Update minimum bid amount calculation (#107)

Author: danimhr

auction-server/src/auction.rs

@@ -559,22 +559,27 @@ async fn verify_bid_exceeds_gas_cost<G>(
     estimated_gas: U256,
     oracle: G,
     bid_amount: U256,
-    multiplier: U256,
 ) -> Result<(), RestError>
 where
     G: GasOracle,
 {
-    let (base_fee_per_gas, _) = oracle
+    let (maximum_gas_fee, priority_fee) = oracle
         .estimate_eip1559_fees()
         .await
         .map_err(|_| RestError::TemporarilyUnavailable)?;
-    let gas_price = base_fee_per_gas * estimated_gas;
-    if bid_amount >= gas_price * multiplier {
+
+    // To submit TOTAL_BIDS_PER_AUCTION together, each bid must cover the gas fee for all of the submitted bids.
+    // To make sure we cover the estimation errors, we add the priority_fee to the final potential gas fee.
+    // Therefore, the bid amount needs to be TOTAL_BIDS_PER_AUCTION times per potential gas fee.
+    let potential_gas_fee = maximum_gas_fee * U256::from(TOTAL_BIDS_PER_AUCTION) + priority_fee;
+    let minimum_bid_amount = potential_gas_fee * estimated_gas;
+
+    if bid_amount >= minimum_bid_amount {
         Ok(())
     } else {
         Err(RestError::BadParameters(format!(
-            "Insufficient bid amount. Based on the current gas fees, your bid should be larger than: {}",
-            gas_price * multiplier
+            "Insufficient bid amount based on the current gas fees. estimated gas usage: {}, maximum fee per gas: {}, priority fee per gas: {}, minimum bid amount: {}",
+            estimated_gas, maximum_gas_fee, priority_fee, minimum_bid_amount
         )))
     }
 }
@@ -670,11 +675,6 @@ pub async fn handle_bid(
         estimated_gas,
         EthProviderOracle::new(chain_store.provider.clone()),
         bid.amount,
-        // To submit TOTAL_BIDS_PER_AUCTION together, each bid must cover the gas fee for all of the submitted bids.
-        // Therefore, the bid amount needs to be TOTAL_BIDS_PER_AUCTION times the gas fee.
-        // In order to make sure estimation errors are covered, it is summed up with one.
-        // For example, if we are unable to submit the bid in the current block.
-        U256::from(TOTAL_BIDS_PER_AUCTION + 1),
     )
     .await?;
     // The transaction body size will be automatically limited when the gas is limited.

gas-oracle/src/lib.rs

@@ -71,8 +71,8 @@ pub fn eip1559_default_estimator(base_fee_per_gas: U256, rewards: Vec<Vec<U256>>
         U256::from(EIP1559_FEE_ESTIMATION_DEFAULT_PRIORITY_FEE),
     );
 
-    // Minimum of 6 blocks needed to double the base fee.
-    let potential_max_fee = base_fee_per_gas * 2;
+    // Minimum of 4 blocks needed to 1.6 the base fee.
+    let potential_max_fee = base_fee_per_gas * 16 / 10;
     (
         potential_max_fee + max_priority_fee_per_gas,
         max_priority_fee_per_gas,