
+			if htype == headerType {
+				return true
+			}
+		}
+	}
+	return false
+}

pkg/fabric-client/events/service/blockfilter/headertypefilter/headertypefilter_test.go

@@ -0,0 +1,29 @@
+/*
+Copyright SecureKey Technologies Inc. All Rights Reserved.
+
+SPDX-License-Identifier: Apache-2.0
+*/
+
+package headertypefilter
+
+import (
+	"testing"
+
+	servicemocks "github.com/hyperledger/fabric-sdk-go/pkg/fabric-client/events/service/mocks"
+	cb "github.com/hyperledger/fabric-sdk-go/third_party/github.com/hyperledger/fabric/protos/common"
+	pb "github.com/hyperledger/fabric-sdk-go/third_party/github.com/hyperledger/fabric/protos/peer"
+)
+
+func TestHeaderTypeBlockFilter(t *testing.T) {
+	filter := New(cb.HeaderType_CONFIG, cb.HeaderType_CONFIG_UPDATE)
+
+	if !filter(servicemocks.NewBlock("somechannel", servicemocks.NewTransaction("txid", pb.TxValidationCode_VALID, cb.HeaderType_CONFIG))) {
+		t.Fatalf("expecting block filter to accept block with header type %s", cb.HeaderType_CONFIG)
+	}
+	if !filter(servicemocks.NewBlock("somechannel", servicemocks.NewTransaction("txid", pb.TxValidationCode_VALID, cb.HeaderType_CONFIG_UPDATE))) {
+		t.Fatalf("expecting block filter to accept block with header type %s", cb.HeaderType_CONFIG_UPDATE)
+	}
+	if filter(servicemocks.NewBlock("somechannel", servicemocks.NewTransaction("txid", pb.TxValidationCode_VALID, cb.HeaderType_MESSAGE))) {
+		t.Fatalf("expecting block filter to reject block with header type %s", cb.HeaderType_MESSAGE)
+	}
+}