Allow to configure a min priority fee (#2413)

# Description
We are seeing errors on Gnosis Chain where our priority fee is deemed
`TooLowToCompete`. Unfortunately, the `additional_tip_percentage` is
currently only applied to MEVBlocker txs (which don't exist on Gnosis
Chain). This is to avoid paying additional tip for public mempool
transactions (which don't require it). This PR allows configuring a
minimum absolute tip amount.

# Changes
- [x] Move `additional_tip_percentage` on the MEVBlocker config, as it's
only valid there
- [x] Introduce a new parameter `min_priority_fee` which is considered
for all mempool kinds

## How to test
- [x] adjust e2e test to run with new config and print settlement tx
receipt

crates/driver/example.toml

@@ -13,7 +13,6 @@ account = "0x0000000000000000000000000000000000000000000000000000000000000001" #
 
 [submission]
 gas-price-cap = "1000000000000"
-additional-tip-percentage = 0.05
 
 [[submission.mempool]]
 mempool = "public"
@@ -23,6 +22,7 @@ revert-protection = true
 mempool = "mev-blocker"
 url = "https://your.custom.rpc.endpoint"
 max-additional-tip = "5000000000"
+additional-tip-percentage = 0.05
 use-soft-cancellations = true
 
 [contracts] # Optionally override the contract addresses, necessary on less popular blockchains

crates/driver/src/boundary/mempool.rs

@@ -29,7 +29,7 @@ pub use {gas_estimation::GasPriceEstimating, solver::settlement_submission::Glob
 
 #[derive(Debug, Clone)]
 pub struct Config {
-    pub additional_tip_percentage: f64,
+    pub min_priority_fee: eth::U256,
     pub gas_price_cap: eth::U256,
     pub target_confirm_time: std::time::Duration,
     pub max_confirm_time: std::time::Duration,
@@ -52,6 +52,7 @@ pub enum Kind {
     MEVBlocker {
         url: reqwest::Url,
         max_additional_tip: eth::U256,
+        additional_tip_percentage: f64,
         use_soft_cancellations: bool,
     },
 }
@@ -152,7 +153,20 @@ impl Mempool {
         let gas_price_estimator = SubmitterGasPriceEstimator {
             inner: self.gas_price_estimator.as_ref(),
             max_fee_per_gas: max_fee_per_gas.min(self.config.gas_price_cap.to_f64_lossy()),
-            additional_tip_percentage_of_max_fee: self.config.additional_tip_percentage,
+            additional_tip_percentage_of_max_fee: match (
+                &self.config.kind,
+                settlement.boundary.revertable(),
+            ) {
+                (
+                    Kind::MEVBlocker {
+                        additional_tip_percentage,
+                        ..
+                    },
+                    true,
+                ) => *additional_tip_percentage,
+                (Kind::MEVBlocker { .. }, false) => 0.,
+                (Kind::Public(_), _) => 0.,
+            },
             max_additional_tip: match (&self.config.kind, settlement.boundary.revertable()) {
                 (
                     Kind::MEVBlocker {

crates/driver/src/domain/eth/gas.rs

@@ -126,7 +126,7 @@ impl From<EffectiveGasPrice> for GasPrice {
 /// `{max,max_priority,base}_fee_per_gas` as defined by EIP-1559.
 ///
 /// https://eips.ethereum.org/EIPS/eip-1559#specification
-#[derive(Debug, Clone, Copy)]
+#[derive(Debug, Clone, Copy, Ord, Eq, PartialEq, PartialOrd)]
 pub struct FeePerGas(pub Ether);
 
 impl FeePerGas {

crates/driver/src/infra/blockchain/gas.rs

@@ -20,6 +20,7 @@ pub struct GasPriceEstimator {
     pub(super) gas: Arc<NativeGasEstimator>,
     additional_tip: Option<AdditionalTip>,
     max_fee_per_gas: eth::U256,
+    min_priority_fee: eth::U256,
 }
 
 impl GasPriceEstimator {
@@ -31,28 +32,33 @@ impl GasPriceEstimator {
         );
         let additional_tip = mempools
             .iter()
-            .find(|mempool| matches!(mempool.kind, mempool::Kind::MEVBlocker { .. }))
-            .map(|mempool| {
-                (
-                    match mempool.kind {
-                        mempool::Kind::MEVBlocker {
-                            max_additional_tip, ..
-                        } => max_additional_tip,
-                        _ => unreachable!(),
-                    },
-                    mempool.additional_tip_percentage,
-                )
-            });
+            .filter_map(|mempool| match mempool.kind {
+                mempool::Kind::MEVBlocker {
+                    max_additional_tip,
+                    additional_tip_percentage,
+                    ..
+                } => Some((max_additional_tip, additional_tip_percentage)),
+                mempool::Kind::Public(_) => None,
+            })
+            .next();
         // Use the lowest max_fee_per_gas of all mempools as the max_fee_per_gas
         let max_fee_per_gas = mempools
             .iter()
             .map(|mempool| mempool.gas_price_cap)
             .min()
             .expect("at least one mempool");
+
+        // Use the highest min_priority_fee of all mempools as the min_priority_fee
+        let min_priority_fee = mempools
+            .iter()
+            .map(|mempool| mempool.min_priority_fee)
+            .max()
+            .expect("at least one mempool");
         Ok(Self {
             gas,
             additional_tip,
             max_fee_per_gas,
+            min_priority_fee,
         })
     }
 
