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Ethereum Relay

The relay node is responsible for message propagation. It mainly comprises of 2 programs:

  • Relay
  • Abci

Using marlinctl2​

Usage​

$ sudo ./marlinctl relay create --help
NAME:
   marlinctl relay create - create a new relay

USAGE:
   marlinctl relay create [command options] [arguments...]

OPTIONS:
   --chain value            --chain "<CHAIN>"
   --discovery-addrs value  --discovery-addrs "<IP1:PORT1>,<IP2:PORT2>,..." (default: "127.0.0.1:8002")
   --heartbeat-addrs value  --heartbeat-addrs "<IP1:PORT1>,<IP2:PORT2>,..." (default: "127.0.0.1:8003")
   --datadir value          --datadir "/path/to/datadir" (default: "~/.ethereum/")
   --discovery-port value   --discovery-port <PORT> (default: 0)
   --pubsub-port value      --pubsub-port <PORT> (default: 0)
   --address value          --address "0x..."
   --name value             --name "<NAME>"
   --version value          --version <NUMBER> (default: "latest")
   --abci-version value     --abci-version <NUMBER> (default: "latest")
   --help, -h               show help (default: false)

Run​

$ sudo ./marlinctl relay create --chain "eth"

The abci is automatically created.

Manually​

Build​

The relay executable is built as part of OpenWeaver. See the README for build instructions.

The abci is available here. Use only the "Building from source" instructions (not Installation).

Usage​

$ ./relay/eth_relay --help

USAGE: eth_relay [OPTIONS] discovery_addrs heartbeat_addrs datadir

OPTIONS:
    -p, --pubsub-port <pubsub_port>
    -d, --discovery-port <discovery_port>
    -a, --address <address>
    -h, --help <help>
    -v, --version <version>

ARGS:
    discovery_addrs
    heartbeat_addrs
    datadir

Run​

# Blockchain
$ ./geth --datadir /path/to/datadir/ --syncmode=light

# Relay
$ ./relay/eth_relay "127.0.0.1:8002" "127.0.0.1:8003" "/path/to/datadir/"

Discussion​

The relay executable takes 3 arguments:

  • discovery-addrs - Comma separated string of beacon addresses to initiate discovery
  • heartbeat-addrs - Comma separated string of beacon addresses to register with
  • datadir - Path to the data directory of the blockchain node

The relay executable also supports three optional command-line arguments:

  • --pubsub-port - To set the local port used for the message relay (default: 5000)
  • --discovery-port - To set the local port used to initiate discovery (default: 5002)
  • --address - To set the reward address for the incentivized testnet

Why is the blockchain node needed?​

The blockchain node is needed to detect spam. For supporting block propagation, the blockchain node can be a light client but to support transaction propagation, it needs to be a full node.

This is a temporary requirement and will eventually be replaced (or at the very least, decoupled) with better spam prevention measures (e.g. an onchain light client).