Mevboost relay implementation

[idatsy]

Describe the feature

Submitting mev-boost relays requires a signed BidTrace, a struct already defined in

reth/crates/rpc/rpc-types/src/relay.rs

Line 48 in c58cdf9

pub struct BidTrace {

as

reth/crates/rpc/rpc-types/src/relay.rs

Line 69 in c58cdf9

pub struct SignedBidTrace {

What is actually sent:

reth/crates/rpc/rpc-types/src/relay.rs

Line 76 in c58cdf9

pub struct SignedBidSubmission {

AFAIK there is no signing functionality etc which means block builders have to implement their own. Would be convenient to have a signing implementation on the BidTrace struct that take a BLS signing key and produce a SignedMessage.

Might as well include request-response pattern for the 5 relay endpoints (types are already defined in relay.rs so should be ez)

Happy to put together a PR for this if you'd like, as long as you are happy with the shape/approach.

sauce: I am running a reth builder and have currently rolled my own.

Would be a continuation on @mattsse #5568 as well

Additional context

Thinking something like this:

pub trait MevBoostRelayClient {
    type Error;

    /// Get a list of validator registrations for validators scheduled to propose in the current and next epoch.
    /// Used by builders to know when to submit bids for an upcoming proposal.
    /// Returns an array of validator registrations for the current and next epoch.
    /// Each entry includes a slot and the validator with assigned duty.
    /// Slots without a registered validator are omitted.
    fn get_validators(&self) -> Result<Vec<Validator>, Self::Error> {
        Err("Not implemented".into())
    }

    /// Submit a new block to the relay.
    /// Blocks can be submitted as JSON or SSZ, and optionally GZIP encoded.
    /// The relay will simulate the block to verify properties and proposer payment.
    /// For accountability, builder signature is over the SSZ encoded message.
    /// Any new submission by a builder will overwrite a previous one by the same builder_pubkey.
    fn submit_block(&self, block: SignedBidSubmission) -> Result<(), Self::Error> {
        Err("Not implemented".into())
    }

    /// Get payloads that were delivered to proposers.
    /// Payloads become available after the relay responds to a getPayload request from the proposer.
    fn get_payloads_delivered(&self) -> Result<Vec<ProposerPayloadsDeliveredQuery>, Self::Error> {
        Err("Not implemented".into())
    }

    /// Get builder bid submissions.
    /// Returns a list of builder bids without execution payloads.
    /// Only submissions that were successfully verified.
    fn get_builder_bids(&self) -> Result<Vec<BuilderBlocksReceivedQuery>, Self::Error> {
        Err("Not implemented".into())
    }

    /// Check that a validator is registered with the relay.
    /// Returns the latest validator registration for a given pubkey.
    fn check_validator_registration(&self, pubkey: PublicKey) -> Result<todo!("add missing struct"), Self::Error> {
        Err("Not implemented".into())
    }
}

Which I guess could be made more generic for consumers along the lines of:

pub trait MevBoostRelayClient {
    type Error;

    // Get a list of validator registrations for validators scheduled to propose in the current and next epoch.
    fn get_validators(&self) -> Result<Vec<Validator>, Self::Error>;

    // Submit a new block to the relay.
    fn submit_block(&self, block: SignedBidSubmission) -> Result<(), Self::Error>;

    // Get payloads that were delivered to proposers.
    fn get_payloads_delivered(&self) -> Result<Vec<ProposerPayloadsDeliveredQuery>, Self::Error>;

    // Get builder bid submissions.
    fn get_builder_bids(&self) -> Result<Vec<BuilderBlocksReceivedQuery>, Self::Error>;

    // Check that a validator is registered with the relay.
    fn check_validator_registration(&self, pubkey: PublicKey) -> Result<ValidatorRegistration, Self::Error>;
}

and then

pub struct ExampleMevBoostRelayClient {
    base_url: String,
}

impl ExampleMevBoostRelayClient {
    pub fn new(base_url: String) -> Self {
        ExampleMevBoostRelayClient { base_url }
    }
}

impl MevBoostRelayClient for ExampleMevBoostRelayClient {
    type Error = MyErrorType;

    fn get_validators(&self) -> Result<Vec<Validator>, Self::Error> {
        todo!("Implement get_validators")
    }

    fn submit_block(&self, block: SignedBidSubmission) -> Result<(), Self::Error> {
        todo!("Implement submit_block")
    }

    fn get_payloads_delivered(&self) -> Result<Vec<ProposerPayloadsDeliveredQuery>, Self::Error> {
        todo!("Implement get_payloads_delivered")
    }

    fn get_builder_bids(&self) -> Result<Vec<BuilderBlocksReceivedQuery>, Self::Error> {
        todo!("Implement get_builder_bids")
    }

    fn check_validator_registration(&self, pubkey: PublicKey) -> Result<ValidatorRegistration, Self::Error> {
        todo!("Implement check_validator_registration")
    }
}

or

impl<T: FullMevBoostRelayClient> MevBoostRelayClient for T {
    type Error = T::Error;

    fn get_validators(&self) -> Result<Vec<Validator>, Self::Error> {
        <Self as FullMevBoostRelayClient>::get_validators(self)
    }

    fn submit_block(&self, block: SignedBidSubmission) -> Result<(), Self::Error> {
        <Self as FullMevBoostRelayClient>::submit_block(self, block)
    }

    fn get_payloads_delivered(&self) -> Result<Vec<ProposerPayloadsDeliveredQuery>, Self::Error> {
        <Self as FullMevBoostRelayClient>::get_payloads_delivered(self)
    }

    fn get_builder_bids(&self) -> Result<Vec<BuilderBlocksReceivedQuery>, Self::Error> {
        <Self as FullMevBoostRelayClient>::get_builder_bids(self)
    }

    fn check_validator_registration(&self, pubkey: PublicKey) -> Result<ValidatorRegistration, Self::Error> {
        <Self as FullMevBoostRelayClient>::check_validator_registration(self, pubkey)
    }
}

[yash-atreya]

@mattsse If this is to be implemented, I can take this.

[idatsy]

@mattsse If this is to be implemented, I can take this.

I have already implemented this x) but happy to share/help you out