krakenrs
========

Unofficial bindings to Kraken spot trading API in Rust.

This library provides a Rust client object implementing many of the calls from the [Kraken REST API](https://docs.kraken.com/rest/)
with an idiomatic Rust interface, including getting ticker info and making market and limit orders. Additionally it provides access
to the [Kraken WS API](https://docs.kraken.com/ws/), both subscribing to feeds and submitting orders.

- Requests and responses are strongly-typed, conversion done using [`serde_json`](https://docs.serde.rs/serde_json/)
- [`reqwest`](https://docs.rs/reqwest/0.11.0/reqwest/) is used for https
- [`tokio-tungstenite`](https://docs.rs/tokio-tungstenite/latest/tokio_tungstenite/) is used for websockets
- [`RustCrypto`](https://docs.rs/hmac/0.10.1/hmac/) crates used for the Kraken authentication scheme
- [`rust_decimal`](https://docs.rs/rust_decimal/latest/rust_decimal/) used to represent Decimal values from kraken
- [`log`](https://docs.rs/log/latest/log/) is used for logging
- Robust error handling

Both public and private APIs are supported, but not all the calls and options are exposed, only the ones that were needed.
If something you need is missing, patches are welcome! Just open a github issue or pull request.

Features
--------

To get the websockets API, the `"ws"` feature must be enabled. It is on by default.
Otherwise you only get the REST API, which can do all the same things (and more), but has more strict rate limits.

Threading
---------

Unlike some other bindings, these are not async APIs (although the websockets feeds are implicitly asynchronous).

We have chosen to create blocking APIs for the Kraken REST API version for a few reasons:
* simplicity
* ease of debugging
* when trying to make multiple private REST API calls in parallel, we often see invalid nonce errors
  this is because the nonces are based on timestamps, but when multiple requests are created and sent
  in parallel, this is inherently racy and sometimes the request with the higher nonce will be processed
  by kraken first, invalidating the others.

Additionally, the REST API has quite strict rate limits so making large numbers of requests
in parallel isn't really possible.

Instead, it seems better to lean on the Websockets API, which is easy to use whether you want to use
an async runtime or not, and not make lots of calls to the REST API.

Examples
--------

REST API:

```rs
    use krakenrs::{KrakenRestConfig, KrakenRestAPI};
    use serde_json::to_string_pretty;

    fn main() {
        let kc_config = KrakenRestConfig::default();
        let api = KrakenRestAPI::try_from(kc_config).expect("could not create kraken api");

        println!(
          to_string_pretty(
            api.asset_pairs(vec!["XBT/USD", "SOL/BTC"]).expect("api call failed")
          ).unwrap()
        );

        println!(
          to_string_pretty(
            api.ticker(vec!["XBT/USD"]).expect("api call failed")
          ).unwrap()
        );
    }
```

Websockets API:

```rs
use krakenrs::ws::{KrakenWsConfig, KrakenWsAPI};
use std::{
    time::Duration,
    thread,
};

fn main() {
    let pairs = vec!["USD/CAD".to_string()];

    let ws_config = KrakenWsConfig {
        subscribe_book: pairs.clone(),
        book_depth: 10,
        private: None
    };
    let api = KrakenWsAPI::new(ws_config).expect("could not connect to websockets api");

    loop {
        thread::sleep(Duration::from_millis(500));
        let books = api.get_all_books();

        for (pair, book) in books {
            println!("{}", pair);
            println!("{} bids:", pair);
            for (price, entry) in book.bid.iter() {
                println!("{}\t\t{}", price, entry.volume);
            }
            println!("{} asks:", pair);
            for (price, entry) in book.ask.iter() {
                println!("{}\t\t{}", price, entry.volume);
            }
            println!();
            if book.checksum_failed {
                println!("Checksum failed, aborting");
                return;
            }
        }
        if api.stream_closed() { return; }
    }
}
```

The `KrakenWsAPI` object spawns a worker thread internally which drives the websockets connection.
If you don't want that you can import the `KrakenWsClient` object instead and arrange the worker
thread as you like, while observing latest feed data in other threads using the handle to the `ApiResult` object.

Disclaimer
----------

Use at your own risk. If you build trading software using this component and you suffer a loss because of a bug, I am not responsible.

Rest API Demo
-------------

The `krak` binary target is a simple demo that can be used to exercise the rest API functionality.
It is a command-line target that can parse a credentials file, connect to kraken and make a single
API call, and print the response.

Usage:
- Build everything: `cargo build`.
- Run `./target/debug/krak --help` for usage information.
  For example, you can see the trading system's current status with
  `./krak system-status`, or see asset pairs and current prices with
  `./krak asset-pairs`, `./krak ticker AAVEUSD`
- If you want to use private APIs, go to your Kraken account and create an API key.
  Then create a json file with your credentials, with the following schema:
  ```
  {
     "key": "ASDF",
     "secret: "jklw=="
  }
  ```
- Private APIs are invoked for example like:
  `./krak path/to/creds get-open-orders`
  `./krak path/to/creds --validate market-buy 0.02 AAVEUSD`

Websockets Feed Demo
--------------------

The `krak-feed` binary target can subscribe to, and print the results of, websockets feeds.

Usage
- Build everything: `cargo build`.
- Run `./target/debug/krak-feed --help` for usage information.
  For example, `./krak-feed book XBT/USD` will display the bitcoin/USD order book continuously.

Other projects of interest
--------------------------

- [`dovahcrow kraken rust client`](https://github.com/dovahcrow/kraken-rs)
- [`async kraken ws`](https://crates.io/crates/async_kraken_ws)
- [`coinnect`](https://github.com/hugues31/coinnect)
- [`python3-krakenex`](https://github.com/veox/python3-krakenex)
- [`kraken_ws_orderbook`](https://github.com/jurijbajzelj/kraken_ws_orderbook)

Reference
---------

- [Kraken REST API Docs](https://docs.kraken.com/rest/)
- [Kraken WS API Docs](https://docs.kraken.com/websockets/#overview)