Webb Relayer 🕸️

🚀 The Webb Relayer 🧑‍✈️
_{⚠️ Beta Software ⚠️}

📖 Table of Contents

Getting Started 🎉

In the Webb Protocol, the relayer plays a variety of roles. This repo contains code for an Anchor Protcol oracle, transaction and data relayer, and protocol governance participant. The aim is that these can all be run exclusive to one another to ensure maximum flexibility of external participants to the Webb Protocol.

The relayer system is composed of three main components. Each of these components should be thought of as entirely separate because they could be handled by different entities entirely.

1. Private transaction relaying (of user bridge transactions like Tornado Cash’s relayer)
2. Data querying (for zero-knowledge proof generation)
3. Event listening, proposing, and signature relaying (of DKG proposals where the relayer acts like an oracle)

Transaction relaying role

Relayers who fulfill the role of a transaction relayer are responsible with exposing an API for clients who wish to relay their zero-knowledge transactions through and with submitting them. Relayers of this role must possess enough balance on the blockchains in which they will relay these transactions, since, after all, they must possess the native balance to pay the fees for these transactions. Relayers can be configured for any number of chains and protocols from mixers to variable anchors and run for individual chains or all of them that exist for a given bridged set of anchors.

Data querying role

Relayers who fulfill this role do so in conjunction with the transaction relaying role although it is not required to possess both. Namely, this role is concerned with listening to the events occurring within an Anchor Protocol instance and storing the data for clients who wish to quickly access it through traditional HTTP methods. This role is actively maintained and sees regular updates to how we hope to store and serve data in the future.

Oracle role

Relayers who fulfill the role of an oracle listen to the Anchor Protocol instances on the various chains the anchors exist on. When they hear of insertions into the anchors' merkle trees they handle them accordingly (as is implemented in the event watchers). Those playing this role then relay the anchor update information to other connected Anchors, the DKG governance system, and any other integration that gets implemented in this repo. Oracle relayers help keep the state of an Anchor Protocol instance up to date by ensuring that all anchors within an instance know about the latest state of their neighboring anchors.

For additional information, please refer to the Webb Relayer Rust Docs 📝. Have feedback on how to improve the relayer network? Or have a specific question to ask? Checkout the Relayer Feedback Discussion 💬.

Prerequisites

This repo uses Rust so it is required to have a Rust developer environment set up. First install and configure rustup:

# Install
curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh
# Configure
source ~/.cargo/env

Configure the Rust toolchain to default to the latest stable version, add nightly:

rustup default stable
rustup update
rustup update nightly

Great! Now your Rust environment is ready! 🚀🚀

Installation 💻

Unix (Linux, macOS, WSL2, ..)

git clone https://github.com/webb-tools/relayer.git

cargo build --release --features cli

Usage

Quick Start ⚡

Local EVM Setup

Eager to try out the Webb Relayer and see it in action? Run a relayer with our preset EVM Local Network configuration to get up and running immediately. You can follow this guide to use the relayer for the EVM bridge! You will have to configure an .env file in the root directory as well. See below configuration section for more details.

# Update your local env file
cp ./config/development/evm-localnet/.env.example .env
cargo run -- -c ./config/development/evm-localnet -vvv

Hot Tip 🌶️: To increase the logger verbosity add additional -vvvv during start up command. You will now see TRACE logs. Happy debugging!

Local Substrate Mixer

To use the relayer for our Substrate mixer, you will first need to start a local substrate node that integrates with our pallets webb-standalone-node. Once the Substrate node is started locally you can proceed to start the relayer. You can follow this guide to use the relayer for the Substrate mixer!

cargo run -- -c ./config/development/local-substrate -vvv

Run 🏃

Webb Relayer is easy to run and with flexible config 👌. The first step is to create a config file.

Example:

• Create an .env file with the following values for the networks you wish to support.

WEBB_EVM_<network>_ENABLED=true
WEBB_EVM_<network>_PRIVATE_KEY=<0X_PREFIXED_PRIVATE_KEY>

WEBB_EVM_<network>_BENEFICIARY=<0X_PREFIXED_ADDRESS>

Checkout config for useful default configurations for many networks. These config files can be changed to your preferences, and are enabled with the .env configuration listed above.

Then run:

webb-relayer -vv -c ./config

Hot Tip 🌶️: you could also use the json format for the config files if you prefer that!

Configuration

Note: You can also review the different chain configurations for EVM and Substrate.

• SubstrateConfig
• EvmChainConfig

Chain Configuration

Contract Configuration

Docker 🐳

To use Docker to run the relayer, you will need to specify a config file and provide an .env file as described above. Then proceed to save it into the config directory.

