Supply Chain Decentralized Application

Blockchain is a platform that contains blocks of data about transactions between parties. The data structure within blockchain links these blocks of data to create a ledger of all the transactions. The data is cryptographically authenticated to prevent alteration and spread of any corrupt entry. Blockchain has several participant nodes that have full or partial copies of the blockchain. The participant nodes act as validators and consumers of the blockchain. A consensus algorithm allows all the participating nodes in the blockchain to agree on what data needs to be added to the ledger and verified as accurate.

One use case of blockchain is to track different types of transactions in a supply chain in a secure and transparent manner. Starting from the manufacturer to the sale of the product every transaction in the supply chain is documented to reduce costs and minimize human error. The supply chain decentralized application (dApp) uses smart contracts, which are self-executing contractual promises, stored on the blockchain that no one controls, and everyone can trust. The supply chain dApp can be used on VMware Blockchain or other Ethereum-based blockchain.

Quick Setup with Docker

Install docker here

First lets clone and build the container.

git clone [email protected]:vmware-samples/vmware-blockchain-samples.git

docker-compose build

Update the truffle-config.js with the correct url, username and password.

  vmware: {
    network_id: "*",
    provider: () => new Web3.providers.HttpProvider(
      "https://<username>:<password>@<url>"
    )
  },

Deploy contracts by running truffle migrate by using our container.

docker-compose run supply-chain truffle migrate --network=vmware  

Update the environment BC_URL endpoint in the docker-compose.yml file to point at your ETH RPC instance.

    volumes:
      - ./contracts:/app/contracts
      - ./migrations:/app/migrations
      - ./build:/app/build
      - ./truffle-config.js:/app/truffle-config.js
    environment:
      # Example
      # - BC_URL=http://localhost/blockchains/local/api/concord/eth
      - BC_URL=<change-me>

Then start the server and go to localhost:4200 once its built.

docker-compose up

Configure and Deploy Without Docker

Prerequisites

• Verify that you have Git, Docker, Node 8.9+ and npm installed.
• Verify that you have installed and configured Truffle v4 suite framework for smart contracts in your environment. See the Truffle suite installation.

npm install -g [email protected]

• Verify that the Ganache application, an Ethereum network simulator is running properly. See Ganache installation.

Setup

Install application dependencies

npm install

Deploy contracts on ganache

truffle migrate --reset --network=development 

Deploy contracts on VMware blockchain

First go to truffle-config.js and update the username, password and path under the vmwware network:

    vmware: {
      network_id: "*",
      provider: () => new Web3.providers.HttpProvider(
        "http://<username>:<password>@vmware.blockchain/blockchains/change/api/concord/eth/"
      )
    },

Then deploy the contracts

truffle migrate --reset --network=vmware 

Run tests to verify everything is working correctly

# On ganache
npm run truffle:test:ganache

# On vmware blockchain
npm run truffle:test:vmware

Now lets interact with the contracts, by using the truffle console.

truffle console

In the console

# Get the deployed contract
let contract;
Orders.deployed().then(function(c){ contract = c});

# Create an order
contract.create(web3.fromAscii("Apples"), 100);

# Get the order address you just created
contract.orders.call(0)
'0xf0de5c223985434b12b8c858ccfa9b9a309a0251'

# Initialize the order into our ABI
# Application Binary Interface (ABI) is a list of the contract's functions and arguments in the JSON format. To use a smart contract's function the ABI is used to hash the function definition so it can create the EVM bytecode required to call the function.
let order = Order.at('0xf0de5c223985434b12b8c858ccfa9b9a309a0251');

# Assign owners
order.setOwners.sendTransaction('0xfa1a4c33aa682d34eda15bf772f672edddac13aa', '0xfa1a4c33aa682d34eda15bf772f672edddac13aa', '0xfa1a4c33aa682d34eda15bf772f672edddac13aa', '0xfa1a4c33aa682d34eda15bf772f672edddac13aa', '0xfa1a4c33aa682d34eda15bf772f672edddac13aa');
'0x221030d0af4734a7e8c8dade5cdd945e9940efa35725daaee3315ff908dd108b'

# Approve the order
order.approve.sendTransaction();
'0xdef210546df026c422f7e1c01785abbf147ec2ae95a7d2a96bf8b8e6edfa345e'

# Get metadata
order.meta.call();
[ '0x4170706c65730000000000000000000000000000000000000000000000000000',
  BigNumber { s: 1, e: 2, c: [ 100 ] },
  false ]

# Make the metadata more readable
 web3.toAscii('0x4170706c65730000000000000000000000000000000000000000000000000000');
'Apples\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000'

# Additional metadata improvements
web3.toUtf8('0x4170706c65730000000000000000000000000000000000000000000000000000');
'Apples'

Startup Dev Server

Ganache

npm run start:ganache

VMware Blockchain

Update the proxy.conf.json file with the correct target path to your vmware blockchain instance.

npm run start:vmware

Code scaffolding

Run ng generate component component-name to generate a new component. You can also use ng generate directive|pipe|service|class|guard|interface|enum|module.

Running unit tests

Run npm run test to execute the unit tests via Karma.

Style Guide and Overall Structure

Use the angular cli generate commands and this styleguide for style guidance.

Further help

To get more help on the Angular CLI use ng help or go check out the Angular CLI README.