This code pattern illustrates the Hyperledger Fabric EVM which allows developers to create blockchain application with EVM (Ethereum Virtual Machine) smart contract languages such as Solidity. This smart contract is deployed onto the EVM chaincode running on the Fabric peers. This pattern shows how a user, such as a member or partner for our loyalty points use case, can interact with the smart contract through Fab3, a proxy to the fabric network. Fab3 allows for using the Ethereum web3.js library for interacting with the EVM in the Fabric network.
A Node.js web application demonstrates a loyalty points contract by allowing users to register as members or partners on the network. The members can then perform transactions to earn or redeem points with the partners on the network, which are all recorded on the ledger. The decentralized application (DApp) acts a convenient way for users to submit and query transactions associated with a deployed smart contract.
This code pattern is for developers looking to create blockchain applications with Hyperledger Fabric by using Solidity smart contracts and the web3.js library. When the reader has completed this code pattern, they will understand how to:
- Deploy an instance of Hyperledger Fabric locally with the EVM chaincode
- Start a Fab3 instance to interact with the Fabric network
- Interact with the Solidity smart contract using the web3 library
- Build a Node.js blockchain web application with the web3 library
Note The blockchain network can have multiple members and partners
- Partner would access the loyalty points dapp to register on the network and view their portal.
- The loyalty points dapp built using the ethereum web3.js library makes use of Fab3 setup for the partner.
- This Fab3 will allow the partner to interact with the blockchain network
- Member would access the loyalty points dapp to register on the network and view their portal. Through their portal, they can perform transactions to earn or redeem points from the partners on the network, and view all transactions.
- This would use the same loyalty points dapp built using the ethereum web3.js library, using the Fab3 setup for the member.
- This Fab3 will allow the member to interact with the blockchain network
- Hyperledger Fabric v1.3 Hyperledger Fabric is a platform for distributed ledger solutions, underpinned by a modular architecture delivering high degrees of confidentiality, resiliency, flexibility and scalability
- Hyperledger Fabric EVM chaincode This project enables one to deploy Ethereum smart contracts written in an EVM compatible language such as Solidity or Vyper on the Hyperledger Fabric permissioned blockchain platform.
- Ethereum web3.js web3.js is a library which allow you to interact with a local or remote nodes that implement the Ethereum JSON RPC API, using a HTTP or IPC connection.
- Solidity Solidity is a contract-oriented, high-level language for implementing smart contracts
- Nodejs Node.js is an open-source, cross-platform JavaScript run-time environment that executes JavaScript code server-side
- Bootstrap Bootstrap is an open source toolkit for developing with HTML, CSS, and JS
- Go (version 1.11.1)
- Docker (version 17.06.2-ce or greater)
- Node (version 8.9.x or greater)
- npm (version 5.6.0)
- Deploy Hyperledger Fabric locally with EVM chaincode
- Setup Fab3
- Deploy the smart contract
- Setup a second Fab3
- Run the web application
In this step, we will setup fabric locally using docker containers, install the EVM chaincode (EVMCC) and instantiate the EVMCC on our fabric peers. This step uses the hyperledger fabric-sample repo to deploy fabric locally and the fabric-chaincode-evm repo for the EVMCC, Fab3 and Fab3. This step follows the fabric-chaincode-evm tutorial closely.
This will remove all your docker containers and images!
docker stop $(docker ps -a -q)
docker rm $(docker ps -a -q)
docker rmi $(docker images -q) -f
Make sure to set GOPATH to your go installation
export GOPATH=$HOME/go
Clone the fabric-samples repo in your GOPATH/src/github.com/hyperledger directory:
cd $GOPATH/src/github.com/hyperledger/
git clone https://github.com/hyperledger/fabric-samples.git
Checkout release-1.3
cd fabric-samples
git checkout release-1.3
Download the docker images
./scripts/bootstrap.sh
Clone the fabric-chaincode-evm repo in your GOPATH directory.
cd $GOPATH/src/github.com/hyperledger/
git clone https://github.com/hyperledger/fabric-chaincode-evm
Now navigate back to your fabric-samples folder. Here we will use first-network to launch the network.
cd $GOPATH/src/github.com/hyperledger/fabric-samples/first-network
Update the docker-compose-cli.yaml with the volumes to include the fabric-chaincode-evm.
