Is there a way to read hardhat config inside a script at runtime and console.log certain attributes?

Question

I want to add some nice output in my hardhat scripts for showing what my configurations are during a test run. I run the script locally while changing configuration variables and I want the console output to reflect those config changes so that I can more easily track things.

For example, here is my hardhat.config.js:

require("@nomiclabs/hardhat-waffle");
require("dotenv").config();

/**
 * @type import('hardhat/config').HardhatUserConfig
 */
module.exports = {
  solidity: "0.8.4",
  networks: {
    rinkeby: {
      url: process.env.ALCHEMY_URL,
      // url: process.env.INFURA_URL,
      // url: process.env.QUICKNODE_URL,
      // url: process.env.MORALIS_URL,
      accounts: [process.env.PK]
    }  
  }
};

And here is my workflow:

1. run the script with existing settings

thatguyintech@albert eth-call-analysis % npx hardhat run scripts/sample-script.js
rpc url: localhost
GasLimits contract deployed to: 0x5FbDB2315678afecb367f032d93F642f64180aa3

2. change the url config and re-run

thatguyintech@albert eth-call-analysis % npx hardhat run scripts/sample-script.js --network rinkeby
rpc url:  https://eth-rinkeby.alchemyapi.io/v2/<my api key>
GasLimits contract deployed to: 0xeb8aeddb118b8141ea4e0e0e0d7e7ee685f214ac

In order to get the above output, my sample-script.js looks like this:

const hre = require("hardhat");

async function main() {
  console.log("rpc url: ", process.env.ALCHEMY_URL) // I have to manually change this on each run.

  // We get the contract to deploy
  const GasLimits = await hre.ethers.getContractFactory("GasLimits");
  const gasLimits = await GasLimits.deploy();

  await gasLimits.deployed();

  console.log("GasLimits contract deployed to:", gasLimits.address);
}

Is there a way to read the hardhat.config.js values at runtime so that I don't have to rely on dotenv and change my script manually on each run?

Specifically, is there a way to rewrite console.log("rpc url: ", process.env.ALCHEMY_URL) into something that can automatically update based on how I've set my hardhat.config.js? Maybe something like this: console.log("rpc url: ", hre.config.networks.url)?

---

Update: I do see in the hardhat runtime environment docs that there is an hre.config object I can use. However, I don't want to know about the original configuration, I want to know the network that is currently be used at runtime at the time that my script is invoked. Any tips for that?

Answer 1

Great question; try something like this:

Use hre.network.config.url;

Here is an example of how you can get the RPC Provider URL at runtime in your deploy.js script:

const hre = require("hardhat");

console.log("provider url: ", hre.network.config.url);

So then, for example if you run the deploy locally, the provider URL might be undefined:

% npx hardhat run scripts/deploy.js
provider url:  undefined

But if you switch to a network that you have defined, you will then see the api provider URL:

% npx hardhat run scripts/deploy.js --network rinkeby
provider url:  https://eth-rinkeby.alchemyapi.io/v2/<api-key>

Answer 2

If I understand correctly what you are trying to get in the updated part of the question, I think you can use hre.network.name, which is the name of the current network set in the config file that the hre is currently running with.

Basically, if you want to access the raw config values, use hre.config, if you want to know which network the hre is currently running with, use hre.network.name

Answer 3

The hre contains the default RPC at hre.ethers.provider.connection.url which will return something like http://localhost:8545.

Answer 4

This is how I did it in my testcase:

const hardhatConfig = require("../hardhat.config"); console.log(hardhatConfig.networks.hardhat.forking.url)