@@ -78,7 +84,10 @@ impl GasPriceEstimator {
                 };
                 eth::GasPrice::new(
                     self.max_fee_per_gas.into(),
-                    eth::U256::from_f64_lossy(estimate.max_priority_fee_per_gas).into(),
+                    std::cmp::max(
+                        self.min_priority_fee.into(),
+                        eth::U256::from_f64_lossy(estimate.max_priority_fee_per_gas).into(),
+                    ),
                     eth::U256::from_f64_lossy(estimate.base_fee_per_gas).into(),
                 )
             })

crates/driver/src/infra/config/file/load.rs

@@ -254,7 +254,7 @@ pub async fn load(network: &blockchain::Network, path: &Path) -> infra::Config {
             .mempools
             .iter()
             .map(|mempool| mempool::Config {
-                additional_tip_percentage: config.submission.additional_tip_percentage,
+                min_priority_fee: config.submission.min_priority_fee,
                 gas_price_cap: config.submission.gas_price_cap,
                 target_confirm_time: config.submission.target_confirm_time,
                 max_confirm_time: config.submission.max_confirm_time,
@@ -280,10 +280,12 @@ pub async fn load(network: &blockchain::Network, path: &Path) -> infra::Config {
                     file::Mempool::MevBlocker {
                         url,
                         max_additional_tip,
+                        additional_tip_percentage,
                         use_soft_cancellations,
                     } => mempool::Kind::MEVBlocker {
                         url: url.to_owned(),
                         max_additional_tip: *max_additional_tip,
+                        additional_tip_percentage: *additional_tip_percentage,
                         use_soft_cancellations: *use_soft_cancellations,
                     },
                 },

crates/driver/src/infra/config/file/mod.rs

@@ -56,11 +56,11 @@ struct Config {
 #[derive(Debug, Default, Deserialize)]
 #[serde(rename_all = "kebab-case", deny_unknown_fields)]
 struct SubmissionConfig {
-    /// Additional tip in percentage of max_fee_per_gas we are willing to give
-    /// to miners above regular gas price estimation. Expects a floating point
-    /// value between 0 and 1.
-    #[serde(default = "default_additional_tip_percentage")]
-    additional_tip_percentage: f64,
+    /// The minimum priority fee in Gwei the solver is ensuring to pay in a
+    /// settlement.
+    #[serde(default)]
+    #[serde_as(as = "serialize::U256")]
+    min_priority_fee: eth::U256,
 
     /// The maximum gas price in Gwei the solver is willing to pay in a
     /// settlement.
@@ -107,6 +107,11 @@ enum Mempool {
         #[serde(default = "default_max_additional_tip")]
         #[serde_as(as = "serialize::U256")]
         max_additional_tip: eth::U256,
+        /// Additional tip in percentage of max_fee_per_gas we are giving to
+        /// MEVBlocker above regular gas price estimation. Expects a
+        /// floating point value between 0 and 1.
+        #[serde(default = "default_additional_tip_percentage")]
+        additional_tip_percentage: f64,
         /// Configures whether the submission logic is allowed to assume the
         /// submission nodes implement soft cancellations. With soft
         /// cancellations a cancellation transaction doesn't have to get mined

crates/driver/src/tests/setup/driver.rs

@@ -186,7 +186,6 @@ async fn create_config_file(
 
            [submission]
            gas-price-cap = "1000000000000"
-           additional-tip-percentage = 0.0
            logic = "native"
            "#,
         hex_address(blockchain.settlement.address()),
@@ -210,6 +209,7 @@ async fn create_config_file(
                     file,
                     r#"[[submission.mempool]]
                     mempool = "mev-blocker"
+                    additional-tip-percentage = 0.0
                     url = "{}"
                     "#,
                     url.clone().unwrap_or(blockchain.web3_url.clone()),

crates/driver/src/tests/setup/solver.rs

@@ -203,7 +203,7 @@ impl Solver {
             infra::blockchain::GasPriceEstimator::new(
                 rpc.web3(),
                 &[infra::mempool::Config {
-                    additional_tip_percentage: Default::default(),
+                    min_priority_fee: Default::default(),
                     gas_price_cap: eth::U256::MAX,
                     target_confirm_time: Default::default(),
                     max_confirm_time: Default::default(),