adds simulation factory to builder

- adds initial implementation of simulator task to the builder

Author: dylanlott

Cargo.toml

@@ -38,6 +38,13 @@ alloy = { version = "0.12.6", features = [
     "serde",
 ] }
 
+trevm = { version = "0.19.12", features = [ "concurrent-db" ]}
+revm = { version = "19.5.0", features = [ "alloydb" ]} 
+
+# HACK: Update these to use main alloy package 
+alloy-provider = { version = "0.7.3" }
+alloy-eips = { version = "0.7.3" }
+
 aws-config = "1.1.7"
 aws-sdk-kms = "1.15.0"
 

src/lib.rs

@@ -27,5 +27,7 @@ pub mod tasks;
 /// Utilities.
 pub mod utils;
 
+use alloy_eips as _;
+use alloy_provider as _;
 /// Anonymous crate dependency imports.
 use openssl as _;

src/tasks/block.rs

@@ -43,6 +43,11 @@ impl InProgressBlock {
         self.transactions.is_empty()
     }
 
+    /// Returns the current list of transactions included in this block
+    pub fn transactions(&self) -> Vec<TxEnvelope> {
+        self.transactions.clone()
+    }
+
     /// Unseal the block
     fn unseal(&mut self) {
         self.raw_encoding.take();

src/tasks/mod.rs

@@ -15,3 +15,6 @@ pub mod submit;
 
 /// Tx polling task
 pub mod tx_poller;
+
+/// Tx and bundle simulation task
+pub mod simulator;

src/tasks/simulator.rs

@@ -0,0 +1,333 @@
+use crate::tasks::block::InProgressBlock;
+use alloy::consensus::TxEnvelope;
+use alloy::primitives::U256;
+use eyre::Result;
+use revm::{db::CacheDB, primitives::{address, Account, CfgEnv, ExecutionResult}, DatabaseRef};
+use std::{convert::Infallible, sync::Arc};
+use tokio::{select, sync::mpsc::UnboundedReceiver, task::JoinSet};
+use trevm::{
+    db::sync::{ConcurrentState, ConcurrentStateInfo},
+    revm::{
+        primitives::{EVMError, ResultAndState},
+        Database, DatabaseCommit, EvmBuilder,
+    },
+    BlockDriver, Cfg, DbConnect, EvmFactory, NoopBlock, TrevmBuilder, Tx,
+};
+
+/// Tracks the EVM state, score, and result of an EVM execution.
+/// Scores are assigned by the evaluation function, and are Ord
+/// or PartialOrd to allow for sorting.
+#[derive(Debug, Clone)]
+pub struct Best<T, S: PartialOrd + Ord = U256> {
+    /// The transaction being executed.
+    pub tx: Arc<T>,
+    /// The result and state of the execution.
+    pub result: ResultAndState,
+    /// The score calculated by the evaluation function.
+    pub score: S,
+}
+
+/// Binds a database and an extension together.
+#[derive(Debug, Clone)]
+pub struct SimulatorFactory<Db, Ext> {
+    /// The database state the execution is carried out on.
+    pub db: Db,
+    /// The extension, if any, provided to the trevm instance.
+    pub ext: Ext,
+}
+
+/// SimResult is an [`Option`] type that holds a tuple of a transaction and its associated
+/// state as a [`Db`] type updates if it was successfully executed.
+type SimResult<Db> = Option<(Best<TxEnvelope>, ConcurrentState<Arc<ConcurrentState<Db>>>)>;
+
+impl<Db, Ext> SimulatorFactory<Db, Ext>
+where
+    Ext: Send + Sync + Clone + 'static,
+    Db: Database + DatabaseRef + DatabaseCommit + Send + Sync + Clone + 'static,
+{
+    /// Creates a new Simulator factory out of the database and extension.
+    pub const fn new(db: Db, ext: Ext) -> Self {
+        Self { db, ext }
+    }
+
+    /// Spawns a trevm simulator that runs until `deadline` is hit.
+    /// * Spawn does not guarantee that a thread is finished before the deadline.
+    /// * This is intentional, so that it can maximize simulation time before the deadline.
+    /// * This function always returns whatever the latest finished in progress block is.
+    pub fn spawn<T, F>(
+        self,
+        mut inbound_tx: UnboundedReceiver<TxEnvelope>,
+        evaluator: Arc<F>,
+        deadline: tokio::time::Instant,
+    ) -> tokio::task::JoinHandle<InProgressBlock>
+    where
+        T: Tx,
+        F: Fn(&ResultAndState) -> U256 + Send + Sync + 'static,
+    {
+        tokio::spawn(async move {
+            // Spawn a join set to track all simulation threads
+            let mut join_set = JoinSet::new();
+
+            let mut best: Option<Best<TxEnvelope>> = None;
+
+            let mut block = InProgressBlock::new();
+
+            let sleep = tokio::time::sleep_until(deadline);
+            tokio::pin!(sleep);
+
+            loop {
+                select! {
+                    _ = &mut sleep => break,
+                    // Handle incoming
+                    tx = inbound_tx.recv() => {
+                        if let Some(inbound_tx) = tx {
+                            // Setup the simulation environment
+                            let sim = self.clone();
+                            let eval = evaluator.clone();
+                            let mut parent_db = Arc::new(sim.connect().unwrap());
+
+                            // Kick off the work in a new thread
+                            join_set.spawn(async move {
+                                let result = sim.simulate_tx(inbound_tx, eval, parent_db.child());
+
+                                if let Some((best, db)) = result {
+                                    if let Ok(()) = parent_db.merge_child(db) {
+                                        tracing::debug!("merging updated simulation state");
+                                        return Some(best)
+                                    }
+                                    tracing::error!("failed to update simulation state");
+                                    None
+                                } else {
+                                    None
+                                }
+                            });
+                        }
+                    }
+                    Some(result) = join_set.join_next() => {
+                        match result {
+                            Ok(Some(candidate)) => {
+                                tracing::info!(tx_hash = ?candidate.tx.tx_hash(), "ingesting transaction");
+                                block.ingest_tx(candidate.tx.as_ref());
+
+                                if candidate.score > best.as_ref().map(|b| b.score).unwrap_or_default() {
+                                    tracing::info!(score = ?candidate.score, "new best candidate found");
+                                    best = Some(candidate);
+                                }
+                            }
+                            Ok(None) => {
+                                tracing::debug!("simulation returned no result");
+                            }
+                            Err(e) => {
+                                tracing::error!("simulation task failed: {}", e);
+                            }
+                        }
+                    }
+                    else => break,
+                }
+            }
+
+            block
+        })
+    }
+
+    /// Simulates an inbound tx and applies its state if it's successfully simualted
+    pub fn simulate_tx<F>(
+        self,
+        tx: TxEnvelope,
+        evaluator: Arc<F>,
+        db: ConcurrentState<Arc<ConcurrentState<Db>>>,
+    ) -> SimResult<Db>
+    where
+        F: Fn(&ResultAndState) -> U256 + Send + Sync + 'static,
+        Db: Database + DatabaseRef + DatabaseCommit + Send + Sync + Clone + 'static,
+    {
+        let trevm_instance = EvmBuilder::default().with_db(db).build_trevm();
+
+        let result = trevm_instance
+            .fill_cfg(&PecorinoCfg)
+            .fill_block(&NoopBlock)
+            .fill_tx(&tx) // Use as_ref() to get &SimTxEnvelope from Arc
+            .run();
+
+        match result {
+            Ok(t) => {
