Overview

This section illustrates a process to orchestrate a Hyperledger Fabric network via a simple two-organisations network demonstrator. The demonstrator uses a combination of Hyperledger Fabric command line (CLI) tools to demonstrate a process. Command lines tools provide the ability to the process under the hood.

The demonstrator has been verified to work on macOS these versions of Hyperledger Fabric components:

Scenario

Imagine a scenario where you are tasked with orchestrating a two-organisation network with one orderer node operating in solo mode. Each organisation is assigned a Hyperledger Fabric Certificate Authority (CA), a peer node (anchor, endorser and committer combined) and a CLI client node (to enable user interact with peer node).

Having created the network, you are task with a installing and instantiating a chaincode (named minimalcc). The chaincode contains logic to transfer values between two personas (Paul and John). Where initially, Paul is assigned 10 units and John assigned 20 units of some value.

The process involve org1 who is tasked with create an initial channel for the whole network. The channel is configure to facilitate transactions betweenorg1 and org2 only. Please refer to the topic crypto-configtx where the process of configuring Hyperledger Fabric channel is discussed.

org1 and org2 are responsible to for installing chaincodes in their own peer nodes. In this particular scenario, org1 is responsible for instantiating the chaincode. org2 is reponsible for installing the chaincode only.

org1 and org2 interacts with their respective installed chaincode by invoking and querying. Whilst each organisation interacts with its own node, you will see that both nodes will produce same result.

NOTE: if you are a chaincode developer and wanting to test out your chaincode, you could clone this folder and work with this.

How to use this demonstrator

The demonstrator is hardcoded to follow the scenario described above out-of-the-box.

STEP 1 - Open a bash terminal and clone the repo https://github.com/fabric-devkit/core-platform. Examine the docker-compose.yaml (this shows the relationship between the orders, peer nodes and cli nodes) and scripts (these are bash scripts showing steps to configure and interact with the network using cli tools).

STEP 2 - Navigate to the folder twoorg-dev.

STEP 3 - Run the command ./fabricOps.sh artefacts. This creates the necessary crytographic and channel configuration assets (i.e. genesis nodes, etc).

STEP 4 - Run the command ./fabricOps.sh network start to start-up a pre-configure network.

STEP 5 - Run the command ./fabricOps.sh cli org1 to give you access to the cli tool belonging to org1. You will see the terminal that looks similar to this:

root@311ebdd409fc:/opt/gopath/src/github.com/hyperledger/fabric#

STEP 4 - In org1 cli terminal, run the command ./scripts/createChan.sh, and if you get a result similar to this:

root@311ebdd409fc:/opt/gopath/src/github.com/hyperledger/fabric# ./scripts/createChan.sh
........
........
2019-10-20 14:28:39.845 UTC [channelCmd] executeJoin -> INFO 040 Successfully submitted proposal to join channel

This means org1 peer has created a channel named mychannel and joined it.

STEP 5 - In org1 cli terminal, run the command ./scripts/installCC.sh to install the chaincode name minimalcc in org1 peer node. Watch for a message: Installed remotely response:<status:200 payload:"OK" > to be confident of success.

STEP 6 - In org1 cli terminal, run the command ./scripts/instantiateCC.sh to instantiate the chaincode – i.e. initialise the world state with Paul 10 units and John 20 units. It make take some time to complete this the process.

STEP 7 - In org1 cli terminal, run the command ./scripts/query.sh Paul and you will see an indication stating Paul has 10 units.

STEP 8 - Run the command exit to leave org1 cli terminal.

STEP 9 - Run the command ./fabricOps.sh cli org2 to give you access to org2 cli terminal.

STEP 10 - In org2 cli terminal, run the command ./scripts/joinChan.sh to join org2 peer node to mychannel.

STEP 11 - In org2 cli terminal, run the command ./scripts/installCC.sh in org2 peer node.

STEP 12 - In org2 cli terminal, run the command ./scripts/query.sh John to show initial value of 20 assigned to John.

When you have completed these steps you will have a fully initialise network.

NOTE: You will have noticed that there is a script invoke.sh that simulate a hardcoded payment transaction from the persona John to Paul for 1 unit. This does not have an effect on the network – i.e. reach a consensus between org1 and org2 nodes that payment has occurred between the two personas. So neither nodes will have updated their world state. The cli command peer chaincode invoke only runs a simulation of the chaincode but it does not commit the result to the world state. You can use this script to help you debug the chaincode without impacting the network state.

Copyright Notice

Copyright (c) 2019. The Fabric-DevKit Authors. All rights reserved. SPDX-License-Identifier: Apache-2.0