Price Feeder
The price-feeder tool is an extension of UX'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 Fiat or USD Stablecoins e.g. USDC
- No need or use of reference exchange rates (e.g. Luna).
- No need or use of Tobin tax.
- The
price-feedercombines bothfeederandprice-serverinto a single Golang-based application for better UX, testability, and integration.
Background
The price-feeder tool is responsible for performing the following:
- Fetching and aggregating exchange rate price data from various providers, e.g. Binance and Osmosis, based on the operator configuration. These exchange rates are exposed via API and are used to feed up to the minute pricing into the main oracle process.
- Aggregating exchange rate price data and submitting those exchange rates on-chain to UX's
x/oraclemodule following the UX's Oracle specification.
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. The keyring's password is defined via environment variables or user input. More information on the keyring can be found here Please see the example configuration for more details.
$ price-feeder /path/to/price_feeder_config.toml
Setup
The keyring dir and backend are defined in the config file. You may use the PRICE_FEEDER_PASS environment variable to set up the keyring password.
Ex : export PRICE_FEEDER_PASS=keyringPassword
If this environment variable is not set, the price feeder will prompt the user for input.
Configuration
server
The server section contains configuration pertaining to the API served by the price-feeder process such as the listening address and various HTTP timeouts.
currency_pairs
The currency_pairs sections contain one or more exchange rates along with the providers from which to get market data. 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",
"ftx",
"okx",
]
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 time-weighted average price (TVWAP).
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 on-chain data that pertain to oracle functionality and for broadcasting signed pre-vote and vote oracle messages.
Keyring
The UX keyring must be set up to sign transactions before running the price feeder. Additional info on the different keyring modes is available here. Please note that the test and memory modes are only for testing purposes. Do not use these modes for running the price feeder against the mainnet.
Providers
The current list of supported providers:
