eventsclient

README

Events client

This sample client demonstrates how to connect to a peer to receive block events. Block events come in the form of either full blocks as they have been committed to the ledger or filtered blocks (a minimal set of information about the block) which includes the transaction ids, transaction statuses, and any chaincode events associated with the transaction.

Events service interface

Starting with v1.1, two new event services are available:

service Deliver {
    // deliver first requires an Envelope of type ab.DELIVER_SEEK_INFO with Payload data as a marshaled orderer.SeekInfo message,
    // then a stream of block replies is received.
    rpc Deliver (stream common.Envelope) returns (stream DeliverResponse) {
    }
    // deliver first requires an Envelope of type ab.DELIVER_SEEK_INFO with Payload data as a marshaled orderer.SeekInfo message,
    // then a stream of **filtered** block replies is received.
    rpc DeliverFiltered (stream common.Envelope) returns (stream DeliverResponse) {
    }
}

This sample demonstrates connecting to both of these services.

General use

cd fabric/examples/events/eventsclient
go build

You will see the executable eventsclient if there are no compilation errors.

Next, to start receiving block events from a peer with TLS enabled, run the following command:

FABRIC_CFG_PATH=<path to config> CORE_PEER_LOCALMSPID=<msp-id> CORE_PEER_MSPCONFIGPATH=<path to MSP folder> ./eventsclient -channelID=<channel-id> -filtered=<true or false> -tls=true -clientKey=<path to the client key> -clientCert=<path to the client TLS certificate> -rootCert=<path to the server root CA certificate>

If the peer is not using TLS you can run:

FABRIC_CFG_PATH=<path to config> CORE_PEER_LOCALMSPID=<msp-id> CORE_PEER_MSPCONFIGPATH=<path to MSP folder> ./eventsclient -channelID=<channel-id> -filtered=<true or false> -tls=false

The peer will begin delivering block events and print the output to the console.

Example with BYFN

The events client sample can be used with TLS enabled or disabled. By default, the BYFN sample will have TLS enabled. In order to allow the events client to connect to peers created by the BYFN sample with TLS enabled, the easiest way would be to map 127.0.0.1 to the hostname of the peer that you are connecting to, such as peer0.org1.example.com. For example on *nix based systems this would be an entry in /etc/hosts file.

If you would prefer to disable TLS, you may do so by setting CORE_PEER_TLS_ENABLED=false in docker-compose-cli.yaml and base/peer-base.yaml as well as ORDERER_GENERAL_TLS_ENABLED=false inbase/docker-compose-base.yaml.

Next, run the BYFN sample.

First, generate the artifacts for BYFN:

./byfn.sh generate

Then, once the "All in one" command:

./byfn.sh up

has completed, attach the event client to peer peer0.org1.example.com by doing the following:

• If TLS is enabled:
  • to receive full blocks:

FABRIC_CFG_PATH=$GOPATH/src/github.com/hyperledger/fabric-samples/config CORE_PEER_LOCALMSPID=Org1MSP CORE_PEER_MSPCONFIGPATH=$GOPATH/src/github.com/hyperledger/fabric-samples/first-network/crypto-config/peerOrganizations/org1.example.com/peers/peer0.Org1.example.com/msp ./eventsclient -server=peer0.org1.example.com:7051 -channelID=mychannel -filtered=false -tls=true -clientKey=$GOPATH/src/github.com/hyperledger/fabric-samples/first-network/crypto-config/peerOrganizations/org1.example.com/users/Admin@Org1.example.com/tls/client.key -clientCert=$GOPATH/src/github.com/hyperledger/fabric-samples/first-network/crypto-config/peerOrganizations/org1.example.com/users/Admin@Org1.example.com/tls/client.crt -rootCert=$GOPATH/src/github.com/hyperledger/fabric-samples/first-network/crypto-config/peerOrganizations/org1.example.com/users/Admin@Org1.example.com/tls/ca.crt

• to receive filtered blocks:

FABRIC_CFG_PATH=$GOPATH/src/github.com/hyperledger/fabric-samples/config CORE_PEER_LOCALMSPID=Org1MSP CORE_PEER_MSPCONFIGPATH=$GOPATH/src/github.com/hyperledger/fabric-samples/first-network/crypto-config/peerOrganizations/org1.example.com/peers/peer0.Org1.example.com/msp ./eventsclient -server=peer0.org1.example.com:7051 -channelID=mychannel -filtered=true -tls=true -clientKey=$GOPATH/src/github.com/hyperledger/fabric-samples/first-network/crypto-config/peerOrganizations/org1.example.com/users/Admin@Org1.example.com/tls/client.key -clientCert=$GOPATH/src/github.com/hyperledger/fabric-samples/first-network/crypto-config/peerOrganizations/org1.example.com/users/Admin@Org1.example.com/tls/client.crt -rootCert=$GOPATH/src/github.com/hyperledger/fabric-samples/first-network/crypto-config/peerOrganizations/org1.example.com/users/Admin@Org1.example.com/tls/ca.crt

• If TLS is disabled:
  • to receive full blocks:

FABRIC_CFG_PATH=$GOPATH/src/github.com/hyperledger/fabric-samples/config CORE_PEER_LOCALMSPID=Org1MSP CORE_PEER_MSPCONFIGPATH=$GOPATH/src/github.com/hyperledger/fabric-samples/first-network/crypto-config/peerOrganizations/org1.example.com/peers/peer0.Org1.example.com/msp ./eventsclient -server=peer0.org1.example.com:7051 -channelID=mychannel -filtered=false -tls=false

• to receive filtered blocks:

FABRIC_CFG_PATH=$GOPATH/src/github.com/hyperledger/fabric-samples/config CORE_PEER_LOCALMSPID=Org1MSP CORE_PEER_MSPCONFIGPATH=$GOPATH/src/github.com/hyperledger/fabric-samples/first-network/crypto-config/peerOrganizations/org1.example.com/peers/peer0.Org1.example.com/msp ./eventsclient -server=peer0.org1.example.com:7051 -channelID=mychannel -filtered=true -tls=false

This work is licensed under a Creative Commons Attribution 4.0 International License.