README ¶
Gofer CLI Readme
As in a tool that specializes in the delivery of special items.
Gofer is a tool that provides reliable asset prices taken from various sources.
If you need reliable price information, getting them from a single source is not the best idea. The data source may fail or provide incorrect data. Gofer solves this problem. With Gofer, you can define precise price models that specify exactly, from how many sources you want to pull prices and what conditions they must meet to be considered reliable.
Table of contents
Installation
To install it, you'll first need Go installed on your machine. Then you can use standard Go
command: go install github.com/chronicleprotocol/oracle-suite/cmd/gofer@latest
Alternatively, you can build Gofer using Makefile
directly from the repository. This approach is recommended if you
wish to work on Gofer source.
git clone https://github.com/ma/oracle-suite.git
cd oracle-suite
make
Configuration
Price models configuration
To start working with Gofer, you have to define price models first. Price models are defined in a JSON or YAML file. By
default, the default config file location is gofer.json
in the current directory. You can change the config file
location using the --config
flag.
Simple price model for the BTC/USD
asset pair may look like this:
gofer {
price_model "BTC/USD" "median" {
source "BTC/USD" "origin" { origin = "bitfinex" }
source "BTC/USD" "origin" { origin = "coinbasepro" }
source "BTC/USD" "origin" { origin = "kraken" }
min_sources = 1
}
}
Each price_model
and source
block has two labels. The first label is an asset pair name written as XXX/YYY
,
where XXX
is the base asset name and YYY
is the quote asset name. These symbols are case-insensitive. The second
label defines how the price should be calculated. Currently, the following price calculation methods are supported:
origin
- returns the price from the first source that provides it. It requires one argument,origin
, which is the name of the provider from which the price will be obtained.source "ETH/USD" "origin" { origin = "coinbasepro" }
median
- calculates the median price from sources. It requires at least onesource
block and one optional argument,min_sources
, which is the minimum number of sources that must provide a price for it to be considered reliable.source "ETH/USD" "median" { source "ETH/USD" "origin" { origin = "coinbasepro" } source "ETH/USD" "origin" { origin = "kraken" } min_sources = 2 }
indirect
- calculates the indirect price using two or more asset pairs. It requires at least onesource
block. The price is calculated by determining the cross rate between asset pairs. For example, to calculate the price ofBTC/USD
, the following list of sources can be used:BTC/ETH
,ETH/USD
.source "BTC/USD" "indirect" { source "BTC/ETH" "origin" { origin = "coinbasepro" } source "ETH/USD" "origin" { origin = "coinbasepro" } }
Supported origins:
balancer
- BalancerbalancerV2
- Balancerbinance
- Binancebitfinex
- Bitfinexbitstamp
- Bitstampbithumb
- Bithumbbittrex
- Bittrexcoinbasepro
- CoinbaseProcryptocompare
- CryptoComparecoinmarketcap
- CoinMarketCapddex
- DDEXfolgory
- Folgoryfx
- exchangeratesapi.io (fiat currencies)gateio
- Gateiogemini
- Geminihitbtc
- HitBTChuobi
- Huobikraken
- Krakenkucoin
- KuCoinloopring
- Loopringokex
- OKExopenexchangerates
- OpenExchangeRatespoloniex
- Poloniexsushiswap
- Sushiswapuniswap
- Uniswap V2uniswapV2
- Uniswap V2uniswapV3
- Uniswap V3upbit
- Upbit.
- Special origin that refers to other price models.
Origins configuration
Some origins might require additional configuration parameters, such as an API key. You can define these parameters in the origins section of the config file.
gofer {
origin "openexchangerates" {
type = "openexchangerates"
params = {
api_key = "YOUR_API_KEY"
}
}
}
The block label is the name of the origin. The type parameter defines the origin type. If the label and type are the same, the default origin is replaced.
All origins accept the symbol_aliases
parameter, which is a map of asset symbols to their aliases. This is useful when
the origin uses different symbols than those used in the price model. For example, to treat USDC
as USD
in a price
model, you can use the following configuration under the origin block:
symbol_aliases = {
"USD" = "USDC"
}
Depending on the origin type, different additional parameters can be defined:
-
balancer
,balancerV2
,sushiswap
,curve
,curvefinance
,wsteth
,rocketpool
,uniswap
,uniswapV2
uniswapV3
:contracts
- a map of pairs of asset symbols to their Balancer V2 pool contract addresses. For example:contracts = { "ETH/USD" = "0x58f6b77148BE49BF7898472268ae8f26377d0AA6" }
-
coinmarketcap
,fx
,openexchangerates
:api_key
- API key used to access the origin.
-
curve
,curvefinance
,balancerV2
,wsteth
,rocketpool
:ethereum_client
- Ethereum client used to access the blockchain data.
Additionally, most of the origins accept the url
parameter, which is a URL of the origin API. If not specified,
the default URL will be used.
Hooks
In some cases a check should be done after the median price has been obtained. E.g. in the case of rETH
, a circuit
breaker value is checked against the obtained median, and if the deviation is high enough, a price error will be set.
