refactor(coprocessor): fetch expected senders from gateway config

Author: Eikix

coprocessor/fhevm-engine/gw-listener/src/bin/gw_listener.rs

@@ -94,11 +94,11 @@ struct Conf {
     ciphertext_commits_address: Option<Address>,
 
     #[arg(
-        long = "expected-coprocessor-tx-sender",
+        long,
         requires = "ciphertext_commits_address",
-        help = "Expected coprocessor tx-sender address. Repeat once per coprocessor."
+        help = "GatewayConfig contract address used to fetch coprocessor tx-senders"
     )]
-    expected_coprocessor_tx_senders: Vec<Address>,
+    gateway_config_address: Option<Address>,
 
     #[arg(
         long,
@@ -182,10 +182,9 @@ async fn main() -> anyhow::Result<()> {
     else {
         anyhow::bail!("--host-chain-id or CHAIN_ID env var is missing.")
     };
-    if conf.ciphertext_commits_address.is_some() && conf.expected_coprocessor_tx_senders.is_empty()
-    {
+    if conf.ciphertext_commits_address.is_some() && conf.gateway_config_address.is_none() {
         anyhow::bail!(
-            "--expected-coprocessor-tx-sender is required when --ciphertext-commits-address is set."
+            "--gateway-config-address is required when --ciphertext-commits-address is set."
         );
     }
     let config = ConfigSettings {
@@ -204,7 +203,7 @@ async fn main() -> anyhow::Result<()> {
         replay_skip_verify_proof: conf.replay_skip_verify_proof,
         log_last_processed_every_number_of_updates: conf.log_last_processed_every_number_of_updates,
         ciphertext_commits_address: conf.ciphertext_commits_address,
-        expected_coprocessor_tx_senders: conf.expected_coprocessor_tx_senders,
+        gateway_config_address: conf.gateway_config_address,
         drift_no_consensus_timeout_blocks: conf.drift_no_consensus_timeout_blocks,
         drift_post_consensus_grace_blocks: conf.drift_post_consensus_grace_blocks,
     };

coprocessor/fhevm-engine/gw-listener/src/gw_listener.rs

@@ -29,6 +29,7 @@ use crate::KeyType;
 use fhevm_engine_common::chain_id::ChainId;
 
 use fhevm_gateway_bindings::ciphertext_commits::CiphertextCommits;
+use fhevm_gateway_bindings::gateway_config::GatewayConfig;
 use fhevm_gateway_bindings::input_verification::InputVerification;
 use fhevm_gateway_bindings::kms_generation::KMSGeneration;
 
@@ -129,8 +130,9 @@ impl<P: Provider<Ethereum> + Clone + 'static, A: AwsS3Interface + Clone + 'stati
         let mut ticker = tokio::time::interval(self.conf.get_logs_poll_interval);
         let mut last_processed_block_num = self.get_last_processed_block_num(db_pool).await?;
         let mut number_of_last_processed_updates: u64 = 0;
+        let expected_coprocessor_tx_senders = self.fetch_expected_coprocessor_tx_senders().await?;
         let mut drift_detector = DriftDetector::new(
-            self.conf.expected_coprocessor_tx_senders.clone(),
+            expected_coprocessor_tx_senders,
             self.conf.host_chain_id,
             self.conf.drift_no_consensus_timeout_blocks,
             self.conf.drift_post_consensus_grace_blocks,
@@ -334,6 +336,24 @@ impl<P: Provider<Ethereum> + Clone + 'static, A: AwsS3Interface + Clone + 'stati
         Ok(())
     }
 
+    async fn fetch_expected_coprocessor_tx_senders(&self) -> anyhow::Result<Vec<Address>> {
+        let Some(gateway_config_address) = self.conf.gateway_config_address else {
+            return Ok(Vec::new());
+        };
+
+        let expected_coprocessor_tx_senders =
+            GatewayConfig::new(gateway_config_address, self.provider.clone())
+                .getCoprocessorTxSenders()
+                .call()
+                .await?;
+
+        if expected_coprocessor_tx_senders.is_empty() {
+            anyhow::bail!("GatewayConfig returned no coprocessor tx-senders");
+        }
+
+        Ok(expected_coprocessor_tx_senders)
+    }
+
     async fn verify_proof_request(
         &self,
         db_pool: &Pool<Postgres>,

coprocessor/fhevm-engine/gw-listener/src/lib.rs

@@ -58,7 +58,7 @@ pub struct ConfigSettings {
     pub log_last_processed_every_number_of_updates: u64,
 
     pub ciphertext_commits_address: Option<Address>,
-    pub expected_coprocessor_tx_senders: Vec<Address>,
+    pub gateway_config_address: Option<Address>,
     pub drift_no_consensus_timeout_blocks: u64,
     pub drift_post_consensus_grace_blocks: u64,
 }
@@ -96,7 +96,7 @@ impl Default for ConfigSettings {
             replay_skip_verify_proof: false,
             log_last_processed_every_number_of_updates: 50,
             ciphertext_commits_address: None,
-            expected_coprocessor_tx_senders: Vec::new(),
+            gateway_config_address: None,
             drift_no_consensus_timeout_blocks: 50,
             drift_post_consensus_grace_blocks: 10,
         }