Prerequisites

After completing these set up steps, we’ll be ready to start developing with the UMA system locally.

The following steps require the git CLI to be installed. If you are on Windows, you can install via Git Bash Shell (link).

Core

Clone the UMA repo. Start in the top-level directory in this repository, protocol/.

  1. Install the latest stable version of nodejs and ensure that npm is installed along with it.

  2. Run npm install in protocol/.

We should be able to compile the smart contracts from protocol/core:

cd core
$(npm bin)/truffle compile

If everything worked, we should see the line "> Compiled successfully using:" in the output.

Ganache

  1. Install the Ganache UI.

  2. Run Ganache on localhost port 9545 (use the above links for instructions on how to do this).

  3. Under "Accounts & Keys", set the "Account Default Balance" to 1000000. This will ensure that you have enough local testnet ETH to run through tutorials.

  4. Note that to deploy new ExpiringMultiPartyCreator, the main factory used in the priceless financial contract, you must set your gas limit to at least 9 million in Ganache. To do this, under "Chain", set the "Gas Limit" field 10 million (10000000). This will enable your Ganache instance to deploy larger contracts.

You can also run the Ganache from the command line with identical settings as follows:

ganache-cli -p 9545 -e 1000000 -l 10000000

If everything was setup correctly, we should be able to run automated tests from protocol/core:

cd core
$(npm bin)/truffle test --network test

These tests will take a while to finish, but if set up correctly, all tests should pass.

Keys and Networks

When using UMA infrastructure, you often have to open the truffle console or run a script using truffle exec. When using truffle in the context of this repository, it’s important to understand what types of keys you can use and what to specify for the --network argument.

Public Networks

Public networks include the Ethereum mainnet and any public testnets, like Rinkeby, Kovan, or Ropsten. If you are using these networks, you’ll generally need to know:

  1. Which public network you intend to use. A list of UMA supported networks is available here.

  2. What private key you want to use and how your private keys are stored. Below is information regarding the two types of keys that are supported, mnemonics/seed phrases and hardware wallets.

The --network parameter that’s passed to all truffle commands depends on both of these factors. Here’s an example:

$(npm bin)/truffle console --network rinkeby_mnemonic

That command will tell truffle that the user wants to use the Rinkeby testnet and their private key is a mnemonic, or seed phrase. Generally, the network argument is structured as --network [NETWORK_NAME]_[KEY_TYPE].

Mnemonic, or seed phrase (less secure)

Mnemonics are much less secure than using a hardware wallet, but they are also much faster when sending multiple transactions since they don’t require as much user input. If you’d like to use a mnemonic, you’ll need to start by putting the mnemonic in your shell environment. Do this by running the following command:

export MNEMONIC="YOUR_MNEMONIC_HERE"

With a real mnemonic, this would look like:

export MNEMONIC="candy maple cake sugar pudding cream honey rich smooth crumble sweet treat"

Once you’ve done that you’re ready to run a truffle command. When using a mnemonic, your network argument should look be --network [NETWORK_NAME]_mnemonic. So, for example, using a mnemonic on kovan would look like:

$(npm bin)/truffle console --network kovan_mnemonic

Hardware wallets (more secure)

Hardware wallets are the more secure way to interact with the system on public networks. We currently only support Ledger hardware wallets, but we plan on supporting more in the future.

To set up a Ledger hardware wallet for use with our system:

  1. Connect the device to your machine.

  2. Use your passcode to unlock it.

  3. Ensure the Ethereum app is installed on your device. Install it if not.

  4. Select the Ethereum app on the device.

  5. Go to the Ethereum app settings on the device and change the "Contract data" setting to yes if it isn’t already.

Now that you’re set up, you should be able to run truffle commands with the network argument --network [NETWORK_NAME]_ledger. Note: this network uses the default Ledger Live derivation path: m/44'/60'/x'/0/0. For the legacy derivation path (m/44'/60'/0'/x), use [NETWORK_NAME]_legder_legacy.

For example, you could connect your ledger wallet to the truffle console and begin running commands against mainnet with the following command:

$(npm bin)/truffle console --network mainnet_ledger

Note: outgoing transactions will require manual approval on the ledger device. If you fail to approve, the command will hang.

© UMA Project 2018-2019