To run docker image:

docker run --rm -v "<ABSOLUTE_PATH_TO_CONFIGS_DIRECTORY>:/config" --env-file .env -p 9955:9955 ghcr.io/webb-tools/relayer:edge

Note: this uses the latest and pre-released version deployed from main branch, change edge to the latest stable release version.

This will mount a configuration files at the /config directory inside the container so it would allow it to read the configuration you added.

API 📡

The relayer has 3 endpoints available to query from. They are outlined below for your convenience.

Retrieving nodes IP address:

/api/v1/ip

{
  "ip": "127.0.0.1"
}

Retrieve relayer configuration

/api/v1/info

{
  "evm": {
      "rinkeby": {
          "enabled": true,
          "chainId": 4,
          "beneficiary": "0x58fcd47ece3ed24ace88fee06efd90dcb38f541f",
          "contracts": [{
              "contract": "Anchor",
              "address": "0x626fec5ffa7bf1ee8ced7dabde545630473e3abb",
              "deployedAt": 8896800,
              "eventsWatcher": {
                  "enabled": true,
                  "pollingInterval": 15000
              },
              "size": 0.1,
              "proposalSigningBackend": { "type": "DKGNode", "node": "dkg-local" },
              "withdrawFeePercentage": 0.05
          }]
      }
  },
  "substrate": {},
  "experimental": {
      "smart-anchor-updates": false,
      "smart-anchor-updates-retries": 0
  }
}

Retrieve historical leaves cache

Parameters

• target_system (Could be evm or substrate).
• chain_id
• contract_address

For evm

/api/v1/leaves/evm/4/0x626fec5ffa7bf1ee8ced7dabde545630473e3abb

For substrate

Note: Since substrate dosent have contract address we use tree_id

/api/v1/leaves/substrate/4/9

 {
  "leaves": ["0x2e5c62af48845c095bfa9b90b8ec9f6b7bd98fb3ac2dd3039050a64b919951dd", "0x0f89f0ef52120b8db99f5bdbbdd4019b5ea4bcfef14b0c19d261268da8afdc24", "0x3007c62f678a503e568534487bc5b0bc651f37bbe1f34668b4c8a360f15ba3c3"],
  "lastQueriedBlock": "0x9f30a8"
}

Testing 🧪

The following instructions outlines how to run the relayer base test suite and E2E test suite.

To run base tests

cargo test

To run E2E tests

First you will need protocol-substrate node, compiled locally (in release mode) and both the protocol-substrate and relayer project must be next to each other. The relayer must be compiled using --features integration-tests.

Here is the basic setup you will need:

1. Clone the Relayer repo git clone https://github.com/webb-tools/relayer.git
2. Clone Protocol Substrate node https://github.com/webb-tools/protocol-substrate.git
3. Then fetch the submodules for the node cd protocol-substrate && git submodule update --init
4. While you are there, build the standalone node cargo build --release -p webb-standalone-node
5. And then go back to the relayer cd ../relayer
6. Run cargo build --features integration-tests
7. Run cd tests && git submodule update --init --recursive
8. Run yarn install (in tests dir)
9. yarn test

Tips for E2E tests

1. If you want to run a specific test run yarn test -fgrep <UNIQUE_PART_OF_TEST_NAME>.
2. If you want to make the tests fail fast (fail on first error) run yarn test --bail.
3. by default, tests runs in parallel, to disable that run yarn test --parallel=false.
4. failing tests will keep retry before giving up, up to 5 times. To disable that use yarn test --retries=0.
5. You can combine all the tips above together, for more options see here

For the Substrate Mixer test, you can connect to your local chain manually by:

1. Specifying the Alice node ports such as:

const aliceManualPorts = { ws: 9944, http: 9933, p2p: 30333 };

2. Specifying the Bob node ports such as:

const bobManualPorts = { ws: 9945, http: 9934, p2p: 30334 };

3. Make the ports property value be the aliceManualPorts and bobManualPorts respectively in the LocalNodeOpts config which is the parameter in LocalProtocolSubstrate.start() method.
4. Specifying and setting isManual flag to true in the LocalNodeOpts config which is the parameter in LocalProtocolSubstrate.start() method.

Contributing

Interested in contributing to the Webb Relayer Network? Thank you so much for your interest! We are always appreciative for contributions from the open-source community!

If you have a contribution in mind, please check out our Contribution Guide for information on how to do so. We are excited for your first contribution!

License

Licensed under Apache 2.0 license.

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in this crate by you, as defined in the Apache 2.0 license, shall be licensed as above, without any additional terms or conditions.

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