Using Truffle with Geth Instead of Ganache

So, as a real blockchain developer, you will sooner or later want to test your smart contract in an environment that closely resembles a real blockchain. Ganache, an in-memory blockchain emulator, only takes you so far. In this case, you're going to use Go Ethereum (Geth) and most likely Truffle for writing, testing, and deploying your contracts.

Using Ganache + Truffle is easy. They feel like they were made for each other. But pairing Truffle + Geth often brings issues. In this post, I'll walk you through solving the problems I encountered.

Environment Setup

Item	Value
Go Ethereum (geth)	`1.10.19-stable` (ARM64 build)
Truffle	`5.5.18`
Goal	Deploy smart contracts through Truffle to Geth and be able to interact with them.

Geth Command

geth --networkid 4224 --mine --miner.threads 1 --datadir "./private" --nodiscover -port "30303" --nat "any" \
  --http --http.api personal,eth,net,web3 \
  --ws --ws.api personal,eth,net,web3 \
  --password ./private/password.sec --ipcpath "~/Library/Ethereum/geth.ipc"

Notice the --password flag. It points to a password file for unlocking the account securely.

Truffle Configuration (`truffle-config.js`)

geth: {
  host: "127.0.0.1",
  port: 8545,
  network_id: 4224,
  from: '0x6db7f74b66403832fc2cfa40d6ee79f1b6915e37',
}

Create this account using:

geth --datadir . account new

You can skip the password prompt or use a file.

The Problem

Running:

truffle migrate --network geth

Results in an authentication error.

Solution: unlock the account

Add --allow-insecure-unlock to your Geth command:

geth ... --allow-insecure-unlock

Modify the Truffle migration script

Update migrations/1_initial_migration.js:

const Migrations = artifacts.require('Migrations');
const TruffleConfig = require('../truffle-config');
const Web3 = require('web3');

module.exports = function (deployer, network, accounts) {
  const config = TruffleConfig.networks[network];
  if (process.env.ACCOUNT_PASSWORD) {
    const web3 = new Web3(new Web3.providers.HttpProvider(`http://\${config.host}:\${config.port}`));
    web3.eth.personal.getAccounts().then((accounts) => {
      const defaultAccount = accounts[0];
      console.log(`[x] Unlocking account \${defaultAccount}`);
      web3.eth.personal.unlockAccount(defaultAccount, process.env.ACCOUNT_PASSWORD);
    });
  }
  console.log('[x] Making migrations');
  deployer.deploy(Migrations);
};

Option 2: unlock in Geth console

Start Geth
In another terminal:

geth attach

Then:

personal.unlockAccount('0x6db7f74b66403832fc2cfa40d6ee79f1b6915e37', 'your_password');

Re-run the migration:

truffle migrate --network geth

You're good to go!

Table of Contents

Using Truffle with Geth Instead of Ganache
Environment Setup
Geth Command
Truffle Configuration (truffle-config.js)
The Problem
Solution: unlock the account
Modify the Truffle migration script
Option 2: unlock in Geth console

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