What is use of HDWalletProvider in Truffle config?

Question

The sample code here for deploying to Ropsten used HDWalletProvider and a mnemonic in the configuration, but I am not sure I understand its purpose.

Is this just telling it the account that will become the contract owner when you deploy?

var HDWalletProvider = require("truffle-hdwallet-provider");

// 12-word mnemonic
var mnemonic = process.env.NMEMONIC;

module.exports = {
  networks: {
    development: {
      host: "127.0.0.1",
      port: 8545,
      network_id: "*" // Match any network id
    },
    ropsten: {
      provider: new HDWalletProvider(mnemonic, "https://ropsten.infura.io/"),
      network_id: 3 // official id of the ropsten network
    }
  }
};

Answer 1

The Truffle HDWallet provider is a convenient and easy to configure network connection to ethereum through infura.io (or any other compatible provider).

For example the HDWallet provider add some features required by Truffle that are not available with infura like event filtering and transaction signing.

Answer 2

When deploying a contract you eventually need to sign a transaction with an account (with a private key).

This account management process is handled by the provider, in this case, the @truffle/hdwallet-provider (Note that truffle-hdwallet-provider is deprecated). This could be another provider like Metamask or a local Web3 provider.

Answer 3

HDWallet provider is used by truffle when we deploy the contract however metamask providers are used when we want to interact with the contract in the browser.