⚠️ Deprecated ⚠️

This repository has been deprecated in favour of a new Rust implementation.

Dex Price Estimator

A service estimating feasible sell prices for Gnosis Protocol.

API

The service exposes the following endpoints:

• GET /markets/<baseTokenId>-<quoteTokenId>[?atoms=true][&hops=<num>]: returns the transitive orderbook (containing bids and asks) for the given base and quote token
• GET /markets/<baseTokenId>-<quoteTokenId>/estimated-buy-amount/<sellAmountInQuoteToken>[?atoms=true][&hops=<num>]: estimates the buy amount (in base tokens) a user can set as a limit order while still expecting to be matched when selling the given amount of quote token.
• GET /metrics: Return Prometheus metrics

If atoms is set to true (for now this is the only implemented method) all amounts will be denominated in the smallest available unit (base quantity) of the token. If hops is set to a number smaller than the max-hops command line option with which the server is run, the transitive orderbook is limited to this many intermediate steps. Otherwise max-hops is used.

The token ID for a specific ERC20 address can be queried from the dex smart contract using tokenAddressToIdMap. A subset of tokens listed can also be found here

Development

Running the service

Available config params are:

Options:
  --version                Show version number                         [boolean]
  --ethereum-node-url      RPC endpoint to connect to                 [required]
  --page-size              The number of orders to fetch per page  [default: 50]
  --port                   Port to bind on                     [default: "8080"]
  --hops                   The number of intermediate orderbooks to look at when
                           computing the transitive one             [default: 2]
  --poll-frequency         The number of milliseconds to wait between two
                           orderbook fetches                    [default: 10000]
  --price-rounding-buffer  The safety margin to subtract from the estimated
                           price, in order to make it more likely to be matched
                                                                [default: 0.001]
  --verbosity              log level
         [choices: "TRACE", "DEBUG", "INFO", "WARN", "ERROR", "FATAL"] [default:
                                                                         "INFO"]

To run the service

yarn build
yarn start -- --ethereum-node-url <your endpoint>

Running the tests

We are using a long poll frequency because to fetch the orderbook only once.

export ETHEREUM_NODE_URL=<<your endpoint>> POLL_FREQUENCY=2147483647
yarn build
yarn test

Running benchmarks

yarn start -- --ethereum-node-url <your endpoint>
yarn bench