Ethereum Relayer

NOTE: Ethereum Relayers is stripped down and modified version of the previous work by Snowfork Team, Polkadex uses the relayer and corresponding substrate lightclient for migrating ERC20 PDEX to Native PDEX.

Relayer service that streams transactions from blockchain networks, packages data into messages, and sends the packets to the correlated bridge component.

• Development
• Configuration
  • Secrets
• Build
• Run
• Tests

Development

This project requires the following tools for day to day development:

• Mage: Used for build tasks
• Revive: Used for linting instead of golint
• Subkey: Used for substrate key management

Please install them first.

Run mage to see a list of available tasks (building, testing, linting, etc).

To enable revive for linting in VS-code, add the following to your config:

{
    "go.lintTool": "revive",
    "go.lintFlags": [
        "-config=${workspaceFolder}/revive.toml"
    ],
}

Contract Bindings

The bindings in the contracts directory for our Ethereum contracts are dynamically generated.

Make sure you have the following dependencies installed:

Install jq:

sudo apt install jq

Install abigen:

go install github.com/ethereum/go-ethereum/cmd/abigen

Compile the contracts in the ethereum directory:

truffle compile --all

Generate the bindings:

go generate ./...

Configuration

Before running the relayer, it needs to be configured first. By default the configuration file is read from ~/.config/polkadex-eth-relay/config.toml, but this can be overriden by passing the --config PATH flag to the relayer binary.

Example Configuration:

[ethereum]
endpoint = "ws://localhost:8545/"
descendants-until-final = 3
beefylightclient = "0x8cF6147918A5CBb672703F879f385036f8793a24"

[ethereum.channels.basic]
inbound = "0x992B9df075935E522EC7950F37eC8557e86f6fdb"
outbound = "0x2ffA5ecdBe006d30397c7636d3e015EEE251369F"

[ethereum.channels.incentivized]
inbound = "0xFc97A6197dc90bef6bbEFD672742Ed75E9768553"
outbound = "0xEDa338E4dC46038493b885327842fD3E301CaB39"

[parachain]
endpoint = "ws://127.0.0.1:11144/"

[relaychain]
endpoint = "ws://127.0.0.1:9944/"

[database]
dialect = "sqlite3"
dbpath = "tmp.db"

NOTE: For development and testing, we use our E2E test stack described here. It automatically generates a suitable configuration for testing.

Secrets

The relayer requires secret keys for submitting transactions to both chains. It reads these keys from environment variables.

Example:

export BEEFY_RELAYER_ETHEREUM_KEY="0x935b65c833ced92c43ef9de6bff30703d941bd92a2637cb00cfad389f5862109"
export PARACHAIN_COMMITMENT_RELAYER_ETHEREUM_KEY="0x8013383de6e5a891e7754ae1ef5a21e7661f1fe67cd47ca8ebf4acd6de66879a"
export ARTEMIS_PARACHAIN_KEY="//Relay"
export ARTEMIS_RELAYCHAIN_KEY="//Alice"

Build

mage build

Run

Run the relayer with the configuration described in Configuration.

build/polkadex-eth-relay run --config config.toml

NOTE: On its first run, the relayer has to perform some initial computation relating to Ethereum PoW verification. This can take over 10 minutes to complete, and is not a sign that its stuck or frozen.

Tests

To run both unit and integration tests, run the following command:

mage test