address review comments:

- JsonEncode error instead of unwrap() for both submit_block and
  register_validators
- json timeout budget now accounts for prior ssz attempt

Author: JasonVranek

crates/common/src/pbs/error.rs

@@ -15,6 +15,9 @@ pub enum PbsError {
     #[error("json decode error: {err:?}, raw: {raw}")]
     JsonDecode { err: serde_json::Error, raw: String },
 
+    #[error("json encode error: {0:?}")]
+    JsonEncode(serde_json::Error),
+
     #[error("ssz decode error: {err:?}, fork: {fork}")]
     SSZDecode { err: String, fork: ForkName },
 

crates/pbs/src/mev_boost/register_validator.rs

@@ -35,17 +35,19 @@ pub async fn register_validator<S: BuilderApiState>(
         .insert(HEADER_START_TIME_UNIX_MS, HeaderValue::from_str(&utcnow_ms().to_string())?);
     send_headers.insert(USER_AGENT, get_user_agent_with_version(&req_headers)?);
 
-    // prepare the body in advance, ugly dyn
-    let bodies: Box<dyn Iterator<Item = (usize, Bytes)>> =
+    // prepare the body in advance
+    let bodies: Vec<(usize, Bytes)> =
         if let Some(batch_size) = state.config.pbs_config.validator_registration_batch_size {
-            Box::new(registrations.chunks(batch_size).map(|batch| {
-                // SAFETY: unwrap is ok because we're serializing a &[serde_json::Value]
-                let body = serde_json::to_vec(batch).unwrap();
-                (batch.len(), Bytes::from(body))
-            }))
+            registrations
+                .chunks(batch_size)
+                .map(|batch| {
+                    let body = serde_json::to_vec(batch).map_err(PbsError::JsonEncode)?;
+                    Ok((batch.len(), Bytes::from(body)))
+                })
+                .collect::<Result<Vec<_>, PbsError>>()?
         } else {
-            let body = serde_json::to_vec(&registrations).unwrap();
-            Box::new(std::iter::once((registrations.len(), Bytes::from(body))))
+            let body = serde_json::to_vec(&registrations).map_err(PbsError::JsonEncode)?;
+            vec![(registrations.len(), Bytes::from(body))]
         };
     send_headers.insert(CONTENT_TYPE, HeaderValue::from_static("application/json"));
 

crates/pbs/src/mev_boost/submit_block.rs

@@ -377,12 +377,16 @@ async fn send_submit_block_impl(
             status = %res.status(),
             "relay rejected SSZ content-type, resubmitting block with JSON content-type"
         );
+        //  Sharing caller's timeout budget with SSZ attempt, so JSON gets the remaining time
+        let remaining_timeout_ms =
+            timeout_ms.saturating_sub(start_request.elapsed().as_millis() as u64);
+        let json_body = serde_json::to_vec(&signed_blinded_block).map_err(PbsError::JsonEncode)?;
         res = match relay
             .client
             .post(url.as_ref().clone())
-            .timeout(Duration::from_millis(timeout_ms))
+            .timeout(Duration::from_millis(remaining_timeout_ms))
             .headers(headers.clone())
-            .body(serde_json::to_vec(&signed_blinded_block).unwrap())
+            .body(json_body)
             .header(CONTENT_TYPE, EncodingType::Json.content_type_header())
             .send()
             .await