Move consensus context service into a subcrate. (#318)

Co-authored-by: Boog900 <boog900@tutanota.com>

Cargo.lock

@@ -575,6 +575,7 @@ name = "cuprate-consensus"
 version = "0.1.0"
 dependencies = [
  "cfg-if",
+ "cuprate-consensus-context",
  "cuprate-consensus-rules",
  "cuprate-helper",
  "cuprate-test-utils",
@@ -587,12 +588,30 @@ dependencies = [
  "proptest",
  "proptest-derive",
  "rand",
- "randomx-rs",
  "rayon",
  "thiserror",
  "thread_local",
  "tokio",
  "tokio-test",
+ "tower 0.5.1",
+ "tracing",
+]
+
+[[package]]
+name = "cuprate-consensus-context"
+version = "0.1.0"
+dependencies = [
+ "cuprate-consensus-rules",
+ "cuprate-helper",
+ "cuprate-types",
+ "futures",
+ "hex",
+ "monero-serai",
+ "randomx-rs",
+ "rayon",
+ "thiserror",
+ "thread_local",
+ "tokio",
  "tokio-util",
  "tower 0.5.1",
  "tracing",
@@ -704,6 +723,7 @@ dependencies = [
  "clap",
  "cuprate-blockchain",
  "cuprate-consensus",
+ "cuprate-consensus-context",
  "cuprate-consensus-rules",
  "cuprate-helper",
  "cuprate-types",
@@ -972,6 +992,7 @@ dependencies = [
  "cuprate-async-buffer",
  "cuprate-blockchain",
  "cuprate-consensus",
+ "cuprate-consensus-context",
  "cuprate-consensus-rules",
  "cuprate-cryptonight",
  "cuprate-dandelion-tower",

Cargo.toml

@@ -5,6 +5,7 @@ members = [
 	"binaries/cuprated",
 	"constants",
 	"consensus",
+	"consensus/context",
 	"consensus/fast-sync",
 	"consensus/rules",
 	"cryptonight",

binaries/cuprated/Cargo.toml

@@ -11,6 +11,7 @@ repository = "https://github.com/Cuprate/cuprate/tree/main/binaries/cuprated"
 # TODO: after v1.0.0, remove unneeded dependencies.
 cuprate-consensus        = { path = "../../consensus" }
 cuprate-fast-sync        = { path = "../../consensus/fast-sync" }
+cuprate-consensus-context = { path = "../../consensus/context" }
 cuprate-consensus-rules  = { path = "../../consensus/rules" }
 cuprate-cryptonight      = { path = "../../cryptonight" }
 cuprate-helper           = { path = "../../helper" }

binaries/cuprated/src/blockchain/manager.rs

@@ -8,10 +8,11 @@ use tracing::error;
 
 use cuprate_blockchain::service::{BlockchainReadHandle, BlockchainWriteHandle};
 use cuprate_consensus::{
-    context::RawBlockChainContext, BlockChainContextRequest, BlockChainContextResponse,
-    BlockChainContextService, BlockVerifierService, ExtendedConsensusError, TxVerifierService,
-    VerifyBlockRequest, VerifyBlockResponse, VerifyTxRequest, VerifyTxResponse,
+    BlockChainContextRequest, BlockChainContextResponse, BlockChainContextService,
+    BlockVerifierService, ExtendedConsensusError, TxVerifierService, VerifyBlockRequest,
+    VerifyBlockResponse, VerifyTxRequest, VerifyTxResponse,
 };
+use cuprate_consensus_context::RawBlockChainContext;
 use cuprate_p2p::{
     block_downloader::{BlockBatch, BlockDownloaderConfig},
     BroadcastSvc, NetworkInterface,

binaries/cuprated/src/blockchain/manager/handler.rs

@@ -10,11 +10,11 @@ use tracing::info;
 
 use cuprate_blockchain::service::{BlockchainReadHandle, BlockchainWriteHandle};
 use cuprate_consensus::{
-    block::PreparedBlock, context::NewBlockData, transactions::new_tx_verification_data,
-    BlockChainContextRequest, BlockChainContextResponse, BlockVerifierService,
-    ExtendedConsensusError, VerifyBlockRequest, VerifyBlockResponse, VerifyTxRequest,
-    VerifyTxResponse,
+    block::PreparedBlock, transactions::new_tx_verification_data, BlockChainContextRequest,
+    BlockChainContextResponse, BlockVerifierService, ExtendedConsensusError, VerifyBlockRequest,
+    VerifyBlockResponse, VerifyTxRequest, VerifyTxResponse,
 };
+use cuprate_consensus_context::NewBlockData;
 use cuprate_helper::cast::usize_to_u64;
 use cuprate_p2p::{block_downloader::BlockBatch, constants::LONG_BAN, BroadcastRequest};
 use cuprate_types::{

binaries/cuprated/src/rpc/request/blockchain_context.rs

@@ -5,7 +5,7 @@ use std::convert::Infallible;
 use anyhow::Error;
 use tower::{Service, ServiceExt};
 
