interop-node

README

InterOp Node

InterOp Node is an application that facilitates communication between Settlus and external chains, supporting multi-chain NFT interoperability.

Concepts

There are mainly two components in the InterOp Node: Subscriber and Feeder. The Subscriber is responsible for fetching information from external chains, and the Feeder is responsible for sending votes to Settlus.

Subscriber

Each subscriber retrieves block data and NFT ownership information from external blockchain networks. External blockchain's block information (hash and number) is stored in the cache. NFT owner information is always fetched from the external chain.

Supported chains:

• Ethereum

Cache

For each block, the subscriber stores the block hash and number in a memory cache. Each subscriber runs a separate goroutine to periodically check the latest block number and hash from the external chain and update the cache.

When initializing the cache, users can specify the cache size to limit memory usage.

Cache implementation: cache.go

Feeder

The Feeder sends votes to Settlus. There can be multiple topics for voting, but currently, there is only one topic: NFT Ownership.

1. The feeder fetches RoundInfo from the Settlus blockchain.
2. From the RoundInfo, the feeder checks if Settlus is in the VOTING period.

• If Settlus is in the VOTING period, the feeder submits the Vote TX to Settlus.
• If Settlus is not in the VOTING period, the feeder gathers block data from the chains and submits the Prevote TX to Settlus.
• If the feeder cannot send the vote appropriately, it submits an Abstain vote to Settlus.

How to Run

Initialize the config file. The config file will be located at ~/.interop/

./interop-node config init

Edit the config file with appropriate values and run the oracle feeder.

./interop-node start

Local Development

First, run local Settlus.

ignite chain serve

Create a feeder account.

settlusd keys add foo
- address: settlus1nyw0ruj3t5wdh9ycgcsxles6mpfz9xmk93m9cy
  name: foo
  pubkey: '{"@type":"/ethermint.crypto.v1.ethsecp256k1.PubKey","key":"A8KPbBSg2xj/OFCkgcN0doTTGD4MikLFmfjQy4CjQ/lw"}'
  type: local

Fund the feeder account.

settlusd tx bank send YOUR_KEY_WITH_FUND settlus1nyw0ruj3t5wdh9ycgcsxles6mpfz9xmk93m9cy 10setl --fees 0.001setl --keyring-backend test

Get the private key of the feeder account.

settlusd keys export foo --unarmored-hex --unsafe --keyring-backend test

WARNING: The private key will be exported as an unarmored hexadecimal string. USE AT YOUR OWN RISK. Continue? [y/N]: y
1b8dac2949968eae623859330172283d27dda8b496f1dae2cbed9b1bcce51cb1

Get the validator address.

settlusd q staking validators

...
  min_self_delegation: "1"
  operator_address: settlusvaloper12g8w5dr5jyncct8jwdxwsy2g9ktdrjjluy76df
  status: BOND_STATUS_BONDED
...

Set oracle feeder delegation.

settlusd tx oracle feeder-delegation-consent settlus1nyw0ruj3t5wdh9ycgcsxles6mpfz9xmk93m9cy --from YOUR_VALIDATOR --fees 0.01setl --keyring-backend test

Check if the oracle feeder delegation is set.

settlusd q oracle feeder-delegation settlusvaloper12g8w5dr5jyncct8jwdxwsy2g9ktdrjjluy76df

feeder_delegation:
  feeder_address: settlus1nyw0ruj3t5wdh9ycgcsxles6mpfz9xmk93m9cy
  validator_address: settlusvaloper12g8w5dr5jyncct8jwdxwsy2g9ktdrjjluy76df

Update config.yaml

settlus:
  chain_id: "settlus_5371-1"
  rpc_url: http://localhost:26657
  grpc_url: http://localhost:9090
  insecure: true
  avg_block_time: 5s
  voting_period: 10
  gas_limit: 200000
  fees:
    denom: asetl
    amount: "10000000000000"
feeder:
  address: settlus1nyw0ruj3t5wdh9ycgcsxles6mpfz9xmk93m9cy
  private_key: 1b8dac2949968eae623859330172283d27dda8b496f1dae2cbed9b1bcce51cb1 # <- example private key
  validator_address: settlusvaloper12g8w5dr5jyncct8jwdxwsy2g9ktdrjjluy76df
chains:
- chain_id: "1"
  chain_name: ethereum
  chain_type: ethereum
  rpc_url: https://mainnet.infura.io/v3/YOUR_INFURA_KEY
log_level: info

Run the oracle feeder.

./interop-node start