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:
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:
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 the e2e_cli example
The events client sample can be used with TLS enabled or disabled. By default,
the e2e_cli example will have TLS enabled. In order to allow the events client
to connect to peers created by the e2e_cli example 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 e2e_cli example.
Once the “All in one” command:
./network_setup.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:
CORE_PEER_LOCALMSPID=Org1MSP CORE_PEER_MSPCONFIGPATH=$GOPATH/src/github.com/hyperledger/fabric/examples/e2e_cli/crypto-config/peerOrganizations/org1.example.com/peers/peer0.Org1.example.com/msp ./eventsclient -server=peer0.org1.example.com:7051 -channelID=mychannel -filtered=false -tls=true -clientKey=$GOPATH/src/github.com/hyperledger/fabric/examples/e2e_cli/crypto-config/peerOrganizations/org1.example.com/users/[email protected]/tls/client.key -clientCert=$GOPATH/src/github.com/hyperledger/fabric/examples/e2e_cli/crypto-config/peerOrganizations/org1.example.com/users/[email protected]/tls/client.crt -rootCert=$GOPATH/src/github.com/hyperledger/fabric/examples/e2e_cli/crypto-config/peerOrganizations/org1.example.com/users/[email protected]/tls/ca.crt
- to receive filtered blocks:
CORE_PEER_LOCALMSPID=Org1MSP CORE_PEER_MSPCONFIGPATH=$GOPATH/src/github.com/hyperledger/fabric/examples/e2e_cli/crypto-config/peerOrganizations/org1.example.com/peers/peer0.Org1.example.com/msp ./eventsclient -server=peer0.org1.example.com:7051 -channelID=mychannel -filtered=true -tls=true -clientKey=$GOPATH/src/github.com/hyperledger/fabric/examples/e2e_cli/crypto-config/peerOrganizations/org1.example.com/users/[email protected]/tls/client.key -clientCert=$GOPATH/src/github.com/hyperledger/fabric/examples/e2e_cli/crypto-config/peerOrganizations/org1.example.com/users/[email protected]/tls/client.crt -rootCert=$GOPATH/src/github.com/hyperledger/fabric/examples/e2e_cli/crypto-config/peerOrganizations/org1.example.com/users/[email protected]/tls/ca.crt
- If TLS is disabled:
- to receive full blocks:
CORE_PEER_LOCALMSPID=Org1MSP CORE_PEER_MSPCONFIGPATH=$GOPATH/src/github.com/hyperledger/fabric/examples/e2e_cli/crypto-config/peerOrganizations/org1.example.com/peers/peer0.Org1.example.com/msp ./eventsclient -server=peer0.org1.example.com:7051 -channelID=mychannel -filtered=false -tls=false
- to receive filtered blocks:
CORE_PEER_LOCALMSPID=Org1MSP CORE_PEER_MSPCONFIGPATH=$GOPATH/src/github.com/hyperledger/fabric/examples/e2e_cli/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