[FAB-4472] Improve documentation for block listener

This CR improves the documentation for the block listener example,
which lacks clarity and is hard to follow.

It also cleans up a few of the printed messages in the code.

Change-Id: I65b612520f526cb5f3f0616868bac762f8719548
Signed-off-by: Will Lahti <[email protected]>

Author: wlahti

examples/events/block-listener/README.md

@@ -1,27 +1,37 @@
 # What is block-listener
-block-listener.go will connect to a peer and receive block and chaincode events (if there are chaincode events being set).
-Currently, this example only runs with TLS disabled.
+block-listener.go connects to a peer in order to receive block and chaincode
+events (if there are chaincode events being sent). Currently, this example only
+works with TLS disabled in the environment.
 
 # To Run
 ```sh
 1. go build
 
-2. ./block-listener -events-address=< event address > -events-from-chaincode=< chaincode ID > -events-mspdir=< msp directory > -events-mspid=< msp id >
+2. ./block-listener -events-address=<peer-address> -events-from-chaincode=<chaincode-id> -events-mspdir=<msp-directory> -events-mspid=<msp-id>
 ```
-Please be noted that if no msp info provided, it uses default MSP under fabric/sampleconfig.
-# Example with e2e
-Please make sure you have finished running the [e2e_cli example](https://github.com/hyperledger/fabric/tree/master/examples/e2e_cli). Before doing that, don't forget to make sure that TLS has been disabled by setting the  CORE_PEER_TLS_ENABLED=***false*** in ``docker-compose-cli.yaml``, ``base/docker-compose-base.yaml`` and ``base/peer-base.yaml``. 
+Please note that the default MSP under fabric/sampleconfig will be used if no
+MSP parameters are provided.
 
-Suppose you just finished the All-in-one:
+# Example with the e2e_cli example
+In order to use the block listener with the e2e_cli example, make sure that TLS
+has been disabled by setting CORE_PEER_TLS_ENABLED=***false*** in
+``docker-compose-cli.yaml``, ``base/docker-compose-base.yaml`` and
+``base/peer-base.yaml``.
+
+Next, run the [e2e_cli example](https://github.com/hyperledger/fabric/tree/master/examples/e2e_cli).
+
+Once the "All in one" command:
 ```sh
 ./network_setup.sh up
 ```
-Attach event client to peer peer0.org1.example.com (suppose you are running block-listener in the host environment):
+has completed, attach the event client to peer peer0.org1.example.com by doing
+the following (assuming you are running block-listener in the host environment):
 ```sh
-./block-listener -events-address=127.0.0.1:7053 -events-mspdir=<peer0.org1.example.com's msp directory > -events-mspid=Org1MSP
+./block-listener -events-address=127.0.0.1:7053 -events-mspdir=$GOPATH/src/github.com/hyperledger/fabric/examples/e2e_cli/crypto-config/peerOrganizations/org1.example.com/users/[email protected]/msp -events-mspid=Org1MSP
 ```
 
-Event client should output "Event Address: 127.0.0.1:7053" and wait for events.
+The event client should output "Event Address: 127.0.0.1:7053" and wait for
+events.
 
 Exec into the cli container:
 
@@ -30,7 +40,7 @@ docker exec -it cli bash
 ```
 Setup the environment variables for peer0.org1.example.com
 ```sh
-CORE_PEER_MSPCONFIGPATH=/opt/gopath/src/github.com/hyperledger/fabric/peer/crypto/peerOrganizations/org1.example.com/users/[email protected]/msp
+CORE_PEER_MSPCONFIGPATH=$GOPATH/src/github.com/hyperledger/fabric/peer/crypto/peerOrganizations/org1.example.com/users/[email protected]/msp
 CORE_PEER_ADDRESS=peer0.org1.example.com:7051
 CORE_PEER_LOCALMSPID="Org1MSP"
 ```
@@ -40,8 +50,8 @@ Create an invoke transaction:
 ```sh
 peer chaincode invoke -o orderer.example.com:7050 -C $CHANNEL_NAME -n mycc -c '{"Args":["invoke","a","b","10"]}'
 ```
-Now you should see the block content received in events client.
+Now you should see the block content displayed in the terminal running the block
+listener.
 
 
 <a rel="license" href="http://creativecommons.org/licenses/by/4.0/"><img alt="Creative Commons License" style="border-width:0" src="https://i.creativecommons.org/l/by/4.0/88x31.png" /></a><br />This work is licensed under a <a rel="license" href="http://creativecommons.org/licenses/by/4.0/">Creative Commons Attribution 4.0 International License</a>.
-s

examples/events/block-listener/block-listener.go

@@ -62,7 +62,7 @@ func createEventClient(eventAddress string, _ string) *adapter {
 	adapter := &adapter{notfy: done}
 	obcEHClient, _ = consumer.NewEventsClient(eventAddress, 5, adapter)
 	if err := obcEHClient.Start(); err != nil {
-		fmt.Printf("could not start chat %s\n", err)
+		fmt.Printf("could not start chat. err: %s\n", err)
 		obcEHClient.Stop()
 		return nil
 	}
@@ -149,14 +149,14 @@ func main() {
 	if mspDir == "" {
 		err := msptesttools.LoadMSPSetupForTesting()
 		if err != nil {
-			fmt.Printf("Could not initialize msp, err %s", err)
+			fmt.Printf("Could not initialize msp, err: %s\n", err)
 			os.Exit(-1)
 		}
 	} else {
 		//load msp info
 		err := mgmt.LoadLocalMsp(mspDir, nil, mspId)
 		if err != nil {
-			fmt.Printf("Could not initialize msp, err %s", err)
+			fmt.Printf("Could not initialize msp, err: %s\n", err)
 			os.Exit(-1)
 		}
 	}
@@ -188,16 +188,16 @@ func main() {
 					if txsFltr.IsInvalid(i) {
 						fmt.Println("")
 						fmt.Println("")
-						fmt.Printf("Received invalid transaction from channel %s\n", chdr.ChannelId)
+						fmt.Printf("Received invalid transaction from channel '%s'\n", chdr.ChannelId)
 						fmt.Println("--------------")
 						fmt.Printf("Transaction invalid: TxID: %s\n", chdr.TxId)
 					} else {
-						fmt.Printf("Received transaction from channel %s: \n\t[%v]\n", chdr.ChannelId, tx)
+						fmt.Printf("Received transaction from channel '%s': \n\t[%v]\n", chdr.ChannelId, tx)
 						if event, err := getChainCodeEvents(r); err == nil {
 							if len(chaincodeID) != 0 && event.ChaincodeId == chaincodeID {
 								fmt.Println("")
 								fmt.Println("")
-								fmt.Printf("Received chaincode event from channel %s\n", chdr.ChannelId)
+								fmt.Printf("Received chaincode event from channel '%s'\n", chdr.ChannelId)
 								fmt.Println("------------------------")
 								fmt.Printf("Chaincode Event:%+v\n", event)
 							}