feat(client+host): Dynamic RollupConfig in bootloader (#439)

bin/client/Cargo.toml

@@ -22,6 +22,8 @@ spin.workspace = true
 async-trait.workspace = true
 tracing.workspace = true
 revm.workspace = true
+serde = { version = "1.0.208", default-features = false, features = ["derive"] }
+serde_json = { version = "1.0.125", default-features = false }
 
 # local
 kona-common = { path = "../../crates/common", version = "0.0.2" }
@@ -35,10 +37,6 @@ kona-executor = { path = "../../crates/executor", version = "0.0.1" }
 # external
 tracing-subscriber = { version = "0.3.18", optional = true }
 
-[dev-dependencies]
-serde = { version = "1.0.197", features = ["derive"] }
-serde_json = "1.0.117"
-
 [features]
 tracing-subscriber = ["dep:tracing-subscriber"]
 

bin/client/src/boot.rs

@@ -5,6 +5,7 @@ use alloy_primitives::{B256, U256};
 use anyhow::{anyhow, Result};
 use kona_preimage::{PreimageKey, PreimageOracleClient};
 use kona_primitives::RollupConfig;
+use tracing::warn;
 
 /// The local key ident for the L1 head hash.
 pub const L1_HEAD_KEY: U256 = U256::from_be_slice(&[1]);
@@ -89,8 +90,21 @@ impl BootInfo {
                 .try_into()
                 .map_err(|_| anyhow!("Failed to convert L2 chain ID to u64"))?,
         );
-        let rollup_config = RollupConfig::from_l2_chain_id(chain_id)
-            .ok_or_else(|| anyhow!("Failed to get rollup config for L2 Chain ID: {chain_id}"))?;
+
+        // Attempt to load the rollup config from the chain ID. If there is no config for the chain,
+        // fall back to loading the config from the preimage oracle.
+        let rollup_config = if let Some(config) = RollupConfig::from_l2_chain_id(chain_id) {
+            config
+        } else {
+            warn!(
+                target: "boot-loader",
+                "No rollup config found for chain ID {}, falling back to preimage oracle. This is insecure in production without additional validation!",
+                chain_id
+            );
+            let ser_cfg = oracle.get(PreimageKey::new_local(L2_ROLLUP_CONFIG_KEY.to())).await?;
+            serde_json::from_slice(&ser_cfg)
+                .map_err(|e| anyhow!("Failed to deserialize rollup config: {}", e))?
+        };
 
         Ok(Self { l1_head, l2_output_root, l2_claim, l2_claim_block, chain_id, rollup_config })
     }

bin/host/Cargo.toml

@@ -35,7 +35,8 @@ reqwest = "0.12"
 tokio = { version = "1.37.0", features = ["full"] }
 futures = "0.3"
 clap = { version = "4.5.4", features = ["derive", "env"] }
-serde = { version = "1.0.198", features = ["derive"] }
+serde = { version = "1.0.208", features = ["derive"] }
+serde_json = "1.0.125"
 tracing-subscriber = "0.3.18"
 command-fds = { version = "0.3", features = ["tokio"] }
 os_pipe = "1.2.1"

bin/host/src/cli/mod.rs

@@ -5,7 +5,9 @@ use crate::kv::{
     SplitKeyValueStore,
 };
 use alloy_primitives::B256;
+use anyhow::{anyhow, Result};
 use clap::{ArgAction, Parser};
+use kona_derive::types::RollupConfig;
 use serde::Serialize;
 use std::{path::PathBuf, sync::Arc};
 use tokio::sync::RwLock;
@@ -59,6 +61,9 @@ pub struct HostCli {
     /// Run in pre-image server mode without executing any client program. Defaults to `false`.
     #[clap(long)]
     pub server: bool,
+    /// Path to rollup config
+    #[clap(long)]
+    pub rollup_config_path: Option<PathBuf>,
 }
 
 impl HostCli {
@@ -86,4 +91,21 @@ impl HostCli {
 
         kv_store
     }
+
+    /// Reads the [RollupConfig] from the file system and returns it as a string.
+    pub fn read_rollup_config(&self) -> Result<RollupConfig> {
+        let path = self.rollup_config_path.as_ref().ok_or_else(|| {
+            anyhow::anyhow!(
+                "No rollup config path provided. Please provide a path to the rollup config."
+            )
+        })?;
+
+        // Read the serialized config from the file system.
+        let ser_config = std::fs::read_to_string(path)
+            .map_err(|e| anyhow!("Error reading RollupConfig file: {e}"))?;
+
+        // Deserialize the config and return it.
+        serde_json::from_str(&ser_config)
+            .map_err(|e| anyhow!("Error deserializing RollupConfig: {e}"))
+    }
 }

bin/host/src/kv/local.rs

@@ -31,7 +31,11 @@ impl KeyValueStore for LocalKeyValueStore {
             L2_CLAIM_KEY => Some(self.cfg.l2_claim.to_vec()),
             L2_CLAIM_BLOCK_NUMBER_KEY => Some(self.cfg.l2_block_number.to_be_bytes().to_vec()),
             L2_CHAIN_ID_KEY => Some(self.cfg.l2_chain_id.to_be_bytes().to_vec()),
-            L2_ROLLUP_CONFIG_KEY => unimplemented!("L2RollupConfig fetching in local store not implemented. Necessary for chain IDs without a known rollup config."),
+            L2_ROLLUP_CONFIG_KEY => {
+                let rollup_config = self.cfg.read_rollup_config().ok()?;
+                let serialized = serde_json::to_vec(&rollup_config).ok()?;
+                Some(serialized)
+            }
             _ => None,
         }
     }