To define a hook, you can use the hook
block:
gofer {
# ...
hook "RETH/ETH" {
post_price = {
ethereum_client = "default"
circuit_contract = "0xa3105dee5ec73a7003482b1a8968dc88666f3589"
}
}
# ...
}
Configuration reference
This configuration is only a reference and not ready for use. The recommended configuration can be found in
the config.hcl
file located in the root directory.
# List of files to include. The files are included in the order they are specified.
# It supports glob patterns.
include = [
"config/*.hcl"
]
# Custom variables. Accessible in the configuration under the `var` object, e.g. `var.feeds`.
variables {
myvar = "foo"
}
gofer {
# RPC listen address for the Gofer agent. The address must be in the format `host:port`.
# Required only for "gofer agent" command.
rpc_listen_addr = "127.0.0.1:9101"
# RPC agent address for the Gofer agent to connect to. The address must be in the format `host:port`.
# Optional. If empty, Gofer use local price models instead of asking the agent.
rpc_agent_addr = "127.0.0.1:9101"
# Origin configuration. If label and type are the same, the default origin is replaced with the one defined here.
origin "uniswapV3" {
# Base origin type.
type = "uniswapV3"
# List of origin parameters. See the Origins configuration section for more details.
params = {
ethereum_client = "default"
symbol_aliases = {
"BTC" = "WBTC",
"ETH" = "WETH",
"USD" = "USDC"
}
contracts = {
"GNO/WETH" = "0xf56d08221b5942c428acc5de8f78489a97fc5599",
"LINK/WETH" = "0xa6cc3c2531fdaa6ae1a3ca84c2855806728693e8",
"MKR/USDC" = "0xc486ad2764d55c7dc033487d634195d6e4a6917e",
"MKR/WETH" = "0xe8c6c9227491c0a8156a0106a0204d881bb7e531",
"USDC/WETH" = "0x88e6a0c2ddd26feeb64f039a2c41296fcb3f5640",
"YFI/WETH" = "0x04916039b1f59d9745bf6e0a21f191d1e0a84287"
}
}
}
# Price model configuration. First label is the pair name and must be in the format of "BASE/QUOTE". Second label
# specifies how the price is calculated. Details about the price model can be found in the "PPrice models configuration"
# section of this document.
price_model "ETH/USD" "median" {
source "ETH/USD" "indirect" {
source "ETH/BTC" "origin" { origin = "binance" }
source "BTC/USD" "origin" { origin = "coinbasepro" }
}
source "ETH/USD" "origin" { origin = "bitstamp" }
source "ETH/USD" "origin" { origin = "coinbasepro" }
source "ETH/USD" "origin" { origin = "gemini" }
source "ETH/USD" "origin" { origin = "kraken" }
source "ETH/USD" "origin" { origin = "uniswapV3" }
min_sources = 3
}
# Hook configuration.
hook "ETH/USD" {
post_price = {
ethereum_client = "default"
circuit_contract = "0x1234567890123456789012345678901234567890"
}
}
}
# Gofer origins and hooks may require access to Ethereum blockchain. This section defines Ethereum clients
# used by Gofer.
# Optional.
ethereum {
# Configuration for Ethereum clients. The client name is used to reference the client in other sections.
# It is possible to have multiple clients in the configuration.
client "default" {
# RPC URLs is a list of Ethereum RPC URLs to use for the client. Ethereum client uses RPC-Splitter which compares
# responses from multiple RPC URLs to verify that none of them are compromised. At least three URLs are recommended
# in case of using a 3rd party RPC service.
rpc_urls = ["https://eth.public-rpc.com"]
# Chain ID of the Ethereum network.
chain_id = 1
}
}
Environment variables
It is possible to use environment variables anywhere in the configuration file. Environment variables are accessible
in the env
object. For example, to use the HOME
environment variable in the configuration file, use env.HOME
or env("HOME",".")
expression.
Commands
Gofer is designed from the beginning to work with other programs,
like [oracle-v2](https: //github.com/makerdao/oracles-v2). For this reason, by default, a response is returned as
the [NDJSON](https : //en.wikipedia.org/wiki/JSON_streaming) format. You can change the output format
to plain
, json
, ndjson
, or trace
using the --format
flag :
plain
- simple, human-readable format with only basic information.json
- json array with list of results.ndjson
- same asjson
but instead of array, elements are returned in new lines.trace
- used to debug price models, prints a detailed graph with all possible information.
gofer price
The price
command returns a price for one or more asset pairs.If no pairs are provided then prices for all asset
pairs defined in the config file will be returned.When at least one price fails to be retrieved correctly, then the
command returns a non-zero status code.
Return prices for given PAIRs.
