# README

Gravity Core

Additional versions:

RU version

Init ledger

gravity ledger --home={home} init --network=devnet

"--home" is the home directory for Gravity
"--network" is the network type to generate configs for

To initialize configuration of the ledger for devnet, use this command:

gravity ledger --home={home} init

To initialize configuration of the ledger for a custom network, use this command:

gravity ledger --home={home} init --network=custom

If the directory contains no privKey.json, it will be generated automatically.

Configuration files: genesis.json - the genesis block for the ledger

The structure of the configuration file is partly described here, but there are a couple of custom sections:

"сonsulsCount": 5, #number of consuls
"initScore": {
  "{pubKey of the validator}": {gravity score},
},
"oraclesAddressByValidator": {. # the public keys of validators in InitScore
  "{pubKey of the validator}": {
    "ethereum": "{pubKey ethereum}",
    "waves": "{pubKey waves}"
  }
}

config.json - configuration of the ledger node

The structure of the configuration file is partly described here, but there are a couple of custom sections:

"adapters": {
  "ethereum": {
    "nodeUrl": "", # ethereum node address
    "gravityContractAddress": "" # gravity contract ethereum address
  },
  "waves": {
    "NodeUrl": "", # waves node address
    "ChainId": "S", # chainId of the waves node
    "GravityContractAddress":  # gravity contract waves address
  }
}

key_state.json - the state of validator's key (tendermint)

node_key.json - the private key of the ledger node (tendermint)

In order for a validator to participate in consensus, it is necessary for others to grade its behavior (Gravity score). If the score of the validator is higher than 0, it is a full-fledged participant of consensus and it can qualify for a consul position.

RPC

There are two types of RPC in the Gravity ledger:

public, set up in config.json RPC
private, set up as a flag during launch. A standard value is 127.0.0.1:2500

Start ledger

gravity ledger --home={home} start --rpc="127.0.0.1:2500" --bootstrap="http://127.0.0.1:26657" 

home is the home directory for Gravity configuration files
rpc - host for the private rpc
bootstrap - public rpc bootstrap of the node that the validator will connect to

To launch the node in devnet, use this command:

gravity ledger —home={home} start

To launch the first node in the network:

gravity ledger —home={home} start --bootstrap=""

To launch all other nodes

gravity ledger —home={home} start --bootstrap={url of the public rpc of the first node in config.json}

—rpc="127.0.0.1:2500" - private rpc
—bootstrap="" - url of the bootstrap node to connect to

If you deploy the network locally, you can't set up more than two nodes on a single address (a Tendermint limitation).

Other information on node setup can be found here

Voting

To add a new validator to the consensus, it is necessary to vote for its gravity score The Gravity ledger needs to contain at least three validators.

To grade other node's behavior, send a request to the private RPC :

Route: http://{priv rpc host}/vote

{
  "votes": [
    {
      PubKey: {public key of the validator},
      Score: {your score from 0 to 100}
    }...
  ]
}

If the request does not contain a validator mentioned before, the grade will be changed to zero.

Create Nebula

To create a Nebula, send a request to the private RPC:

Route: http://{priv rpc host}//setNebula

{
  "NebulaId": "nebula address"
  "ChainType": "ethereum/waves"
  "MaxPulseCountInBlock": {the max amount of pulses in a block}
  "MinScore": {the minumal score to participate in a nebula}
}

Init oracle

gravity oracle --home={home} init <nebula address> <ethereum/waves> <url of the public rpc of the gravity ledger> <url of the target chain node> <url of the extractor>"

After the execution of the above command, the {home} directory will have a folder "nebulae" with a {nebula address}.json file. For a more custom setup, this file can be edited manually.