cli:
volumes:
- ./../../fabric-chaincode-evm:/opt/gopath/src/github.com/hyperledger/fabric-chaincode-evm
Generate certificates and bring up the network
./byfn.sh generate
./byfn.sh up
Navigate into the cli docker container
docker exec -it cli bash
If successful, you should see the following prompt
root@0d78bb69300d:/opt/gopath/src/github.com/hyperledger/fabric/peer#
To change which peer is targeted change the following environment variables:
export CORE_PEER_MSPCONFIGPATH=/opt/gopath/src/github.com/hyperledger/fabric/peer/crypto/peerOrganizations/org1.example.com/users/Admin@org1.example.com/msp
export CORE_PEER_ADDRESS=peer0.org1.example.com:7051
export CORE_PEER_LOCALMSPID="Org1MSP"
export CORE_PEER_TLS_ROOTCERT_FILE=/opt/gopath/src/github.com/hyperledger/fabric/peer/crypto/peerOrganizations/org1.example.com/peers/peer0.org1.example.com/tls/ca.crt
Next install the EVM chaincode on all the peers
peer chaincode install -n evmcc -l golang -v 0 -p github.com/hyperledger/fabric-chaincode-evm/evmcc
Instantiate the chaincode:
peer chaincode instantiate -n evmcc -v 0 -C mychannel -c '{"Args":[]}' -o orderer.example.com:7050 --tls --cafile /opt/gopath/src/github.com/hyperledger/fabric/peer/crypto/ordererOrganizations/example.com/orderers/orderer.example.com/msp/tlscacerts/tlsca.example.com-cert.pem
Great. You are now ready to setup Fab3.
In a terminal, execute the following to set certain environment variables required for setting up Fab3.
export FABPROXY_CONFIG=${GOPATH}/src/github.com/hyperledger/fabric-chaincode-evm/examples/first-network-sdk-config.yaml # Path to a compatible Fabric SDK Go config file
export FABPROXY_USER=User1 # User identity being used for the proxy (Matches the users names in the crypto-config directory specified in the config)
export FABPROXY_ORG=Org1 # Organization of the specified user
export FABPROXY_CHANNEL=mychannel # Channel to be used for the transactions
export FABPROXY_CCID=evmcc # ID of the EVM Chaincode deployed in your fabric network
export PORT=5000 # Port the proxy will listen on. If not provided default is 5000.
Navigate to the fabric-chaincode-evm cloned repo:
cd $GOPATH/src/github.com/hyperledger/fabric-chaincode-evm/
Run the following to build the fab proxy
go build -o fab3 ./fabproxy/cmd
You can then run the proxy:
./fab3
This will start Fab3 at http://localhost:5000
Next, we'll install web3 and use this library to deploy the smart contract. In a new terminal, install web3 by running the following:
npm install web3@0.20.2
Now we'll enter node console to set up our web3.
node
Assign Web3 library and use the fab proxy as provider
Web3 = require('web3')
web3 = new Web3(new Web3.providers.HttpProvider('http://localhost:5000'))
Check to see you account information
web3.eth.accounts
You should see something like:
[ '0x2c045d4565e31cef1f6cd7368c3436a79f1cea4f' ]
Assign this account as defaultAccount
web3.eth.defaultAccount = web3.eth.accounts[0]
Now we are ready to deploy the LoyaltyPoints contract. We will assign the contract's ABI and byte code. These can be generated through remix (http://remix.ethereum.org)
Assign the abi of the contract:
Assign Loyalty ABI
LoyaltyABI = [ { "constant": true, "inputs": [ { "name": "", "type": "address" } ], "name": "members", "outputs": [ { "name": "memberAddress", "type": "address" }, { "name": "firstName", "type": "string" }, { "name": "lastName", "type": "string" }, { "name": "email", "type": "string" }, { "name": "points", "type": "uint256" }, { "name": "isRegistered", "type": "bool" } ], "payable": false, "stateMutability": "view", "type": "function" }, { "constant": true, "inputs": [], "name": "transactionsInfoLength", "outputs": [ { "name": "", "type": "uint256" } ], "payable": false, "stateMutability": "view", "type": "function" }, { "constant": false, "inputs": [ { "name": "_firstName", "type": "string" }, { "name": "_lastName", "type": "string" }, { "name": "_email", "type": "string" } ], "name": "registerMember", "outputs": [], "payable": false, "stateMutability": "nonpayable", "type": "function" }, { "constant": false, "inputs": [ { "name": "_points", "type": "uint256" }, { "name": "_partnerAddress", "type": "address" } ], "name": "usePoints", "outputs": [], "payable": false, "stateMutability": "nonpayable", "type": "function" }, { "constant": false, "inputs": [ { "name": "_points", "type": "uint256" }, { "name": "_partnerAddress", "type": "address" } ], "name": "earnPoints", "outputs": [], "payable": false, "stateMutability": "nonpayable", "type": "function" }, { "constant": true, "inputs": [ { "name": "", "type": "uint256" } ], "name": "transactionsInfo", "outputs": [ { "name": "points", "type": "uint256" }, { "name": "transactionType", "type": "uint8" }, { "name": "memberAddress", "type": "address" }, { "name": "partnerAddress", "type": "address" } ], "payable": false, "stateMutability": "view", "type": "function" }, { "constant": true, "inputs": [ { "name": "", "type": "address" } ], "name": "partners", "outputs": [ { "name": "partnerAddress", "type": "address" }, { "name": "name", "type": "string" }, { "name": "isRegistered", "type": "bool" } ], "payable": false, "stateMutability": "view", "type": "function" }, { "constant": true, "inputs": [ { "name": "", "type": "uint256" } ], "name": "partnersInfo", "outputs": [ { "name": "partnerAddress", "type": "address" }, { "name": "name", "type": "string" }, { "name": "isRegistered", "type": "bool" } ], "payable": false, "stateMutability": "view", "type": "function" }, { "constant": true, "inputs": [], "name": "partnersInfoLength", "outputs": [ { "name": "", "type": "uint256" } ], "payable": false, "stateMutability": "view", "type": "function" }, { "constant": false, "inputs": [ { "name": "_name", "type": "string" } ], "name": "registerPartner", "outputs": [], "payable": false, "stateMutability": "nonpayable", "type": "function" } ]
Next assign the evm complied byte code:
LoyaltyByteCode = `608060405234801561001057600080fd5b50611c1e806100206000396000f3006080604052600436106100a4576000357c0100000000000000000000000000000000000000000000000000000000900463ffffffff16806308ae4b0c146100a957806309b569111461028257806349c81cc5146102ad5780634d11b26b146103a257806360bd2683146103ef578063674c70991461043c57806395c33652146104f8578063d5763aea146105f2578063e6a14a7c146106d6578063e7a96e0c14610701575b600080fd5b3480156100b557600080fd5b506100ea600480360381019080803573ffffffffffffffffffffffffffffffffffffffff16906020019092919050505061076a565b604051808773ffffffffffffffffffffffffffffffffffffffff1673ffffffffffffffffffffffffffffffffffffffff16815260200180602001806020018060200186815260200185151515158152602001848103845289818151815260200191508051906020019080838360005b83811015610174578082015181840152602081019050610159565b50505050905090810190601f1680156101a15780820380516001836020036101000a031916815260200191505b50848103835288818151815260200191508051906020019080838360005b838110156101da5780820151818401526020810190506101bf565b50505050905090810190601f1680156102075780820380516001836020036101000a031916815260200191505b50848103825287818151815260200191508051906020019080838360005b83811015610240578082015181840152602081019050610225565b50505050905090810190601f16801561026d5780820380516001836020036101000a031916815260200191505b50995050505050505050505060405180910390f35b34801561028e57600080fd5b5061029761099b565b6040518082815260200191505060405180910390f35b3480156102b957600080fd5b506103a0600480360381019080803590602001908201803590602001908080601f0160208091040260200160405190810160405280939291908181526020018383808284378201915050505050509192919290803590602001908201803590602001908080601f0160208091040260200160405190810160405280939291908181526020018383808284378201915050505050509192919290803590602001908201803590602001908080601f01602080910402602001604051908101604052809392919081815260200183838082843782019150505050505091929192905050506109a8565b005b3480156103ae57600080fd5b506103ed60048036038101908080359060200190929190803573ffffffffffffffffffffffffffffffffffffffff169060200190929190505050610cd3565b005b3480156103fb57600080fd5b5061043a60048036038101908080359060200190929190803573ffffffffffffffffffffffffffffffffffffffff16906020019092919050505061114b565b005b34801561044857600080fd5b506104676004803603810190808035906020019092919050505061150b565b6040518085815260200184600181111561047d57fe5b60ff1681526020018373ffffffffffffffffffffffffffffffffffffffff1673ffffffffffffffffffffffffffffffffffffffff1681526020018273ffffffffffffffffffffffffffffffffffffffff1673ffffffffffffffffffffffffffffffffffffffff16815260200194505050505060405180910390f35b34801561050457600080fd5b50610539600480360381019080803573ffffffffffffffffffffffffffffffffffffffff169060200190929190505050611597565b604051808473ffffffffffffffffffffffffffffffffffffffff1673ffffffffffffffffffffffffffffffffffffffff1681526020018060200183151515158152602001828103825284818151815260200191508051906020019080838360005b838110156105b557808201518184015260208101905061059a565b50505050905090810190601f1680156105e25780820380516001836020036101000a031916815260200191505b5094505050505060405180910390f35b3480156105fe57600080fd5b5061061d60048036038101908080359060200190929190505050611686565b604051808473ffffffffffffffffffffffffffffffffffffffff1673ffffffffffffffffffffffffffffffffffffffff1681526020018060200183151515158152602001828103825284818151815260200191508051906020019080838360005b8381101561069957808201518184015260208101905061067e565b50505050905090810190601f1680156106c65780820380516001836020036101000a031916815260200191505b5094505050505060405180910390f35b3480156106e257600080fd5b506106eb611784565b6040518082815260200191505060405180910390f35b34801561070d57600080fd5b50610768600480360381019080803590602001908201803590