Usage:
gofer prices [PAIR...] [flags]
Aliases:
prices, price
Flags:
-h, --help help for prices
Global Flags:
-c, --config string config file (default "./gofer.json")
-f, --format plain|trace|json|ndjson output format (default ndjson)
--log.format text|json log format
-v, --log.verbosity string verbosity level (default "info")
--norpc disable the use of RPC agent
JSON output for a single asset pair consists of the following fields:
type
- may beaggregator
ororigin
. Theaggregator
value means that a given price has been calculated based on other prices, theorigin
value is used when a price is returned directly from an origin.base
- the base asset name.quote
- the quote asset name.price
- the current asset price.bid
- the bid price, 0 if it is impossible to retrive or calculate bid price.ask
- the ask price, 0 if it is impossible to retrive or calculate ask price.vol24
- the volume from last 24 hours, 0 if it is impossible to retrieve or calculate volume.ts
- the date from which the price was retrieved.params
- the list of additional parameters, it always contains themethod
field for aggregators and theorigin
field for origins.error
- the optional error message, if this field is present, then price is not relaiable.price
- the list of prices used in calculation. For origins it's always empty.
Example JSON output for BTC/USD pair:
{
"type": "aggregator",
"base": "BTC",
"quote": "USD",
"price": 45242.13,
"bid": 45236.308,
"ask": 45239.98,
"vol24h": 0,
"ts": "2021-05-18T10:30:00Z",
"params": {
"method": "median",
"minimumSuccessfulSources": "3"
},
"prices": [
{
"type": "origin",
"base": "BTC",
"quote": "USD",
"price": 45227.05,
"bid": 45221.79,
"ask": 45227.05,
"vol24h": 8339.77051164,
"ts": "2021-05-18T10:31:16Z",
"params": {
"origin": "bitstamp"
}
},
{
"type": "origin",
"base": "BTC",
"quote": "USD",
"price": 45242.13,
"bid": 45236.308,
"ask": 45240.468,
"vol24h": 0,
"ts": "2021-05-18T10:31:18.687607Z",
"params": {
"origin": "bittrex"
}
}
]
}
Examples:
$ gofer price --format plain
BTC/USD 45291.110000
ETH/USD 3501.636879
$ gofer price BTC/USD --format trace
Price for BTC/USD:
───aggregator(method:median, minimumSuccessfulSources:3, pair:BTC/USD, price:45287.18, timestamp:2021-05-18T10:35:00Z)
├──origin(origin:bitstamp, pair:BTC/USD, price:45298.02, timestamp:2021-05-18T10:35:39Z)
├──origin(origin:bittrex, pair:BTC/USD, price:45287.18, timestamp:2021-05-18T10:35:43.335185Z)
├──origin(origin:coinbasepro, pair:BTC/USD, price:45282.53, timestamp:2021-05-18T10:35:43.285832Z)
├──origin(origin:gemini, pair:BTC/USD, price:45266.13, timestamp:2021-05-18T10:35:00Z)
└──origin(origin:kraken, pair:BTC/USD, price:45291.2, timestamp:2021-05-18T10:35:43.470442Z)
gofer pairs
The pairs
command can be used to check if there are defined price models for given pairs and also to debug existing
price models. When the price model is missing, then the command returns a non-zero status code. If no pairs are provided
then all asset pairs defined in the config file will be returned. In combination with the --format=trace
flag, the
command will return price models for given pairs.
List all supported asset pairs.
Usage:
gofer pairs [PAIR...] [flags]
Aliases:
pairs, pair
Flags:
-h, --help help for pairs
Global Flags:
-c, --config string config file (default "./gofer.json")
-f, --format plain|trace|json|ndjson output format (default ndjson)
--log.format text|json log format
-v, --log.verbosity string verbosity level (default "info")
--norpc disable the use of RPC agent
Examples:
$ gofer pairs
"BTC/USD"
"ETH/USD"
$ gofer pairs --format plain
BTC/USD
ETH/USD
$ gofer pair BTC/USD --format trace
Graph for BTC/USD:
───median(pair:BTC/USD)
├──origin(origin:bitstamp, pair:BTC/USD)
├──origin(origin:bittrex, pair:BTC/USD)
├──origin(origin:coinbasepro, pair:BTC/USD)
├──origin(origin:gemini, pair:BTC/USD)
└──origin(origin:kraken, pair:BTC/USD)
gofer agent
The agent
command runs Gofer in the agent mode.
Excessive use of the gofer price
command may invoke many API calls to external services which can lead to
rate-limiting. To avoid this, the prices that were previously retrieved can be reused and updated only as often as is
defined in the ttl
parameters. To do this, Gofer needs to be run in agent mode.
At first, the agent mode has to be enabled in the configuration file by adding the following field:
{
"gofer": {
"rpc": {
"address": "127.0.0.1:8080"
}
}
}
The above address is used as the listen address for the internal RPC server and as a server address for a client. Next,
you have to launch the agent using the gofer agent
command.
From now, the gofer price
command will retrieve asset prices from the agent instead of retrieving them directly from
the origins. If you want to temporarily disable this behavior you have to use the --norpc
flag.
License
Documentation ¶
There is no documentation for this package.