Add SSZ support to Builder API

ethereum/builder-specs#104

builder_api/Cargo.toml

@@ -11,10 +11,13 @@ anyhow = { workspace = true }
 bls = { workspace = true }
 clock = { workspace = true }
 derive_more = { workspace = true }
+enum-iterator = { workspace = true }
 helper_functions = { workspace = true }
 hex-literal = { workspace = true }
+http_api_utils = { workspace = true }
 itertools = { workspace = true }
 log = { workspace = true }
+mime = { workspace = true }
 prometheus_metrics = { workspace = true }
 reqwest = { workspace = true }
 serde = { workspace = true }

builder_api/src/api.rs

@@ -5,11 +5,16 @@ use anyhow::{bail, ensure, Result};
 use bls::PublicKeyBytes;
 use derive_more::Constructor;
 use helper_functions::{misc, signing::SignForAllForks};
+use http_api_utils::ETH_CONSENSUS_VERSION;
 use itertools::Itertools as _;
 use log::{debug, info};
+use mime::{APPLICATION_JSON, APPLICATION_OCTET_STREAM};
 use prometheus_metrics::Metrics;
-use reqwest::{Client, Response, StatusCode};
-use ssz::SszHash as _;
+use reqwest::{
+    header::{ACCEPT, CONTENT_TYPE},
+    Client, RequestBuilder, Response, StatusCode,
+};
+use ssz::{SszHash as _, SszRead as _, SszWrite as _};
 use thiserror::Error;
 use typenum::Unsigned as _;
 use types::{
@@ -29,7 +34,7 @@ use crate::{
     combined::{ExecutionPayloadAndBlobsBundle, SignedBuilderBid},
     consts::BUILDER_PROPOSAL_DELAY_TOLERANCE,
     unphased::containers::SignedValidatorRegistrationV1,
-    BuilderConfig,
+    BuilderApiFormat, BuilderConfig,
 };
 
 const REQUEST_TIMEOUT: Duration = Duration::from_secs(BUILDER_PROPOSAL_DELAY_TOLERANCE);
@@ -157,19 +162,26 @@ impl Api {
         debug!("getting execution payload header from {url}");
 
         let response = self
-            .client
-            .get(url.into_url())
-            .timeout(REQUEST_TIMEOUT)
+            .request_with_accept_header(self.client.get(url.into_url()).timeout(REQUEST_TIMEOUT))
             .send()
             .await?;
+
         let response = handle_error(response).await?;
 
         if response.status() == StatusCode::NO_CONTENT {
             info!("builder has no execution payload header available for slot {slot}");
             return Ok(None);
         }
 
-        let builder_bid = response.json::<SignedBuilderBid<P>>().await?;
+        let builder_bid = match self.config.builder_api_format {
+            BuilderApiFormat::Json => response.json().await?,
+            BuilderApiFormat::Ssz => {
+                let phase = http_api_utils::extract_phase_from_headers(response.headers())?;
+                let bytes = response.bytes().await?;
+
+                SignedBuilderBid::<P>::from_ssz(&phase, &bytes)?
+            }
+        };
 
         debug!("get_execution_payload_header response: {builder_bid:?}");
 
@@ -230,18 +242,33 @@ impl Api {
         let block_root = block.message().hash_tree_root();
         let slot = block.message().slot();
 
-        let response = self
-            .client
-            .post(url.into_url())
-            .json(block)
-            .timeout(remaining_time)
-            .send()
-            .await?;
+        let request = self.request_with_accept_header(
+            self.client
+                .post(url.into_url())
+                .timeout(remaining_time)
+                .header(ETH_CONSENSUS_VERSION, block.phase().as_ref()),
+        );
+
+        let request = match self.config.builder_api_format {
+            BuilderApiFormat::Json => request.json(block),
+            BuilderApiFormat::Ssz => request
+                .header(CONTENT_TYPE, APPLICATION_OCTET_STREAM.as_ref())
+                .body(block.to_ssz()?),
+        };
 