-use cuprate_consensus::context::{
+use cuprate_consensus_context::{
     BlockChainContext, BlockChainContextRequest, BlockChainContextResponse,
     BlockChainContextService,
 };

books/architecture/src/appendix/crates.md

@@ -16,7 +16,8 @@ cargo doc --open --package cuprate-blockchain
 | Crate | In-tree path | Purpose |
 |-------|--------------|---------|
 | [`cuprate-consensus`](https://doc.cuprate.org/cuprate_consensus) | [`consensus/`](https://github.com/Cuprate/cuprate/tree/main/consensus) | TODO
-| [`cuprate-consensus-rules`](https://doc.cuprate.org/cuprate_consensus_rules) | [`consensus/rules/`](https://github.com/Cuprate/cuprate/tree/main/consensus-rules) | TODO
+| [`cuprate-consensus-context`](https://doc.cuprate.org/cuprate_consensus_context) | [`consensus/context/`](https://github.com/Cuprate/cuprate/tree/main/consensus/context) | TODO
+| [`cuprate-consensus-rules`](https://doc.cuprate.org/cuprate_consensus_rules) | [`consensus/rules/`](https://github.com/Cuprate/cuprate/tree/main/consensus/rules) | TODO
 | [`cuprate-fast-sync`](https://doc.cuprate.org/cuprate_fast_sync) | [`consensus/fast-sync/`](https://github.com/Cuprate/cuprate/tree/main/consensus/fast-sync) | Fast block synchronization
 
 ## Networking

consensus/Cargo.toml

@@ -11,6 +11,7 @@ repository = "https://github.com/Cuprate/cuprate/tree/main/consensus"
 cuprate-helper = { path = "../helper", default-features = false, features = ["std", "asynch", "num"] }
 cuprate-consensus-rules = { path = "./rules", features = ["rayon"] }
 cuprate-types = { path = "../types" }
+cuprate-consensus-context = { path = "./context" }
 
 cfg-if = { workspace = true }
 thiserror = { workspace = true }
@@ -18,13 +19,10 @@ tower = { workspace = true, features = ["util"] }
 tracing = { workspace = true, features = ["std", "attributes"] }
 futures = { workspace = true, features = ["std", "async-await"] }
 
-randomx-rs = { workspace = true }
 monero-serai = { workspace = true, features = ["std"] }
 
 rayon = { workspace = true }
 thread_local = { workspace = true }
-tokio = { workspace = true, features = ["rt"] }
-tokio-util = { workspace = true }
 
 hex = { workspace = true }
 rand = { workspace = true }

consensus/context/Cargo.toml

@@ -0,0 +1,24 @@
+[package]
+name = "cuprate-consensus-context"
+version = "0.1.0"
+edition = "2021"
+license = "MIT"
+authors = ["SyntheticBird","Boog900"]
+
+[dependencies]
+cuprate-consensus-rules =  { path = "../rules", features = ["proptest"]}
+cuprate-helper = { path = "../../helper", default-features = false, features = ["std", "cast"] }
+cuprate-types = { path = "../../types", default-features = false }
+
+futures = { workspace = true, features = ["std", "async-await"] }
+tokio = { workspace = true, features = ["rt-multi-thread", "macros"]}
+tokio-util = { workspace = true }
+tower = { workspace = true, features = ["util"] }
+tracing = { workspace = true, features = ["std", "attributes"] }
+thiserror = { workspace = true }
+
+monero-serai = { workspace = true, features = ["std"] }
+randomx-rs = { workspace = true }
+rayon = { workspace = true }
+thread_local = { workspace = true }
+hex = { workspace = true }

consensus/context/src/alt_chains.rs

@@ -9,9 +9,8 @@ use cuprate_types::{
 };
 
 use crate::{
-    ExtendedConsensusError,
-    __private::Database,
-    context::{difficulty::DifficultyCache, rx_vms::RandomXVm, weight::BlockWeightsCache},
+    ContextCacheError, __private::Database, difficulty::DifficultyCache, rx_vms::RandomXVm,
+    weight::BlockWeightsCache,
 };
 
