Keeper

Keeper is an admin toolkit for incentive-following software services. Each Keeper service may depend on any of the common infrastructure services and utilities provided by the Keeper framework.

Examples of incentivised behavior include mining, staking, witnessing, or otherwise producing blocks, publishing price feeds, or poking smart contract systems such as Maker or the Ethereum Alarm Clock.

Since keepers want to run as many profitable services as possible, writing a Keeper plugin is a good way to ensure that any theoretically incentivized actions presented by your system actually get executed.

Getting started

To start the default set of Keeper services:

git clone https://github.com/nexusdev/keeper
make -C keeper install
keeper start

Keeper uses Docker to run and manage its services, so you need to install Docker before you can use keeper start, keeper stop, etc.

However, if you have the dependencies installed (see Dockerfile), you can also just run the Keeper services manually on your machine:

bin/keeper feedbase-service

The same configuration file (~/.keeper.json) is used in both cases.

Feedbase

Feedbase is a simple smart contract that lets anyone publish price feeds to the Ethereum blockchain. For information about how to claim your feed IDs, please see https://github.com/nexusdev/feedbase.

This service works as a simple loop which periodically updates a set of feeds specified in ~/.keeper.json, as in the following example:

{
  "feedbase": {
    "feeds": {
      "37": {
        "command": "keeper price USD/XBT",
        "type": "ufixed128x128",
        "expiration": 120,
        "interval": 60
      },
      "38": {
        "command": "keeper price XBT/ETH",
        "type": "ufixed192x64",
        "expiration": 300,
        "interval": 120
      }
    }
  }
}

By default, the Ethereum node at http://localhost:8545 is used. To change this, please set the variable ETH_RPC_URL. Currently, only one Ethereum account (specified by the ETH_ACCOUNT variable) can be used. This account must be the owner of all the price feeds.

Each value will be automatically converted into fixed-point notation according to the value of the type option for the feed in question. The expiration option specifies the number of seconds until each value expires, while interval specifies how often they are updated.