# Truffle Set up a Truffle Ethermint local development environment. {synopsis} ## Pre-requisite Readings - [Installation](./../quickstart/installation.md) {prereq} - [Run a node](./../quickstart/run_node.md) {prereq} [Truffle](https://www.trufflesuite.com/truffle) is a development framework for deploying and managing [Solidity](https://github.com/ethereum/solidity) smart contracts. In this guide, we will learn how to deploy a contract to a running Ethermint network. ## Install dependencies First, install the latest Truffle version on your machine globally. ```bash yarn install truffle -g ``` You will also need to install Ethermint. Check this [document](./../quickstart/installation.md) for the full instructions. ## Create Truffle Project In this step we will create a simple counter contract. Feel free to skip this step if you already have your own compiled contract. Create a new directory to host the contracts and initialize it ```bash mkdir ethermint-truffle cd ethermint-truffle ``` Initialize the Truffle suite with: ```bash truffle init ``` Create `contracts/Counter.sol` containing the following contract: ```javascript pragma solidity ^0.5.11; contract Counter { uint256 counter = 0; function add() public { counter++; } function subtract() public { counter--; } function getCounter() public view returns (uint256) { return counter; } } ``` Compile the contract using the `compile` command: ```bash truffle compile ``` Create `test/counter_test.js` containing the following tests in Javascript using [Mocha](https://mochajs.org/): ```javascript const Counter = artifacts.require("Counter") contract('Counter', accounts => { const from = accounts[0] let counter before(async() => { counter = await Counter.new() }) it('should add', async() => { await counter.add() let count = await counter.getCounter() assert(count == 1, `count was ${count}`) }) }) ``` ## Truffle configuration Open `truffle-config.js` and uncomment the `development` section in `networks`: ```javascript development: { host: "127.0.0.1", // Localhost (default: none) port: 8545, // Standard Ethereum port (default: none) network_id: "*", // Any network (default: none) }, ``` This will allow your contract to connect to your Ethermint local node. ## Start Node and REST server Start your local node using the following command on the Terminal ```bash # on the ~/ethermint/ directory init.sh ``` ::: tip For further information on how to run a node, please refer to [this](./../quickstart/run_node.md) quickstart document. ::: In another Terminal wintdow/tab, start the [REST and JSON-RPC server](./../quickstart/clients.md#rest-and-tendermint-rpc.md): ```bash ethermintcli rest-server --laddr "tcp://localhost:8545" --unlock-key mykey--chain-id 8 --trace ``` ## Deploy contract Back in the Truffle terminal, migrate the contract using ```bash truffle migrate --network development ``` You should see incoming deployment logs in the Ethermint daemon Terminal tab for each transaction (one to deploy `Migrations.sol` and the oether to deploy `Counter.sol`). ```bash I[2020-07-15|17:35:59.934] Added good transaction module=mempool tx=22245B935689918D332F58E82690F02073F0453D54D5944B6D64AAF1F21974E2 res="&{CheckTx:log:\"[]\" gas_wanted:6721975 }" height=3 total=1 I[2020-07-15|17:36:02.065] Executed block module=state height=4 validTxs=1 invalidTxs=0 I[2020-07-15|17:36:02.068] Committed state module=state height=4 txs=1 appHash=76BA85365F10A59FE24ADCA87544191C2D72B9FB5630466C5B71E878F9C0A111 I[2020-07-15|17:36:02.981] Added good transaction module=mempool tx=84516B4588CBB21E6D562A6A295F1F8876076A0CFF2EF1B0EC670AD8D8BB5425 res="&{CheckTx:log:\"[]\" gas_wanted:6721975 }" height=4 total=1 ``` ## Run Truffle tests Now, you can run the Truffle tests using the Ethermint node using the `test` command: ```bash truffle test --network development Using network 'development'. Compiling your contracts... =========================== > Everything is up to date, there is nothing to compile. Contract: Counter ✓ should add (5036ms) 1 passing (10s) ``` ## Next {hide} Learn how to connect Ethermint to [Metamask](./../guides/metamask.md) {hide}