 pub(crate) mod sealed {
@@ -38,7 +37,7 @@ pub struct AltChainContextCache {
     pub chain_height: usize,
     /// The top hash of the alt chain.
     pub top_hash: [u8; 32],
-    /// The [`ChainID`] of the alt chain.
+    /// The [`ChainId`] of the alt chain.
     pub chain_id: Option<ChainId>,
     /// The parent [`Chain`] of this alt chain.
     pub parent_chain: Chain,
@@ -98,7 +97,7 @@ impl AltChainMap {
         &mut self,
         prev_id: [u8; 32],
         database: D,
-    ) -> Result<Box<AltChainContextCache>, ExtendedConsensusError> {
+    ) -> Result<Box<AltChainContextCache>, ContextCacheError> {
         if let Some(cache) = self.alt_cache_map.remove(&prev_id) {
             return Ok(cache);
         }
@@ -133,7 +132,7 @@ pub(crate) async fn get_alt_chain_difficulty_cache<D: Database + Clone>(
     prev_id: [u8; 32],
     main_chain_difficulty_cache: &DifficultyCache,
     mut database: D,
-) -> Result<DifficultyCache, ExtendedConsensusError> {
+) -> Result<DifficultyCache, ContextCacheError> {
     // find the block with hash == prev_id.
     let BlockchainResponse::FindBlock(res) = database
         .ready()
@@ -180,7 +179,7 @@ pub(crate) async fn get_alt_chain_weight_cache<D: Database + Clone>(
     prev_id: [u8; 32],
     main_chain_weight_cache: &BlockWeightsCache,
     mut database: D,
-) -> Result<BlockWeightsCache, ExtendedConsensusError> {
+) -> Result<BlockWeightsCache, ContextCacheError> {
     // find the block with hash == prev_id.
     let BlockchainResponse::FindBlock(res) = database
         .ready()

consensus/context/src/difficulty.rs

@@ -17,7 +17,7 @@ use cuprate_types::{
     Chain,
 };
 
-use crate::{Database, ExtendedConsensusError, HardFork};
+use crate::{ContextCacheError, Database, HardFork};
 
 /// The amount of blocks we account for to calculate difficulty
 const DIFFICULTY_WINDOW: usize = 720;
@@ -33,9 +33,9 @@ const DIFFICULTY_LAG: usize = 15;
 ///
 #[derive(Debug, Clone, Copy, Eq, PartialEq)]
 pub struct DifficultyCacheConfig {
-    pub(crate) window: usize,
-    pub(crate) cut: usize,
-    pub(crate) lag: usize,
+    pub window: usize,
+    pub cut: usize,
+    pub lag: usize,
 }
 
 impl DifficultyCacheConfig {
@@ -73,14 +73,13 @@ impl DifficultyCacheConfig {
 #[derive(Debug, Clone, Eq, PartialEq)]
 pub struct DifficultyCache {
     /// The list of timestamps in the window.
-    /// len <= [`DIFFICULTY_BLOCKS_COUNT`]
-    pub(crate) timestamps: VecDeque<u64>,
+    pub timestamps: VecDeque<u64>,
     /// The current cumulative difficulty of the chain.
-    pub(crate) cumulative_difficulties: VecDeque<u128>,
+    pub cumulative_difficulties: VecDeque<u128>,
     /// The last height we accounted for.
-    pub(crate) last_accounted_height: usize,
+    pub last_accounted_height: usize,
     /// The config
-    pub(crate) config: DifficultyCacheConfig,
+    pub config: DifficultyCacheConfig,
 }
 
 impl DifficultyCache {
@@ -91,7 +90,7 @@ impl DifficultyCache {
         config: DifficultyCacheConfig,
         database: D,
         chain: Chain,
-    ) -> Result<Self, ExtendedConsensusError> {
+    ) -> Result<Self, ContextCacheError> {
         tracing::info!("Initializing difficulty cache this may take a while.");
 
         let mut block_start = chain_height.saturating_sub(config.total_block_count());
@@ -134,7 +133,7 @@ impl DifficultyCache {
         &mut self,
         numb_blocks: usize,
         database: D,
-    ) -> Result<(), ExtendedConsensusError> {
+    ) -> Result<(), ContextCacheError> {
         let Some(retained_blocks) = self.timestamps.len().checked_sub(numb_blocks) else {
             // More blocks to pop than we have in the cache, so just restart a new cache.
             *self = Self::init_from_chain_height(
@@ -361,7 +360,7 @@ async fn get_blocks_in_pow_info<D: Database + Clone>(
     database: D,
     block_heights: Range<usize>,
     chain: Chain,
-) -> Result<(VecDeque<u64>, VecDeque<u128>), ExtendedConsensusError> {
+) -> Result<(VecDeque<u64>, VecDeque<u128>), ContextCacheError> {
     tracing::info!("Getting blocks timestamps");
 
     let BlockchainResponse::BlockExtendedHeaderInRange(ext_header) = database

consensus/context/src/hardforks.rs

@@ -9,7 +9,7 @@ use cuprate_types::{
     Chain,
 };
 
-use crate::{Database, ExtendedConsensusError};
+use crate::{ContextCacheError, Database};
 
 /// The default amount of hard-fork votes to track to decide on activation of a hard-fork.
 ///
@@ -21,9 +21,9 @@ const DEFAULT_WINDOW_SIZE: usize = 10080; // supermajority window check length -
 #[derive(Debug, Clone, Copy, Eq, PartialEq)]
 pub struct HardForkConfig {
     /// The network we are on.
-    pub(crate) info: HFsInfo,
+    pub info: HFsInfo,
     /// The amount of votes we are taking into account to decide on a fork activation.
-    pub(crate) window: usize,
+    pub window: usize,
 }
 
 impl HardForkConfig {
@@ -54,17 +54,17 @@ impl HardForkConfig {
 
 /// A struct that keeps track of the current hard-fork and current votes.
 #[derive(Debug, Clone, Eq, PartialEq)]
-pub(crate) struct HardForkState {
+pub struct HardForkState {
     /// The current active hard-fork.
-    pub(crate) current_hardfork: HardFork,
+    pub current_hardfork: HardFork,
 
