price-feeder

README

Oracle Price Feeder

The price-feeder tool is an extension of Umee's x/oracle module, both of which are based on Terra's x/oracle module and oracle-feeder. The core differences are as follows:

• All exchange rates must be quoted in USD or USD stablecoins.
• No need or use of reference exchange rates (e.g. Luna).
• No need or use of ToBin tax.
• The price-feeder combines both feeder and price-server into a single Golang-based application for better UX, testability and integration.

Background

The price-feeder tool is responsible for performing the following:

1. Fetching and aggregating exchange rate price data from various providers, e.g. Binance and Osmosis, based on operator configuration. These exchange rates are exposed via an API and are used to feed into the main oracle process.
2. Taking aggregated exchange rate price data and submitting those exchange rates on-chain to Umee's x/oracle module following Terra's Oracle specification.

Providers

The list of current supported providers:

• Binance
• Huobi
• Kraken
• Osmosis

Usage

The price-feeder tool runs off of a single configuration file. This configuration file defines what exchange rates to fetch and what providers to get them from. In addition, it defines the oracle's keyring and feeder account information. Please see the example configuration for more details.

$ price-feeder /path/to/price_feeder_config.toml

Configuration

server

The server section contains configuration pertaining to the API served by the price-feeder process such the listening address and various HTTP timeouts.

currency_pairs

The currency_pairs sections contains one or more exchange rates along with the providers from which to get market data from. It is important to note that the providers supplied in each currency_pairs must support the given exchange rate.

For example, to get multiple price points on ATOM, you could define currency_pairs as follows:

[[currency_pairs]]
base = "ATOM"
providers = [
  "binance",
]
quote = "USDT"

[[currency_pairs]]
base = "ATOM"
providers = [
  "kraken",
  "osmosis",
]
quote = "USD"

Providing multiple providers is beneficial in case any provider fails to return market data. Prices per exchange rate are submitted on-chain via pre-vote and vote messages using a volume-weighted average price (VWAP).

account

The account section contains the oracle's feeder and validator account information. These are used to sign and populate data in pre-vote and vote oracle messages.

keyring

The keyring section contains Keyring related material used to fetch the key pair associated with the oracle account that signs pre-vote and vote oracle messages.

rpc

The rpc section contains the Tendermint and Cosmos application gRPC endpoints. These endpoints are used to query for on-chain data that pertain to oracle functionality and for broadcasting signed pre-vote and vote oracle messages.