🚀 The Webb Relayer 🧑
Table of Contents
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.
- Private transaction relaying (of user bridge transactions like Tornado Cash’s relayer)
- Data querying (for zero-knowledge proof generation)
- Event listening, proposing, and signature relaying (of DKG proposals where the relayer acts like an oracle)
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.
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.
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 💬.
├── config.rs # Functionality related to parsing of configurable values.
├── context.rs # Access the parsed configuration and generate providers and wallets.
├── events_watcher # Sync to different network types (EVM, Substrate), and act on different events.
├── handler.rs # Logic for what to do when a client is interacting with this relayer.
├── main.rs # Build and start the relayer.
├── probe.rs # Debugging relayer lifecycle, sync state, or other relayer state.
├── service.rs # The entry for tasks once the relayer is operating.
├── store # Logic for storing information with different backends.
├── tx_queue.rs # A queue for orderly handling of transactions.
├── tx_relay # Transaction relay handlers for different chains and protocols
└── utils.rs # Common functionality.
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/envConfigure the Rust toolchain to default to the latest stable version, add nightly:
rustup default stable
rustup update
rustup update nightlyGreat! Now your Rust environment is ready! 🚀🚀
git clone https://github.com/webb-tools/relayer.git
cargo build --release
Eager to try out the Webb Relayer and see it in action? Run a relayer with our preset EVM tornado configuration to get up and running immediately.
./target/release/webb-relayer -c config/config-tornados/ethereum -vv
Hot Tip 🌶️: To increase the logger verbosity add additional
-vvvvduring start up command. You will now seeTRACElogs. Happy debugging!
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.
./target/release/webb-relayer -c config/local-substrate -vv
Webb Relayer is easy to run and with flexible config 👌. The first step is to create a config file.
Example:
- Create an
.envfile 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
jsonformat for the config files if you prefer that!
The table below documents all the configuration options available for both chain and contract set ups. For a completed example, check out Harmony's testnet configuration.
Note: You can also review the different chain configurations for EVM and Substrate.
| Field | Description | Optionality |
|---|---|---|
http-endpoint |
Http(s) Endpoint for quick Req/Res | Required |
ws-endpoint |
Websocket Endpoint for long living connections | Required |
explorer |
Block explorer, used for generating clickable links for transactions that happens on this chain. | Optional |
chain-id |
Chain specific id. | Required |
private-key |
The Private Key of this account on this network. See PrivateKey Docs for secure setup | Required |
beneficiary |
The address of the account that will receive relayer fees. | Optional |
runtime |
Indicates Substrate runtime to use | Required for Substrate |
suri |
Interprets a string in order to generate a key Pair. In the case that the pair can be expressed as a direct derivation from a seed | Required for Substrate |
pallets |
Supported pallets for a particular Substrate node | Optional |
| Field | Description | Optionality |
|---|---|---|
contract |
Chain contract. Must be either: - Anchor (tornado protocol) - SignatureBridge - GovernanceBravoDelegate |
Required |
address |
The address of this contract on this chain. | Required |
deployed-at |
The block number where this contract got deployed at. | Required |
size |
The size of this contract. Note: only available for Anchor and Anchor2 contracts. |
Optional |
events-watcher |
Control the events watcher for this contract. | Optional |
withdraw-fee-percentage |
The fee percentage that your account will receive when you relay a transaction over this chain. | Optional |
withdraw-gaslimit |
A hex value of the gaslimit when doing a withdraw relay transaction on this chain. | Optional |
proposal-signing-backend |
a value of ProposalSigingBackend (for example { type = "DKGNode", node = "dkg-node" }) |
Required if the contract is Anchor |
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:edgeNote: this uses the latest and pre-released version deployed from
mainbranch, changeedgeto 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.
The relayer has 3 endpoints available to query from. They are outlined below for your convenience.
Retrieving nodes IP address:
/api/v1/ip
Expected Response
{
"ip": "127.0.0.1"
}Retrieve relayer configuration
/api/v1/info
Expected Response
{
"evm": {
"rinkeby": {
"enabled": true,
"chainId": 4,
"beneficiary": "0x58fcd47ece3ed24ace88fee06efd90dcb38f541f",
"contracts": [{
"contract": "Tornado",
"address": "0x626fec5ffa7bf1ee8ced7dabde545630473e3abb",
"deployedAt": 8896800,
"eventsWatcher": {
"enabled": true,
"pollingInterval": 15000
},
"size": 0.1,
"withdrawFeePercentage": 0.05
}]
}
},
"substrate": {},
"experimental": {
"smart-anchor-updates": false,
"smart-anchor-updates-retries": 0
}
}Retrieve historical leaves cache
chain_idcontract address
/api/v1/leaves/4/0x626fec5ffa7bf1ee8ced7dabde545630473e3abb
Expected Response
{
"leaves": ["0x2e5c62af48845c095bfa9b90b8ec9f6b7bd98fb3ac2dd3039050a64b919951dd", "0x0f89f0ef52120b8db99f5bdbbdd4019b5ea4bcfef14b0c19d261268da8afdc24", "0x3007c62f678a503e568534487bc5b0bc651f37bbe1f34668b4c8a360f15ba3c3"],
"lastQueriedBlock": "0x9f30a8"
}The following instructions outlines how to run the relayer base test suite and E2E test suite.
cargo test
- Run
cargo build --features integration-tests - Run
cd tests && git submodule update --init --recursive - Run
yarn install(intestsdir) yarn test
- If you want to run a specific test run
yarn test -fgrep <UNIQUE_PART_OF_TEST_NAME>. - If you want to make the tests fail fast (fail on first error) run
yarn test --bail. - by default, tests runs in parallel, to disable that run
yarn test --parallel=false. - failing tests will keep retry before giving up, up to 5 times. To disable that use
yarn test --retries=0. - 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:
- Specifying the Alice node ports such as:
const aliceManualPorts = { ws: 9944, http: 9933, p2p: 30333 } - Specifying the Bob node ports such as:
const bobManualPorts = { ws: 9945, http: 9934, p2p: 30334 } - Make the
portsproperty value be thealiceManualPortsandbobManualPortsrespectively in theLocalNodeOptsconfig which is the parameter inLocalProtocolSubstrate.start() function - Specifying and setting
isManualflag to true in theLocalNodeOptsconfig which is the parameter inLocalProtocolSubstrate.start() function
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!
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.