     /// The hard-fork config.
-    pub(crate) config: HardForkConfig,
+    pub config: HardForkConfig,
     /// The votes in the current window.
-    pub(crate) votes: HFVotes,
+    pub votes: HFVotes,
 
     /// The last block height accounted for.
-    pub(crate) last_height: usize,
+    pub last_height: usize,
 }
 
 impl HardForkState {
@@ -74,7 +74,7 @@ impl HardForkState {
         chain_height: usize,
         config: HardForkConfig,
         mut database: D,
-    ) -> Result<Self, ExtendedConsensusError> {
+    ) -> Result<Self, ContextCacheError> {
         tracing::info!("Initializing hard-fork state this may take a while.");
 
         let block_start = chain_height.saturating_sub(config.window);
@@ -122,11 +122,11 @@ impl HardForkState {
     /// # Invariant
     ///
     /// This _must_ only be used on a main-chain cache.
-    pub(crate) async fn pop_blocks_main_chain<D: Database + Clone>(
+    pub async fn pop_blocks_main_chain<D: Database + Clone>(
         &mut self,
         numb_blocks: usize,
         database: D,
-    ) -> Result<(), ExtendedConsensusError> {
+    ) -> Result<(), ContextCacheError> {
         let Some(retained_blocks) = self.votes.total_votes().checked_sub(self.config.window) else {
             *self = Self::init_from_chain_height(
                 self.last_height + 1 - numb_blocks,
@@ -159,7 +159,7 @@ impl HardForkState {
     }
 
     /// Add a new block to the cache.
-    pub(crate) fn new_block(&mut self, vote: HardFork, height: usize) {
+    pub fn new_block(&mut self, vote: HardFork, height: usize) {
         // We don't _need_ to take in `height` but it's for safety, so we don't silently loose track
         // of blocks.
         assert_eq!(self.last_height + 1, height);
@@ -194,7 +194,7 @@ impl HardForkState {
     }
 
     /// Returns the current hard-fork.
-    pub(crate) const fn current_hardfork(&self) -> HardFork {
+    pub const fn current_hardfork(&self) -> HardFork {
         self.current_hardfork
     }
 }
@@ -205,7 +205,7 @@ async fn get_votes_in_range<D: Database>(
     database: D,
     block_heights: Range<usize>,
     window_size: usize,
-) -> Result<HFVotes, ExtendedConsensusError> {
+) -> Result<HFVotes, ContextCacheError> {
     let mut votes = HFVotes::new(window_size);
 
     let BlockchainResponse::BlockExtendedHeaderInRange(vote_list) = database

consensus/context/src/lib.rs

@@ -1,6 +1,6 @@
 //! # Blockchain Context
 //!
-//! This module contains a service to get cached context from the blockchain: [`BlockChainContext`].
+//! This crate contains a service to get cached context from the blockchain: [`BlockChainContext`].
 //! This is used during contextual validation, this does not have all the data for contextual validation
 //! (outputs) for that you will need a [`Database`].
 //!
@@ -18,14 +18,14 @@ use tokio::sync::mpsc;
 use tokio_util::sync::PollSender;
 use tower::Service;
 
-use cuprate_consensus_rules::{blocks::ContextToVerifyBlock, current_unix_timestamp, HardFork};
+use cuprate_consensus_rules::{
+    blocks::ContextToVerifyBlock, current_unix_timestamp, ConsensusError, HardFork,
+};
 
-use crate::{Database, ExtendedConsensusError};
-
-pub(crate) mod difficulty;
-pub(crate) mod hardforks;
-pub(crate) mod rx_vms;
-pub(crate) mod weight;
+pub mod difficulty;
+pub mod hardforks;
+pub mod rx_vms;
+pub mod weight;
 
 mod alt_chains;
 mod task;
@@ -36,13 +36,13 @@ use difficulty::DifficultyCache;
 use rx_vms::RandomXVm;
 use weight::BlockWeightsCache;
 
-pub(crate) use alt_chains::{sealed::AltChainRequestToken, AltChainContextCache};
+pub use alt_chains::{sealed::AltChainRequestToken, AltChainContextCache};
 pub use difficulty::DifficultyCacheConfig;
 pub use hardforks::HardForkConfig;
 pub use tokens::*;
 pub use weight::BlockWeightsCacheConfig;
 
-pub(crate) const BLOCKCHAIN_TIMESTAMP_CHECK_WINDOW: u64 = 60;
+pub const BLOCKCHAIN_TIMESTAMP_CHECK_WINDOW: u64 = 60;
 
