Smart Contract Migration

Smart Contract Dependency Diagram

The following diagram shows the dependency between smart contracts. MicroToken smart contract implements the ERC20 Token Interface(IERC20). UserIdentity smart contract stores the stake holders’ details. BankLoan, InsurancePolicy, LoanPayment smart contracts uses UserIdentity smart contract to verify the users.

Migration

User Identity and Other Smart Contract Migration

We use following code to deploy UserIdentity and other smart contracts.

const UserIdentity = artifacts.require("UserIdentity");
const BankLoan = artifacts.require("BankLoan");
const InsurancePolicy = artifacts.require("InsurancePolicy");

module.exports = async function(deployer, network, accounts)
{
    await deployer.deploy(UserIdentity);
    const userIdentityInstance = await UserIdentity.deployed();

    await deployer.deploy(BankLoan, userIdentityInstance.address);
    await deployer.deploy(InsurancePolicy, userIdentityInstance.address, {from: accounts[1]});
};

Filename: migrations/3_user_identity_migration.js

As describe in above migration, first we insert all the contracts we’d like to interact with (UserIdentity, BankLoan, InsurancePolicy). As shown in the above Smart Contract Dependency Diagram BankLoan and InsurancePolicy smart contracts need UserIdentity smart contract address to deploy. To achieve this first we deploy the UserIdentity smart contract. We use async/await methods to deploy these contracts. After deploying the UserIdentity smart contract we wait for it finishes the deployment. Then we deploy other 2 smart contract with UserIdentity smart contract address as a parameter.

Bank is the owner of UserIdentity and BankLoan smart contracts. But for the InsurancePolicy smart contract Insurance Company is the owner. To fullfill this requirement we deploy InsurancePolicy smart contract with a different account. We can define optional parameters as the third argument for the deployer.deploy function. We specify the second account of the accounts array as the dployer account for the InsurancePolicy smart contract. If not specify the deployer account it will take the first account as the deployer account.