Connect to a network using Truffle

You can connect to a Quorum Blockchain Service (QBS) network using Truffle, which allows you to deploy smart contracts to QBS.

This guide uses the Truffle command line interface for interacting with QBS.

You can also connect to a network using Visual Studio Code with Truffle.

Prerequisites

Install MetaMask.
Install Truffle.
Install and configure Node.js.
Get your QBS connection string.

Steps

Initialize Truffle on your project folder:
```
truffle init
```
Install Truffle's HDWalletProvider:
```
npm install @truffle/hdwallet-provider
```

Set environment variables with dotenv.

Install dotenv:

npm install --save dotenv

Create a .env file in your project's root folder, and set environment variables in the file as follows:

MNEMONIC = // (string) your MetaMask 12-word seed phrase
RPC_URL = // (string) your QBS connection string, e.g. "https://<Node-Name>.<Member-Name>.<Consortium-Name>.onquorum.net:3200/<API-Key>"

!!! critical "Security warning"

**Keep your mnemonic secret.**

Mnemonics must be kept secret and not committed to any code respositories.
Improper handling of mnemonics can lead to loss of funds and identity fraud.

Edit truffle-config.js with the following text:

const HDWalletProvider = require("@truffle/hdwallet-provider");
const fs = require("fs");
require("dotenv").config(); // store environment variables from '.env' to process.env

module.exports = {
  // See <http://truffleframework.com/docs/advanced/configuration>
  // to customize your Truffle configuration
  networks: {
    default: {
      host: "127.0.0.1", // Localhost (default: none)
      port: 8545, // Standard Ethereum port (default: none)
      network_id: "*", // Any network (default: none)
    },

    qbs: {
      // Provider has to be wrapped into a function
      provider: () =>
        new HDWalletProvider(process.env.MNEMONIC, process.env.RPC_URL),
      network_id: "*", // Any network (default: none)
      gasPrice: 0,
      gas: 4500000,
      type: "quorum",
    },
  },
  compilers: {
    solc: {
      version: "0.7.0",
    },
  },
};

Deploy to QBS:
```
truffle migrate --network qbs
```

Connect to a network using Truffle

Prerequisites​

Steps​

Prerequisites

Steps