 /// Config for the context service.
 pub struct ContextConfig {
@@ -91,7 +91,7 @@ impl ContextConfig {
 pub async fn initialize_blockchain_context<D>(
     cfg: ContextConfig,
     database: D,
-) -> Result<BlockChainContextService, ExtendedConsensusError>
+) -> Result<BlockChainContextService, ContextCacheError>
 where
     D: Database + Clone + Send + Sync + 'static,
     D::Future: Send + 'static,
@@ -414,3 +414,52 @@ impl Service<BlockChainContextRequest> for BlockChainContextService {
         .boxed()
     }
 }
+
+#[derive(Debug, thiserror::Error)]
+pub enum ContextCacheError {
+    /// A consensus error.
+    #[error("{0}")]
+    ConErr(#[from] ConsensusError),
+    /// A database error.
+    #[error("Database error: {0}")]
+    DBErr(#[from] tower::BoxError),
+}
+
+use __private::Database;
+
+pub mod __private {
+    use std::future::Future;
+
+    use cuprate_types::blockchain::{BlockchainReadRequest, BlockchainResponse};
+
+    /// A type alias trait used to represent a database, so we don't have to write [`tower::Service`] bounds
+    /// everywhere.
+    ///
+    /// Automatically implemented for:
+    /// ```ignore
+    /// tower::Service<BCReadRequest, Response = BCResponse, Error = tower::BoxError>
+    /// ```
+    pub trait Database:
+        tower::Service<
+        BlockchainReadRequest,
+        Response = BlockchainResponse,
+        Error = tower::BoxError,
+        Future = Self::Future2,
+    >
+    {
+        type Future2: Future<Output = Result<Self::Response, Self::Error>> + Send + 'static;
+    }
+
+    impl<
+            T: tower::Service<
+                BlockchainReadRequest,
+                Response = BlockchainResponse,
+                Error = tower::BoxError,
+            >,
+        > Database for T
+    where
+        T::Future: Future<Output = Result<Self::Response, Self::Error>> + Send + 'static,
+    {
+        type Future2 = T::Future;
+    }
+}

consensus/context/src/rx_vms.rs

@@ -26,10 +26,10 @@ use cuprate_types::{
     Chain,
 };
 
-use crate::{Database, ExtendedConsensusError};
+use crate::{ContextCacheError, Database};
 
 /// The amount of randomX VMs to keep in the cache.
-const RX_SEEDS_CACHED: usize = 2;
+pub const RX_SEEDS_CACHED: usize = 2;
 
 /// A multithreaded randomX VM.
 #[derive(Debug)]
@@ -72,14 +72,14 @@ impl RandomX for RandomXVm {
 /// The randomX VMs cache, keeps the VM needed to calculate the current block's proof-of-work hash (if a VM is needed) and a
 /// couple more around this VM.
 #[derive(Clone, Debug)]
-pub(crate) struct RandomXVmCache {
+pub struct RandomXVmCache {
     /// The top [`RX_SEEDS_CACHED`] RX seeds.  
-    pub(crate) seeds: VecDeque<(usize, [u8; 32])>,
+    pub seeds: VecDeque<(usize, [u8; 32])>,
     /// The VMs for `seeds` (if after hf 12, otherwise this will be empty).
-    pub(crate) vms: HashMap<usize, Arc<RandomXVm>>,
+    pub vms: HashMap<usize, Arc<RandomXVm>>,
 
     /// A single cached VM that was given to us from a part of Cuprate.
-    pub(crate) cached_vm: Option<([u8; 32], Arc<RandomXVm>)>,
+    pub cached_vm: Option<([u8; 32], Arc<RandomXVm>)>,
 }
 
 impl RandomXVmCache {
@@ -88,7 +88,7 @@ impl RandomXVmCache {
         chain_height: usize,
         hf: &HardFork,
         database: D,
-    ) -> Result<Self, ExtendedConsensusError> {
+    ) -> Result<Self, ContextCacheError> {
         let seed_heights = get_last_rx_seed_heights(chain_height - 1, RX_SEEDS_CACHED);
         let seed_hashes = get_block_hashes(seed_heights.clone(), database).await?;
 
@@ -125,18 +125,18 @@ impl RandomXVmCache {
     }
 
     /// Add a randomX VM to the cache, with the seed it was created with.
-    pub(crate) fn add_vm(&mut self, vm: ([u8; 32], Arc<RandomXVm>)) {
+    pub fn add_vm(&mut self, vm: ([u8; 32], Arc<RandomXVm>)) {
         self.cached_vm.replace(vm);
     }
 