602001908080601f0160208091040260200160405190810160405280939291908181526020018383808284378201915050505050509192919290505050611791565b005b60006020528060005260406000206000915090508060000160009054906101000a900473ffffffffffffffffffffffffffffffffffffffff1690806001018054600181600116156101000203166002900480601f01602080910402602001604051908101604052809291908181526020018280546001816001161561010002031660029004801561083c5780601f106108115761010080835404028352916020019161083c565b820191906000526020600020905b81548152906001019060200180831161081f57829003601f168201915b505050505090806002018054600181600116156101000203166002900480601f0160208091040260200160405190810160405280929190818152602001828054600181600116156101000203166002900480156108da5780601f106108af576101008083540402835291602001916108da565b820191906000526020600020905b8154815290600101906020018083116108bd57829003601f168201915b505050505090806003018054600181600116156101000203166002900480601f0160208091040260200160405190810160405280929190818152602001828054600181600116156101000203166002900480156109785780601f1061094d57610100808354040283529160200191610978565b820191906000526020600020905b81548152906001019060200180831161095b57829003601f168201915b5050505050908060040154908060050160009054906101000a900460ff16905086565b600060038054905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Assign loyalty contract with web3 using the contract's ABI.
LoyaltyContract = web3.eth.contract(LoyaltyABI)
Next, deploy the contract using the contract byte code.
deployedContract = LoyaltyContract.new([], { data: LoyaltyByteCode })
You can get the contract address by using the transaction hash of the deployed contract.
web3.eth.getTransactionReceipt(deployedContract.transactionHash)
>web3.eth.getTransactionReceipt(deployedContract.)
This contract address will be used to interact with your contract through the application.
In a new terminal window, then provide environment variables for the second proxy using this config file, a new port number, and the different org:
export FABPROXY_CONFIG=${GOPATH}/src/github.com/hyperledger/fabric-chaincode-evm/examples/first-network-sdk-config.yaml # Path to a compatible Fabric SDK Go config file
export FABPROXY_USER=User1 # User identity being used for the proxy (Matches the users names in the crypto-config directory specified in the config)
export FABPROXY_ORG=Org2 # Organization of the specified user
export FABPROXY_CHANNEL=mychannel # Channel to be used for the transactions
export FABPROXY_CCID=evmcc # ID of the EVM Chaincode deployed in your fabric network
export PORT=5001 # Port the proxy will listen on.
Navigate to the fabric-chaincode-evm cloned repo:
cd $GOPATH/src/github.com/hyperledger/fabric-chaincode-evm/
You can then run the second Fab3:
./fab3
This will start Fab3 at http://localhost:5001
This second Fab3 will allow the user from Org2 to register as member on the the loyalty points network.
Now we can run the web application in this repo to interact with the deployed smart contract.
-
First, clone the repo:
git clone https://github.com/IBM/loyalty-points-evm-fabric.git -
Build the application by navigating to
web-appfolder from the root directory and building the the node dependancies:cd web-app npm install -
Update the contract address for the application in the dapp.js file
-
Update the provider for the application in the dapp.js file to use the proxy for the partner i.e
http://localhost:5000 -
Start the application
npm startThe application will be hosted at: http://localhost:8000/
-
Register the account as Partner
-
Access the app as Partner
-
Update the provider for the application in the dapp.js file to use the proxy for the member i.e
http://localhost:5001 -
Start the application
npm startThe application will be hosted at: http://localhost:8000/
-
Register the account as Member
-
Access the app as Member. Once inside the portal you can perform transactions to earn or redeem points from the partners on the network, and view all transactions.
- Solidity contract with Truffle
- Using remix to get ABI and bytecode
- Setup Fab Proxy and using Web3
- Loyalty Program Use Case
This application demonstrates a basic idea of loyalty points using Blockchain and can be expanded in several ways:
- Updating the solidity contract with a constructor to initialize the user deploying the contract as the main Partner for the program, while subsequent Partners would request permission from the main Partner to join the network
- Updating the solidity contract and the application with deals and inventory of the products, where a Partner can update these deals and inventory. The inventory of the products would get updated upon each transaction
- Adding events to the solidity contract transaction which are captured by the application and stored in an off-chain storage and accessed by the application