fabric监听落块事件

fabric 版本 v2.2
可以得到，区块编号，当前哈希，前块哈希

go.mod

require (
	github.com/hyperledger/fabric-gateway v1.1.0
	github.com/hyperledger/fabric-protos-go-apiv2 v0.0.0-20220615102044-467be1c7b2e7
	google.golang.org/grpc v1.47.0
)

/*
Copyright 2021 IBM All Rights Reserved.

SPDX-License-Identifier: Apache-2.0
*/

package main

import (
	"context"
	"crypto/x509"
	"fmt"
	"io/ioutil"
	"log"
	"time"

	"github.com/hyperledger/fabric-gateway/pkg/client"
	"github.com/hyperledger/fabric-gateway/pkg/identity"
	"google.golang.org/grpc"
	"google.golang.org/grpc/credentials"
)

const (
	mspID        = "Org1MSP"
	cryptoPath   = "../bcb-cc-mon/config/ysjg1-p0-u152302"
	certPath     = cryptoPath + "/cert.pem"
	keyPath      = cryptoPath + "/priv_sk"
	tlsCertPath  = cryptoPath + "/ca.crt"
	peerEndpoint = "peer0.org1.example.com:7051"
	gatewayPeer  = "peer0.org1.example.com"
	channelName  = "chl-02"
)

func main() {
	log.Println("============ application-golang starts ============")

	// The gRPC client connection should be shared by all Gateway connections to this endpoint
	clientConnection := newGrpcConnection()
	defer clientConnection.Close()

	id := newIdentity()
	sign := newSign()

	// Create a Gateway connection for a specific client identity
	gateway, err := client.Connect(
		id,quire (
	github.com/hyperledger/fabric-gateway v1.1.0
	github.com/hyperledger/fabric-protos-go-apiv2 v0.0.0-20220615102044-467be1c7b2e7
	google.golang.org/grpc v1.47.0
)
		client.WithSign(sign),
		client.WithClientConnection(clientConnection),
		// Default timeouts for different gRPC calls
		client.WithEvaluateTimeout(5*time.Second),
		client.WithEndorseTimeout(15*time.Second),
		client.WithSubmitTimeout(5*time.Second),
		client.WithCommitStatusTimeout(1*time.Minute),
	)
	if err != nil {
		panic(err)
	}
	defer gateway.Close()

	network := gateway.GetNetwork(channelName)

	ctx, cannel := context.WithCancel(context.Background())
	defer cannel()

	events, err := network.BlockEvents(ctx, client.WithStartBlock(10))
	if err != nil {
		panic(err)
	}
	for event := range events {
		fmt.Printf("---> 区块编号: %v\n", event.GetHeader().GetNumber())
	}
}

// newGrpcConnection creates a gRPC connection to the Gateway server.
func newGrpcConnection() *grpc.ClientConn {
	certificate, err := loadCertificate(tlsCertPath)
	if err != nil {
		panic(err)
	}

	certPool := x509.NewCertPool()
	certPool.AddCert(certificate)
	transportCredentials := credentials.NewClientTLSFromCert(certPool, gatewayPeer)

	connection, err := grpc.Dial(peerEndpoint, grpc.WithTransportCredentials(transportCredentials))
	if err != nil {
		panic(fmt.Errorf("failed to create gRPC connection: %w", err))
	}

	return connection
}

// newIdentity creates a client identity for this Gateway connection using an X.509 certificate.
func newIdentity() *identity.X509Identity {
	certificate, err := loadCertificate(certPath)
	if err != nil {
		panic(err)
	}

	id, err := identity.NewX509Identity(mspID, certificate)
	if err != nil {
		panic(err)
	}

	return id
}

func loadCertificate(filename string) (*x509.Certificate, error) {
	certificatePEM, err := ioutil.ReadFile(filename)
	if err != nil {
		return nil, fmt.Errorf("failed to read certificate file: %w", err)
	}
	return identity.CertificateFromPEM(certificatePEM)
}

// newSign creates a function that generates a digital signature from a message digest using a private key.
func newSign() identity.Sign {quire (
	github.com/hyperledger/fabric-gateway v1.1.0
	github.com/hyperledger/fabric-protos-go-apiv2 v0.0.0-20220615102044-467be1c7b2e7
	google.golang.org/grpc v1.47.0
)
	//files, err := ioutil.ReadDir(keyPath)
	//if err != nil {
	//panic(fmt.Errorf("failed to read private key directory: %w", err))
	//}
	//privateKeyPEM, err := ioutil.ReadFile(path.Join(keyPath, files[0].Name()))
	privateKeyPEM, err := ioutil.ReadFile(keyPath)
	if err != nil {
		panic(fmt.Errorf("failed to read private key file: %w", err))
	}

	privateKey, err := identity.PrivateKeyFromPEM(privateKeyPEM)
	if err != nil {
		panic(err)
	}

	sign, err := identity.NewPrivateKeySign(privateKey)
	if err != nil {
		panic(err)
	}

	return sign
}