+        let response = request.send().await?;
         let response = handle_error(response).await?;
-        let response: WithBlobsAndMev<ExecutionPayload<P>, P> = response
-            .json::<ExecutionPayloadAndBlobsBundle<P>>()
-            .await?
+
+        let response: WithBlobsAndMev<ExecutionPayload<P>, P> =
+            match self.config.builder_api_format {
+                BuilderApiFormat::Json => response.json().await?,
+                BuilderApiFormat::Ssz => {
+                    let phase = http_api_utils::extract_phase_from_headers(response.headers())?;
+                    let bytes = response.bytes().await?;
+
+                    ExecutionPayloadAndBlobsBundle::<P>::from_ssz(&phase, &bytes)?
+                }
+            }
             .into();
 
         let execution_payload = &response.value;
@@ -266,6 +293,15 @@ impl Api {
         Ok(response)
     }
 
+    fn request_with_accept_header(&self, request_builder: RequestBuilder) -> RequestBuilder {
+        let accept_header = match self.config.builder_api_format {
+            BuilderApiFormat::Json => APPLICATION_JSON,
+            BuilderApiFormat::Ssz => APPLICATION_OCTET_STREAM,
+        };
+
+        request_builder.header(ACCEPT, accept_header.as_ref())
+    }
+
     fn url(&self, path: &str) -> Result<RedactingUrl> {
         self.config.builder_api_url.join(path).map_err(Into::into)
     }
@@ -345,6 +381,7 @@ mod tests {
     ) -> Result<(), BuilderApiError> {
         let api = BuilderApi::new(
             BuilderConfig {
+                builder_api_format: BuilderApiFormat::Json,
                 builder_api_url: "http://localhost"
                     .parse()
                     .expect("http://localhost should be a valid URL"),

builder_api/src/bellatrix/containers.rs

@@ -12,15 +12,16 @@ use types::{
 
 #[derive(Debug, Deserialize, Ssz)]
 #[serde(bound = "", deny_unknown_fields)]
-#[ssz(derive_read = false, derive_size = false, derive_write = false)]
+#[ssz(derive_write = false)]
 pub struct BuilderBid<P: Preset> {
     pub header: Box<ExecutionPayloadHeader<P>>,
     pub value: Wei,
     pub pubkey: PublicKeyBytes,
 }
 
-#[derive(Debug, Deserialize)]
+#[derive(Debug, Deserialize, Ssz)]
 #[serde(bound = "", deny_unknown_fields)]
+#[ssz(derive_write = false)]
 pub struct SignedBuilderBid<P: Preset> {
     pub message: BuilderBid<P>,
     pub signature: SignatureBytes,

builder_api/src/capella/containers.rs

@@ -11,15 +11,16 @@ use types::{
 
 #[derive(Debug, Deserialize, Ssz)]
 #[serde(bound = "", deny_unknown_fields)]
-#[ssz(derive_read = false, derive_size = false, derive_write = false)]
+#[ssz(derive_write = false)]
 pub struct BuilderBid<P: Preset> {
     pub header: Box<ExecutionPayloadHeader<P>>,
     pub value: Wei,
     pub pubkey: PublicKeyBytes,
 }
 
-#[derive(Debug, Deserialize)]
+#[derive(Debug, Deserialize, Ssz)]
 #[serde(bound = "", deny_unknown_fields)]
+#[ssz(derive_write = false)]
 pub struct SignedBuilderBid<P: Preset> {
     pub message: BuilderBid<P>,
     pub signature: SignatureBytes,

builder_api/src/combined.rs

@@ -1,6 +1,7 @@
 use bls::{PublicKeyBytes, SignatureBytes};
+use enum_iterator::Sequence;
 use serde::Deserialize;
-use ssz::ContiguousList;
+use ssz::{ContiguousList, ReadError, Size, SszRead, SszReadDefault, SszSize};
 use types::{
     bellatrix::containers::ExecutionPayload as BellatrixExecutionPayload,
     capella::containers::ExecutionPayload as CapellaExecutionPayload,
@@ -38,6 +39,40 @@ pub enum SignedBuilderBid<P: Preset> {
     Electra(ElectraSignedBuilderBid<P>),
 }
 