     /// Creates a RX VM for an alt chain, looking at the main chain RX VMs to see if we can use one
     /// of them first.
-    pub(crate) async fn get_alt_vm<D: Database>(
+    pub async fn get_alt_vm<D: Database>(
         &self,
         height: usize,
         chain: Chain,
         database: D,
-    ) -> Result<Arc<RandomXVm>, ExtendedConsensusError> {
+    ) -> Result<Arc<RandomXVm>, ContextCacheError> {
         let seed_height = randomx_seed_height(height);
 
         let BlockchainResponse::BlockHash(seed_hash) = database
@@ -162,7 +162,7 @@ impl RandomXVmCache {
     }
 
     /// Get the main-chain `RandomX` VMs.
-    pub(crate) async fn get_vms(&mut self) -> HashMap<usize, Arc<RandomXVm>> {
+    pub async fn get_vms(&mut self) -> HashMap<usize, Arc<RandomXVm>> {
         match self.seeds.len().checked_sub(self.vms.len()) {
             // No difference in the amount of seeds to VMs.
             Some(0) => (),
@@ -214,7 +214,7 @@ impl RandomXVmCache {
     }
 
     /// Removes all the `RandomX` VMs above the `new_height`.
-    pub(crate) fn pop_blocks_main_chain(&mut self, new_height: usize) {
+    pub fn pop_blocks_main_chain(&mut self, new_height: usize) {
         self.seeds.retain(|(height, _)| *height < new_height);
         self.vms.retain(|height, _| *height < new_height);
     }
@@ -222,7 +222,7 @@ impl RandomXVmCache {
     /// Add a new block to the VM cache.
     ///
     /// hash is the block hash not the blocks proof-of-work hash.
-    pub(crate) fn new_block(&mut self, height: usize, hash: &[u8; 32]) {
+    pub fn new_block(&mut self, height: usize, hash: &[u8; 32]) {
         if is_randomx_seed_height(height) {
             tracing::debug!("Block {height} is a randomX seed height, adding it to the cache.",);
 
@@ -243,7 +243,7 @@ impl RandomXVmCache {
 
 /// Get the last `amount` of RX seeds, the top height returned here will not necessarily be the RX VM for the top block
 /// in the chain as VMs include some lag before a seed activates.
-pub(crate) fn get_last_rx_seed_heights(mut last_height: usize, mut amount: usize) -> Vec<usize> {
+pub fn get_last_rx_seed_heights(mut last_height: usize, mut amount: usize) -> Vec<usize> {
     let mut seeds = Vec::with_capacity(amount);
     if is_randomx_seed_height(last_height) {
         seeds.push(last_height);
@@ -268,7 +268,7 @@ pub(crate) fn get_last_rx_seed_heights(mut last_height: usize, mut amount: usize
 async fn get_block_hashes<D: Database + Clone>(
     heights: Vec<usize>,
     database: D,
-) -> Result<Vec<[u8; 32]>, ExtendedConsensusError> {
+) -> Result<Vec<[u8; 32]>, ContextCacheError> {
     let mut fut = FuturesOrdered::new();
 
     for height in heights {
@@ -281,7 +281,7 @@ async fn get_block_hashes<D: Database + Clone>(
             else {
                 panic!("Database sent incorrect response!");
             };
-            Result::<_, ExtendedConsensusError>::Ok(hash)
+            Result::<_, ContextCacheError>::Ok(hash)
         });
     }
 

consensus/context/src/task.rs

@@ -16,13 +16,10 @@ use cuprate_types::{
 };
 
 use crate::{
-    context::{
     alt_chains::{get_alt_chain_difficulty_cache, get_alt_chain_weight_cache, AltChainMap},
     difficulty, hardforks, rx_vms, weight, BlockChainContext, BlockChainContextRequest,
-        BlockChainContextResponse, ContextConfig, RawBlockChainContext, ValidityToken,
-        BLOCKCHAIN_TIMESTAMP_CHECK_WINDOW,
-    },
-    Database, ExtendedConsensusError,
+    BlockChainContextResponse, ContextCacheError, ContextConfig, Database, RawBlockChainContext,
+    ValidityToken, BLOCKCHAIN_TIMESTAMP_CHECK_WINDOW,
 };
 
 /// A request from the context service to the context task.
@@ -68,7 +65,7 @@ impl<D: Database + Clone + Send + 'static> ContextTask<D> {
     pub(crate) async fn init_context(
         cfg: ContextConfig,
         mut database: D,
-    ) -> Result<Self, ExtendedConsensusError> {
+    ) -> Result<Self, ContextCacheError> {
         let ContextConfig {
             difficulty_cfg,
             weights_config,

consensus/context/src/weight.rs

@@ -21,12 +21,12 @@ use cuprate_types::{
     Chain,
 };
 
-use crate::{Database, ExtendedConsensusError, HardFork};
+use crate::{ContextCacheError, Database, HardFork};
 
 /// The short term block weight window.
-const SHORT_TERM_WINDOW: usize = 100;
+pub const SHORT_TERM_WINDOW: usize = 100;
 /// The long term block weight window.
-const LONG_TERM_WINDOW: usize = 100000;
+pub const LONG_TERM_WINDOW: usize = 100000;
 
