Have coordinator publish batches to Substrate

coordinator/src/main.rs

@@ -429,10 +429,11 @@ pub async fn handle_processors<D: Db, Pro: Processors, P: P2p>(
           );
           // TODO: Also check the other KeyGenId fields
 
-          // TODO: Is this safe?
+          // TODO: Publish an unsigned TX with a Musig signature here, instead of on-chain voting
+          // That removes the need for this nonce
           let Ok(nonce) = serai.get_nonce(&substrate_signer.address()).await else {
-            log::error!("couldn't connect to Serai node to get nonce");
-            todo!(); // TODO
+            log::error!("couldn't get nonce from Serai node");
+            todo!()
           };
 
           let tx = serai
@@ -459,7 +460,7 @@ pub async fn handle_processors<D: Db, Pro: Processors, P: P2p>(
               log::info!("voted on key pair for {:?} in TX {}", id.set, hex::encode(hash))
             }
             Err(e) => {
-              log::error!("couldn't connect to Serai node to publish TX: {:?}", e);
+              log::error!("couldn't connect to Serai node to publish vote TX: {:?}", e);
               todo!(); // TODO
             }
           }
@@ -537,9 +538,33 @@ pub async fn handle_processors<D: Db, Pro: Processors, P: P2p>(
           }))
         }
       },
-      ProcessorMessage::Substrate(msg) => match msg {
-        // TODO
-        processor_messages::substrate::ProcessorMessage::Update { .. } => todo!(),
+      ProcessorMessage::Substrate(inner_msg) => match inner_msg {
+        processor_messages::substrate::ProcessorMessage::Update { key: _, batch } => {
+          assert_eq!(
+            batch.batch.network, msg.network,
+            "processor sent us a batch for a different network than it was for",
+          );
+          // TODO: Check this key's key pair's substrate key is authorized to publish batches
+          // TODO: Check the batch ID is an atomic increment
+
+          match serai.publish(&serai.execute_batch(batch.clone())).await {
+            Ok(hash) => {
+              log::info!(
+                "executed batch {:?} {} (block {}) in TX {}",
+                batch.batch.network,
+                batch.batch.id,
+                hex::encode(batch.batch.block),
+                hex::encode(hash),
+              )
+            }
+            Err(e) => {
+              log::error!("couldn't connect to Serai node to publish batch TX: {:?}", e);
+              todo!(); // TODO
+            }
+          }
+
+          None
+        }
       },
     };
 

substrate/client/src/serai/in_instructions.rs

@@ -33,7 +33,7 @@ impl Serai {
       .await
   }
 
-  pub fn execute_batch(&self, batch: SignedBatch) -> Result<Encoded, SeraiError> {
+  pub fn execute_batch(&self, batch: SignedBatch) -> Encoded {
     self.unsigned::<InInstructions, _>(&in_instructions::Call::<Runtime>::execute_batch { batch })
   }
 }

substrate/client/src/serai/mod.rs

@@ -269,7 +269,7 @@ impl Serai {
       .map_err(SeraiError::RpcError)
   }
 
-  fn unsigned<P: 'static, C: Encode>(&self, call: &C) -> Result<Encoded, SeraiError> {
+  fn unsigned<P: 'static, C: Encode>(&self, call: &C) -> Encoded {
     // TODO: Should Serai purge the old transaction code AND set this to 0/1?
     const TRANSACTION_VERSION: u8 = 4;
 
@@ -284,7 +284,7 @@ impl Serai {
     // Prefix the length
     let mut complete_bytes = scale::Compact(u32::try_from(bytes.len()).unwrap()).encode();
     complete_bytes.extend(bytes);
-    Ok(Encoded(complete_bytes))
+    Encoded(complete_bytes)
   }
 
   pub fn sign<S: Send + Sync + Signer<SeraiConfig>>(

substrate/client/tests/common/in_instructions.rs

@@ -31,8 +31,7 @@ pub async fn provide_batch(batch: Batch) -> [u8; 32] {
 
   let block = publish_tx(
     &serai
-      .execute_batch(SignedBatch { batch: batch.clone(), signature: pair.sign(&batch.encode()) })
-      .unwrap(),
+      .execute_batch(SignedBatch { batch: batch.clone(), signature: pair.sign(&batch.encode()) }),
   )
   .await;