truffle-config.js

require('dotenv').config()
const HDWalletProvider = require('@truffle/hdwallet-provider');

module.exports = {
  /**
   * Networks define how you connect to your ethereum client and let you set the
   * defaults web3 uses to send transactions. If you don't specify one truffle
   * will spin up a development blockchain for you on port 9545 when you
   * run `develop` or `test`. You can ask a truffle command to use a specific
   * network from the command line, e.g
   *
   * $ truffle test --network <network-name>
   */

  networks: {
    // Useful for testing. The `development` name is special - truffle uses it by default
    // if it's defined here and no other network is specified at the command line.
    // You should run a client (like ganache-cli, geth or parity) in a separate terminal
    // tab if you use this network and you must also set the `host`, `port` and `network_id`
    // options below to some value.
    //
    development: {
      host: "127.0.0.1",     // Localhost (default: none)
      port: 9545,            // Truffle Develop port
      network_id: "*"       // Any network (default: none)
     },
    // Another network with more advanced options...
    // advanced: {
    // port: 8777,             // Custom port
    // network_id: 1342,       // Custom network
    // gas: 8500000,           // Gas sent with each transaction (default: ~6700000)
    // gasPrice: 20000000000,  // 20 gwei (in wei) (default: 100 gwei)
    // from: <address>,        // Account to send txs from (default: accounts[0])
    // websockets: true        // Enable EventEmitter interface for web3 (default: false)
    // },
    // Useful for deploying to a public network.
    // NB: It's important to wrap the provider as a function.
    ropsten: {
       provider: () => new HDWalletProvider(process.env.PRIV_KEY, process.env.INFURA_IDKEY),
       network_id: 3,       // Ropsten's id
       gas: 5500000,        // Ropsten has a lower block limit than mainnet
    // confirmations: 2,    // # of confs to wait between deployments. (default: 0)
    // timeoutBlocks: 200,  // # of blocks before a deployment times out  (minimum/default: 50)
    // skipDryRun: true     // Skip dry run before migrations? (default: false for public nets )
     },
    // Useful for private networks
    // private: {
    // provider: () => new HDWalletProvider(mnemonic, `https://network.io`),
    // network_id: 2111,   // This network is yours, in the cloud.
    // production: true    // Treats this network as if it was a public net. (default: false)
    // }
  },

  // Set default mocha options here, use special reporters etc.
  mocha: {
    // timeout: 100000
  },

  // Configure your compilers
  compilers: {
    solc: {
       version: "0.7.0",    // Fetch exact version from solc-bin (default: truffle's version)
      // docker: true,        // Use "0.5.1" you've installed locally with docker (default: false)
      // settings: {          // See the solidity docs for advice about optimization and evmVersion
       optimizer: {
          enabled: true,
          runs: 200
        },
      //  evmVersion: "byzantium"
      // }
    }
  }
};