 /// Configuration for the block weight cache.
 ///
@@ -80,7 +80,7 @@ impl BlockWeightsCache {
         config: BlockWeightsCacheConfig,
         database: D,
         chain: Chain,
-    ) -> Result<Self, ExtendedConsensusError> {
+    ) -> Result<Self, ContextCacheError> {
         tracing::info!("Initializing weight cache this may take a while.");
 
         let long_term_weights = get_long_term_weight_in_range(
@@ -121,7 +121,7 @@ impl BlockWeightsCache {
         &mut self,
         numb_blocks: usize,
         database: D,
-    ) -> Result<(), ExtendedConsensusError> {
+    ) -> Result<(), ContextCacheError> {
         if self.long_term_weights.window_len() <= numb_blocks {
             // More blocks to pop than we have in the cache, so just restart a new cache.
             *self = Self::init_from_chain_height(
@@ -258,7 +258,7 @@ fn calculate_effective_median_block_weight(
 }
 
 /// Calculates a blocks long term weight.
-pub(crate) fn calculate_block_long_term_weight(
+pub fn calculate_block_long_term_weight(
     hf: HardFork,
     block_weight: usize,
     long_term_median: usize,
@@ -287,7 +287,7 @@ async fn get_blocks_weight_in_range<D: Database + Clone>(
     range: Range<usize>,
     database: D,
     chain: Chain,
-) -> Result<Vec<usize>, ExtendedConsensusError> {
+) -> Result<Vec<usize>, ContextCacheError> {
     tracing::info!("getting block weights.");
 
     let BlockchainResponse::BlockExtendedHeaderInRange(ext_headers) = database
@@ -311,7 +311,7 @@ async fn get_long_term_weight_in_range<D: Database + Clone>(
     range: Range<usize>,
     database: D,
     chain: Chain,
-) -> Result<Vec<usize>, ExtendedConsensusError> {
+) -> Result<Vec<usize>, ContextCacheError> {
     tracing::info!("getting block long term weights.");
 
     let BlockchainResponse::BlockExtendedHeaderInRange(ext_headers) = database

consensus/fast-sync/Cargo.toml

@@ -12,6 +12,7 @@ path = "src/create.rs"
 cuprate-blockchain          = { path = "../../storage/blockchain" }
 cuprate-consensus           = { path = ".." }
 cuprate-consensus-rules     = { path = "../rules" }
+cuprate-consensus-context   = { path = "../context" }
 cuprate-types               = { path = "../../types" }
 cuprate-helper              = { path = "../../helper", features = ["cast"] }
 

consensus/fast-sync/src/fast_sync.rs

@@ -12,10 +12,8 @@ use monero_serai::{
 };
 use tower::{Service, ServiceExt};
 
-use cuprate_consensus::{
-    context::{BlockChainContextRequest, BlockChainContextResponse},
-    transactions::new_tx_verification_data,
-};
+use cuprate_consensus::transactions::new_tx_verification_data;
+use cuprate_consensus_context::{BlockChainContextRequest, BlockChainContextResponse};
 use cuprate_consensus_rules::{miner_tx::MinerTxError, ConsensusError};
 use cuprate_helper::cast::u64_to_usize;
 use cuprate_types::{VerifiedBlockInformation, VerifiedTransactionInformation};

consensus/src/block.rs

@@ -14,6 +14,9 @@ use monero_serai::{
 };
 use tower::{Service, ServiceExt};
 
+use cuprate_consensus_context::{
+    BlockChainContextRequest, BlockChainContextResponse, RawBlockChainContext,
+};
 use cuprate_helper::asynch::rayon_spawn_async;
 use cuprate_types::{
     AltBlockInformation, TransactionVerificationData, VerifiedBlockInformation,
@@ -30,7 +33,6 @@ use cuprate_consensus_rules::{
 };
 
 use crate::{
-    context::{BlockChainContextRequest, BlockChainContextResponse, RawBlockChainContext},
     transactions::{VerifyTxRequest, VerifyTxResponse},
     Database, ExtendedConsensusError,
 };

consensus/src/block/alt_block.rs

@@ -7,6 +7,12 @@ use std::{collections::HashMap, sync::Arc};
 use monero_serai::{block::Block, transaction::Input};
 use tower::{Service, ServiceExt};
 
+use cuprate_consensus_context::{
+    difficulty::DifficultyCache,
+    rx_vms::RandomXVm,
+    weight::{self, BlockWeightsCache},
+    AltChainContextCache, AltChainRequestToken, BLOCKCHAIN_TIMESTAMP_CHECK_WINDOW,
+};
 use cuprate_consensus_rules::{
     blocks::{
         check_block_pow, check_block_weight, check_timestamp, randomx_seed_height, BlockError,
@@ -22,12 +28,6 @@ use cuprate_types::{
 
 use crate::{
     block::{free::pull_ordered_transactions, PreparedBlock},
-    context::{
-        difficulty::DifficultyCache,
-        rx_vms::RandomXVm,
-        weight::{self, BlockWeightsCache},
-        AltChainContextCache, AltChainRequestToken, BLOCKCHAIN_TIMESTAMP_CHECK_WINDOW,
-    },
     BlockChainContextRequest, BlockChainContextResponse, ExtendedConsensusError,
     VerifyBlockResponse,
 };

consensus/src/block/batch_prepare.rs

@@ -5,6 +5,7 @@ use rayon::prelude::*;
 use tower::{Service, ServiceExt};
 use tracing::instrument;
 
