Creating tokens locally

In this tutorial, we’ll create a BTC/USD token collateralized with an ERC-20 token (a stand in for DAI) via the UMA token builder. We will spin up the system locally on Ganache, push a price for BTC/USD, and create a token.

Prerequisites

All of our tutorials require that you complete the steps in Prerequisites.

Deploy smart contracts to Ganache

First, we’ll start a blockchain locally using Ganache and deploy the UMA smart contracts to it. The underlying products we can track are configured via a json file identifiers.json. More details on this can be found here.

Run all commands in this section from the core/ directory.

  1. Start the Ganache UI.

  2. Deploy smart contracts to the locally running Ganache instance via:

$(npm bin)/truffle migrate --reset --network test

After this step, the smart contracts are deployed and can be interacted with.

Pushing prices (manually)

Run all commands in this section from the core/ directory.

In production, we can run a job on a cloud provider that fetches prices from a data API and pushes them to the blockchain. An example of such a script is core/scripts/PublishPrices.js.

Locally, however, let’s skip the step of setting up a data feed and manually push a price for BTCUSD via:

$(npm bin)/truffle exec scripts/ManualPublishPriceFeed.js --identifier BTC/USD --price <price> --time <time> --network test

where <price> is the current price of Bitcoin in USD and <time> is the current UNIX timestamp in seconds.

For example, if the price of Bitcoin were $8,923 at 10/21/2019 15:40 EDT, run:

$(npm bin)/truffle exec scripts/ManualPublishPriceFeed.js --identifier BTC/USD --price 8293 --time 1571686800 --network test

UMA token builder

Run all commands in this section from the sponsor-dapp-v2/ directory.

  1. Run npm start to start the UMA token builder GUI.

  2. Chrome should automatically load the UI. If not, navigate to localhost:3000.

  3. Click on "Get Started".

  4. Click on "Testnet DAI faucet" to get some of the ERC-20 token we’ll be using as collateral.

  5. Click "Open token facility" and select "BTC/USD" as the price index. Go through the remaining set up flow.

We now have a synthetic token tracking the BTC/USD price.

To see our token valuation change as the BTC price changes, we can either push more prices using ManualPublishPriceFeed.js, as above, or see the price-feed-configuration.md doc to set up a real price feed.

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