+                // log and evaluate simulation results
+                tracing::info!(tx_hash = ?tx.clone().tx_hash(), "transaction simulated");
+                let result = t.result_and_state().clone();
+                tracing::debug!(gas_used = &result.result.gas_used(), "gas consumed");
+                let score = evaluator(&result);
+                tracing::debug!(score = ?score, "transaction evaluated");
+
+                // accept results
+                let t = t.accept();
+                let db = t.1.into_db();
+
+                // return the updated db with the candidate applied to its state
+                Some((Best { tx: Arc::new(tx), result, score }, db))
+            }
+            Err(e) => {
+                // if this transaction fails to run, log the error and return None
+                tracing::error!(err = ?e.as_transaction_error(), "failed to simulate tx");
+                None
+            }
+        }
+    }
+
+    /// Simulates an inbound bundle and applies its state if it's successfully simulated
+    pub fn simulate_bundle<T, F>(
+        &self,
+        _bundle: Arc<Vec<T>>,
+        _evaluator: Arc<F>,
+        _trevm_instance: trevm::EvmNeedsCfg<'_, (), ConcurrentState<CacheDB<Arc<Db>>>>,
+    ) -> Option<Best<Vec<T>>>
+    where
+        T: Tx + Send + Sync + 'static,
+        F: Fn(&ResultAndState) -> U256 + Send + Sync + 'static,
+    {
+        todo!("implement bundle handling")
+    }
+}
+
+/// Wraps a Db into an EvmFactory compatible [`Database`]
+impl<'a, Db, Ext> DbConnect<'a> for SimulatorFactory<Db, Ext>
+where
+    Db: Database + DatabaseRef + DatabaseCommit + Sync + Send + Clone + 'static,
+    Ext: Sync + Clone,
+{
+    type Database = ConcurrentState<Db>;
+    type Error = Infallible;
+
+    fn connect(&'a self) -> Result<Self::Database, Self::Error> {
+        let inner = ConcurrentState::new(self.db.clone(), ConcurrentStateInfo::default());
+        Ok(inner)
+    }
+}
+
+/// Makes a SimulatorFactory capable of creating and configuring trevm instances
+impl<'a, Db, Ext> EvmFactory<'a> for SimulatorFactory<Db, Ext>
+where
+    Db: Database + DatabaseRef + DatabaseCommit + Sync + Send + Clone + 'static,
+    Ext: Sync + Clone,
+{
+    type Ext = ();
+
+    /// Create makes a [`ConcurrentState`] database by calling connect
+    fn create(&'a self) -> Result<trevm::EvmNeedsCfg<'a, Self::Ext, Self::Database>, Self::Error> {
+        let db = self.connect()?;
+        let trevm = trevm::revm::EvmBuilder::default().with_db(db).build_trevm();
+        Ok(trevm)
+    }
+}
+
+/// A trait for extracting transactions from
+pub trait BlockExtractor<Ext, Db: Database + DatabaseCommit>: Send + Sync + 'static {
+    /// BlockDriver runs the transactions over the provided trevm instance.
+    type Driver: BlockDriver<Ext, Error<Db>: core::error::Error>;
+
+    /// Instantiate an configure a new [`trevm`] instance.
+    fn trevm(&self, db: Db) -> trevm::EvmNeedsBlock<'static, Ext, Db>;
+
+    /// Extracts transactions from the source.
+    ///
+    /// Extraction is infallible. Worst case it should return a no-op driver.
+    fn extract(&mut self, bytes: &[u8]) -> Self::Driver;
+}
+
+impl<Ext> BlockDriver<Ext> for InProgressBlock {
+    type Block = NoopBlock;
+
+    type Error<Db: Database + DatabaseCommit> = Error<Db>;
+
+    fn block(&self) -> &Self::Block {
+        &NoopBlock
+    }
+
+    /// Loops through the transactions in the block and runs them, accepting the state at the end
+    /// if it was successful and returning and erroring out otherwise.
+    fn run_txns<'a, Db: Database + DatabaseCommit>(
+        &mut self,
+        mut trevm: trevm::EvmNeedsTx<'a, Ext, Db>,
+    ) -> trevm::RunTxResult<'a, Ext, Db, Self> {
+        for tx in self.transactions().iter() {
+            if tx.recover_signer().is_ok() {
+                let sender = tx.recover_signer().unwrap();
+                tracing::info!(sender = ?sender, tx_hash = ?tx.tx_hash(), "simulating transaction");
+
+                let t = match trevm.run_tx(tx) {
+                    Ok(t) => t,
+                    Err(e) => {
+                        if e.is_transaction_error() {
+                            return Ok(e.discard_error());
+                        } else {
+                            return Err(e.err_into());
+                        }
+                    }
+                };
+
+                (_, trevm) = t.accept();
+            }
+        }
+        Ok(trevm)
+    }
+
+    fn post_block<Db: Database + DatabaseCommit>(
+        &mut self,
+        _trevm: &trevm::EvmNeedsBlock<'_, Ext, Db>,
+    ) -> Result<(), Self::Error<Db>> {
+        Ok(())
+    }
+}
+
+/// Defines the CfgEnv for Pecorino Network
+#[derive(Debug, Clone, Copy)]
+pub struct PecorinoCfg;
+
+impl Cfg for PecorinoCfg {
+    fn fill_cfg_env(&self, cfg_env: &mut CfgEnv) {
+        cfg_env.chain_id = 17003;
+    }
+}
+
+/// Wrap the EVM error in a database error type
+pub struct Error<Db: Database>(EVMError<Db::Error>);
+
+impl<Db> From<EVMError<Db::Error>> for Error<Db>
+where
+    Db: Database,
+{
+    fn from(e: EVMError<Db::Error>) -> Self {
+        Self(e)
+    }
+}
+
+impl<Db: Database> core::error::Error for Error<Db> {}
+
+impl<Db: Database> core::fmt::Debug for Error<Db> {
+    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
+        write!(f, "Error")
+    }
+}
+
+impl<Db: Database> core::fmt::Display for Error<Db> {
+    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
+        write!(f, "Error")
+    }
+}
+
+/// A simple evaluation function as a sane default.
+pub fn eval_fn(state: &ResultAndState) -> U256 {
+    // log the transaction results
+    match &state.result {
+        ExecutionResult::Success { .. } => println!("Execution was successful."),
+        ExecutionResult::Revert { .. } => println!("Execution reverted."),
+        ExecutionResult::Halt { .. } => println!("Execution halted."),
+    }
+
+    // return the target account balance
+    let target_addr = address!("0x0000000000000000000000000000000000000000");
+    let default_account = Account::default();
+    let target_account = state.state.get(&target_addr).unwrap_or(&default_account);
+    tracing::info!(balance = ?target_account.info.balance, "target account balance");
+
+    target_account.info.balance
+}