+use cuprate_consensus_context::rx_vms::RandomXVm;
 use cuprate_consensus_rules::{
     blocks::{check_block_pow, is_randomx_seed_height, randomx_seed_height, BlockError},
     hard_forks::HardForkError,
@@ -15,7 +16,6 @@ use cuprate_helper::asynch::rayon_spawn_async;
 
 use crate::{
     block::{free::pull_ordered_transactions, PreparedBlock, PreparedBlockExPow},
-    context::rx_vms::RandomXVm,
     transactions::new_tx_verification_data,
     BlockChainContextRequest, BlockChainContextResponse, ExtendedConsensusError,
     VerifyBlockResponse,

consensus/src/lib.rs

@@ -24,13 +24,12 @@ use cuprate_consensus_rules::ConsensusError;
 
 mod batch_verifier;
 pub mod block;
-pub mod context;
 #[cfg(test)]
 mod tests;
 pub mod transactions;
 
 pub use block::{BlockVerifierService, VerifyBlockRequest, VerifyBlockResponse};
-pub use context::{
+pub use cuprate_consensus_context::{
     initialize_blockchain_context, BlockChainContext, BlockChainContextRequest,
     BlockChainContextResponse, BlockChainContextService, ContextConfig,
 };

consensus/src/tests/context.rs

@@ -2,15 +2,13 @@ use proptest::strategy::ValueTree;
 use proptest::{strategy::Strategy, test_runner::TestRunner};
 use tower::ServiceExt;
 
-use crate::{
-    context::{
+use cuprate_consensus_context::{
     initialize_blockchain_context, BlockChainContextRequest, BlockChainContextResponse,
     ContextConfig, NewBlockData,
-    },
-    tests::mock_db::*,
-    HardFork,
 };
 
+use crate::{tests::mock_db::*, HardFork};
+
 pub(crate) mod data;
 mod difficulty;
 mod hardforks;

consensus/src/tests/context/difficulty.rs

@@ -4,10 +4,10 @@ use proptest::collection::{size_range, vec};
 use proptest::{prelude::*, prop_assert_eq, prop_compose, proptest};
 
 use crate::{
-    context::difficulty::*,
     tests::{context::data::DIF_3000000_3002000, mock_db::*},
     HardFork,
 };
+use cuprate_consensus_context::difficulty::*;
 use cuprate_helper::num::median;
 use cuprate_types::Chain;
 

consensus/src/tests/context/hardforks.rs

@@ -1,13 +1,11 @@
 use proptest::{collection::vec, prelude::*};
 
+use cuprate_consensus_context::{hardforks::HardForkState, HardForkConfig};
 use cuprate_consensus_rules::hard_forks::{HFInfo, HFsInfo, HardFork, NUMB_OF_HARD_FORKS};
 
-use crate::{
-    context::{hardforks::HardForkState, HardForkConfig},
-    tests::{
+use crate::tests::{
     context::data::{HFS_2678808_2688888, HFS_2688888_2689608},
     mock_db::*,
-    },
 };
 
 const TEST_WINDOW_SIZE: usize = 25;

consensus/src/tests/context/rx_vms.rs

@@ -3,15 +3,13 @@ use std::collections::VecDeque;
 use proptest::prelude::*;
 use tokio::runtime::Builder;
 
+use cuprate_consensus_context::rx_vms::{get_last_rx_seed_heights, RandomXVmCache};
 use cuprate_consensus_rules::{
     blocks::{is_randomx_seed_height, randomx_seed_height},
     HardFork,
 };
 
-use crate::{
-    context::rx_vms::{get_last_rx_seed_heights, RandomXVmCache},
-    tests::mock_db::*,
-};
+use crate::tests::mock_db::*;
 
 #[test]
 fn rx_heights_consistent() {

consensus/src/tests/context/weight.rs

@@ -1,11 +1,11 @@
 use crate::{
-    context::{
-        weight::{calculate_block_long_term_weight, BlockWeightsCache},
-        BlockWeightsCacheConfig,
-    },
     tests::{context::data::BW_2850000_3050000, mock_db::*},
     HardFork,
 };
+use cuprate_consensus_context::{
+    weight::{calculate_block_long_term_weight, BlockWeightsCache},
+    BlockWeightsCacheConfig,
+};
 use cuprate_types::Chain;
 
 pub(crate) const TEST_WEIGHT_CONFIG: BlockWeightsCacheConfig =