+impl<P: Preset> SszSize for SignedBuilderBid<P> {
+    // The const parameter should be `Self::VARIANT_COUNT`, but `Self` refers to a generic type.
+    // Type parameters cannot be used in `const` contexts until `generic_const_exprs` is stable.
+    const SIZE: Size = Size::for_untagged_union::<{ Phase::CARDINALITY - 2 }>([
+        BellatrixSignedBuilderBid::<P>::SIZE,
+        CapellaSignedBuilderBid::<P>::SIZE,
+        DenebSignedBuilderBid::<P>::SIZE,
+        ElectraSignedBuilderBid::<P>::SIZE,
+    ]);
+}
+
+impl<P: Preset> SszRead<Phase> for SignedBuilderBid<P> {
+    fn from_ssz_unchecked(phase: &Phase, bytes: &[u8]) -> Result<Self, ReadError> {
+        let block = match phase {
+            Phase::Phase0 => {
+                return Err(ReadError::Custom {
+                    message: "signed builder bid is not available in Phase 0",
+                });
+            }
+            Phase::Altair => {
+                return Err(ReadError::Custom {
+                    message: "signed builder bid is not available in Altair",
+                });
+            }
+            Phase::Bellatrix => Self::Bellatrix(SszReadDefault::from_ssz_default(bytes)?),
+            Phase::Capella => Self::Capella(SszReadDefault::from_ssz_default(bytes)?),
+            Phase::Deneb => Self::Deneb(SszReadDefault::from_ssz_default(bytes)?),
+            Phase::Electra => Self::Electra(SszReadDefault::from_ssz_default(bytes)?),
+        };
+
+        Ok(block)
+    }
+}
+
 impl<P: Preset> SignedBuilderBid<P> {
     #[must_use]
     pub(crate) const fn pubkey(&self) -> PublicKeyBytes {
@@ -126,6 +161,39 @@ pub enum ExecutionPayloadAndBlobsBundle<P: Preset> {
     Electra(DenebExecutionPayloadAndBlobsBundle<P>),
 }
 
+impl<P: Preset> SszSize for ExecutionPayloadAndBlobsBundle<P> {
+    // The const parameter should be `Self::VARIANT_COUNT`, but `Self` refers to a generic type.
+    // Type parameters cannot be used in `const` contexts until `generic_const_exprs` is stable.
+    const SIZE: Size = Size::for_untagged_union::<{ Phase::CARDINALITY - 3 }>([
+        BellatrixExecutionPayload::<P>::SIZE,
+        CapellaExecutionPayload::<P>::SIZE,
+        DenebExecutionPayloadAndBlobsBundle::<P>::SIZE,
+    ]);
+}
+
+impl<P: Preset> SszRead<Phase> for ExecutionPayloadAndBlobsBundle<P> {
+    fn from_ssz_unchecked(phase: &Phase, bytes: &[u8]) -> Result<Self, ReadError> {
+        let block = match phase {
+            Phase::Phase0 => {
+                return Err(ReadError::Custom {
+                    message: "execution payload and blobs bundle is not available in Phase 0",
+                });
+            }
+            Phase::Altair => {
+                return Err(ReadError::Custom {
+                    message: "execution payload and blobs bundle is not available in Altair",
+                });
+            }
+            Phase::Bellatrix => Self::Bellatrix(SszReadDefault::from_ssz_default(bytes)?),
+            Phase::Capella => Self::Capella(SszReadDefault::from_ssz_default(bytes)?),
+            Phase::Deneb => Self::Deneb(SszReadDefault::from_ssz_default(bytes)?),
+            Phase::Electra => Self::Electra(SszReadDefault::from_ssz_default(bytes)?),
+        };
+
+        Ok(block)
+    }
+}
+
 impl<P: Preset> From<ExecutionPayloadAndBlobsBundle<P>>
     for WithBlobsAndMev<ExecutionPayload<P>, P>
 {

builder_api/src/config.rs

@@ -1,12 +1,20 @@
-use derive_more::Debug;
+use derive_more::{Debug, Display, FromStr};
 use types::redacting_url::RedactingUrl;
 
 pub const DEFAULT_BUILDER_MAX_SKIPPED_SLOTS_PER_EPOCH: u64 = 8;
 pub const DEFAULT_BUILDER_MAX_SKIPPED_SLOTS: u64 = 3;
 
