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Truffle Migrate

This project is an example that shows how to create a new project from scratch that depends on DutchX and how you can deploy the DutchX contracts in a ganache-cli local node.

It shows how to deploy easily the contracts in a local ganache-cli, so we don't depend on testnets like Rinkeby and we can speed up the development.

Also, using truffle brings many other advantages like test, migrations, easier interaction, sharing compiled contracts into NPM packages, etc...

For more info on truffle see:

This example is part of the guide

You can find other examples in the Build on top of DutchX project

Have you done the first example?

Maybe you should consider doing the basic web example first.

That example doesn't use truffle, and it shows the basics on how to integrate with DutchX.

Create a basic truffle contract

Create your my-cool-app project:

mkdir my-cool-app
cd my-cool-app
npm init

Make it a Truffle 5 project:

mkdir contracts migrations
npm install --save-dev truffle@^5.0.0-beta.2 truffle-hdwallet-provider@^1.0.0-web3one.1 truffle-contract

If you prefer to stick to Truffle 4 for now, you can, you can alter slight the steps to adapt it to this version.

It just change thes small changes from the original guide:

  • Dependencies: npm install --save-dev truffle truffle-hdwallet-provider truffle-contract
  • truffle.js: When configuring the project, use this truffle4.js as your truffle config.
  • DutchX migration script: Use the ones in the dir [migrations-truffle-4](./migrations-truffle-4)
  • Example contracts: Use the ones in the dir [contracts-truffle-4](./contracts-truffle-4)

Add a truffle config

Add truffle.js into the root of the project.

This truffle config file, has a pretty standard boilerplate config with:

  • Networks: Define networks: ganache-cli (development), rinkeby, kovan and mainnet.
  • Mnemonic: Configured with a default test mnemonic. It allows to change it by providing the MNEMONIC environment variable.
    • Default Mnemonic: candy maple cake sugar pudding cream honey rich smooth crumble sweet treat
    • Default address: 0x627306090abab3a6e1400e9345bc60c78a8bef57
    • IMPORTANT: Don't use this mnemonic for mainnet with real funds. This is a public test mnemonic used in many projects.
  • Gas price: Configured with a default gas price. It allows to change it by providing the GAS_PRICE_GWEI environment variable.
    • Default Gas Price: 5 Gwei
  • It prints useful information

Add the first migration and it's contract

Just copy the Migrations contract and it's migration (this is pretty common on all truffle projects):

Add DutchX as a NPM dependency

npm install --save-dev

Make sure truffle finds the dependencies

Copy the code from:

With this new contract, we ensure that for local development, truffle finds all DutchX contract.

This contract won't do anything, it won't event have code, the important thing is that it must import so truffle will pull and compile all the required contracts.

For more information, check:

Compile DutchX contracts

Compile the contracts.

npx truffle compile

We'll see how the DutchExchange is being compiled among all the other contracts it depends on:

We should see something very similar to:

Compiling contracts

Migrate the DutchX to local-ganache

Copy this file into your project:

This truffle migration:

  • Only executes in the development network (Note that rinkeby and mainet contracts are already deployed).
  • Uses the contracts that are in our NPM dependencies, so we avoid repetition.
  • Uses the migration scripts that are in our NPM dependencies. DutchX NPM module provides a simple migration source that can be referenced to ease the local development.

For more information, check:

Apply the migrations

# Run a ganache cli
npx ganache-cli -d

# Run migrations
#   It's also a good idea to add it a a package.json script
npx truffle migrate

Truffle will migrate automatically all contracts:

Migrating contracts

Truffle console

If we execute npx truffle networks at this point, we can verify the addresses of the contracts deployed to the local ganache-cli.

Deployed contracts

If we run npx truffle console, we'll be able to play arround with the deployed DutchX smart contracts.

npx truffle console

# Truffle 5 (web3 1.0)
truffle(development)> dutchx = await
truffle(development)> => n.toString())

# Truffle 4 (web3 0.20)
truffle(development)> dutchx =
truffle(development)> => n.toNumber())

Truffle console

Next steps

Congratulations! you now have a truffle project that deploys all the DutchX contracts as part of it's first migration.

Now you can continue with Example 03: Onchain integration - Use it as an oracle:

  • This example shows how to create your own contract and migrations that makes use of the DutchX.
  • In this example we will create a Safe contract to deposit fund. We will use the DutchX to help us estimate the price in USD for any token in our Safe.