Rubix WVAP Oracle

• Implementation of a centralised Oracle which uses a VWAP (volume weighted average price) over a predefined period.
• Motivation for implimenting this is to minimise the risk of liquidations due to short-lived fluctuations in price.
• For more in depth information about the architecture see the /docs folder.

Quick Start Guide

Install and run the Lamden Block Service

Read more about the blockservice here : https://github.com/Lamden/lamden_block_service

Minimum Specs

The blockservice is a lightweight application, it will need a 2 core machine, with at least 25gb space. As the Lamden blockchain grows it will be necessary to upgrade the disk space.

Installation

Install Dependancies

1. Mongo DB (latest)
2. Nodejs and NPM
3. PM2 - https://pm2.keymetrics.io/docs/usage/quick-start/
4. Clone https://github.com/cloakdkiller/lamden_block_service.git to your host machine.

Configure PM2 process manager

1. From project root touch ecosystem.config.js
2. nano ecosystem.config.js
3. paste the below code and press ctrl-x to exit & confirm you want to save.

module.exports = {
  "apps" : [{
    "name"      : "block_service",
    "script"    : "npm run start",
    "env": {
      "NETWORK": "mainnet",
      "BLOCKSERVICE_HOST": "0.0.0.0",
    }}
  ]
}

Configure the firewall

I recommend you only allow connections from the machine which will be running the oracle process on ports 3535 & 3536

Running the app

1. Ensure mongo is running.sudo systemctl start mongod.service
2. From project root pm2 start ecosystem.config.js
3. pm2 save to set pm2 to run on system start.

Install and run the Oracle

Installation

Minimum Specs

The oracle is a lightweight application, it will need a 2 core machine, with at least 25gb space. This app does have a local DB which is it uses to store some state, as time goes on this may need to be upgraded.

Install Dependencies

1. Nodejs and NPM
2. PM2 - https://pm2.keymetrics.io/docs/usage/quick-start/
3. Clone this repository to your host machine.

Configure the application

Open ecosystem.config.js, edit required fields.

variable	explanation
block_service_urls	comma dilineated list of IP addresses e.g 0.0.0.0,78.4.2.3
check_eth_price_frequency	how often the ETH price is synced to the local DB
etherscan_api_key	get one here
network	mainnet or testnet
operator_sk	the SK which will be writing the value to the blockchain
operator_vk	VK of above.
amm_contract	the rocketswap contract, don't change this
oracle_contract	contract to call set_price on
vwap_period_seconds	How many seconds the VWAP is calculated over, default is 86400 (1 day)
vwap_submission_frequency	How often the VWAP is calculated and submitted to the blockchain in milliseconds
sync_trades_from_bs_frequency	how often the API will sync new trades from the block-service, in milliseconds. default 10,000
submit_vwap_to_blockchain	true or false. determines whether the application should submit values to the blockchain.

Configure the firewall

It's recommended that you block all incoming connections, except for SSH connections from whitelisted IP addresses, and port 3000, again whitelisted IP's only. Your cloud provider should provide an interface for this.

If you wish to provide a data visualisation in the rubix application, a sensible approach might be to :

• create a data-vis microservice on a seperate machine (perhaps the rubix UI server),
• microservice would forward api calls to the oracle process
• microservice IP would be whitelisted by the oracle firewall.

if the UI is experiencing significant load, a seperate instance of the oracle process could be created, with blockchain submission functionality disabled.

Running the app

• From the project root directory pm2 start ecosystem.config.js
• Configure this service to run at system startup pm2 save

API

There is a basic REST API, which allows querying values in the local DB. For convenience there is a swagger dashboard available at <server_ip>:3000/api, once the application is running.

This api could form the basis for basic data visualisations.