+#[derive(Clone, Debug, Default, Display, FromStr)]
+pub enum BuilderApiFormat {
+    #[default]
+    Json,
+    Ssz,
+}
+
 #[expect(clippy::struct_field_names)]
 #[derive(Clone, Debug)]
 pub struct Config {
+    pub builder_api_format: BuilderApiFormat,
     pub builder_api_url: RedactingUrl,
     pub builder_disable_checks: bool,
     pub builder_max_skipped_slots_per_epoch: u64,

builder_api/src/deneb/containers.rs

@@ -16,30 +16,34 @@ use types::{
 
 #[derive(Debug, Deserialize, Ssz)]
 #[serde(bound = "", deny_unknown_fields)]
+#[ssz(derive_write = false)]
 pub struct BuilderBid<P: Preset> {
     pub header: Box<ExecutionPayloadHeader<P>>,
     pub blob_kzg_commitments: ContiguousList<KzgCommitment, P::MaxBlobCommitmentsPerBlock>,
     pub value: Uint256,
     pub pubkey: PublicKeyBytes,
 }
 
-#[derive(Debug, Deserialize)]
+#[derive(Debug, Deserialize, Ssz)]
 #[serde(bound = "", deny_unknown_fields)]
+#[ssz(derive_write = false)]
 pub struct SignedBuilderBid<P: Preset> {
     pub message: BuilderBid<P>,
     pub signature: SignatureBytes,
 }
 
-#[derive(Debug, Deserialize)]
+#[derive(Debug, Deserialize, Ssz)]
 #[serde(bound = "", deny_unknown_fields)]
+#[ssz(derive_write = false)]
 pub struct BlobsBundle<P: Preset> {
     pub commitments: ContiguousList<KzgCommitment, P::MaxBlobCommitmentsPerBlock>,
     pub proofs: ContiguousList<KzgProof, P::MaxBlobsPerBlock>,
     pub blobs: ContiguousList<Blob<P>, P::MaxBlobsPerBlock>,
 }
 
-#[derive(Debug, Deserialize)]
+#[derive(Debug, Deserialize, Ssz)]
 #[serde(bound = "", deny_unknown_fields)]
+#[ssz(derive_write = false)]
 pub struct ExecutionPayloadAndBlobsBundle<P: Preset> {
     pub execution_payload: ExecutionPayload<P>,
     pub blobs_bundle: BlobsBundle<P>,

builder_api/src/electra/containers.rs

@@ -14,6 +14,7 @@ use types::{
 
 #[derive(Debug, Deserialize, Ssz)]
 #[serde(bound = "", deny_unknown_fields)]
+#[ssz(derive_write = false)]
 pub struct BuilderBid<P: Preset> {
     pub header: Box<ExecutionPayloadHeader<P>>,
     pub blob_kzg_commitments: ContiguousList<KzgCommitment, P::MaxBlobCommitmentsPerBlock>,
@@ -22,8 +23,9 @@ pub struct BuilderBid<P: Preset> {
     pub pubkey: PublicKeyBytes,
 }
 
-#[derive(Debug, Deserialize)]
+#[derive(Debug, Deserialize, Ssz)]
 #[serde(bound = "", deny_unknown_fields)]
+#[ssz(derive_write = false)]
 pub struct SignedBuilderBid<P: Preset> {
     pub message: BuilderBid<P>,
     pub signature: SignatureBytes,

builder_api/src/lib.rs

@@ -1,7 +1,7 @@
 pub use crate::{
     api::Api as BuilderApi,
     config::{
-        Config as BuilderConfig, DEFAULT_BUILDER_MAX_SKIPPED_SLOTS,
+        BuilderApiFormat, Config as BuilderConfig, DEFAULT_BUILDER_MAX_SKIPPED_SLOTS,
         DEFAULT_BUILDER_MAX_SKIPPED_SLOTS_PER_EPOCH,
     },
     consts::PREFERRED_EXECUTION_GAS_LIMIT,