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Integrate fork choice into beacon_chain.

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- Adds fork_choice to beacon_chain struct.
- Adds add_attestation inside process_free_attestation.
- Adds add_block inside process_block.
- Shifts core fork-choice logic into lib.rs.
This commit is contained in:
Age Manning 2019-02-12 21:49:24 +11:00
parent fb270a5a41
commit eae68865d1
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GPG Key ID: 05EED64B79E06A93
4 changed files with 107 additions and 91 deletions
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85
beacon_node/beacon_chain/src/beacon_chain.rs
View File

@ -2,6 +2,7 @@ use db::{
stores::{BeaconBlockStore, BeaconStateStore},
ClientDB, DBError,
};
use fork_choice::{ForkChoice, ForkChoiceError};
use genesis::{genesis_beacon_block, genesis_beacon_state};
use log::{debug, trace};
use parking_lot::{RwLock, RwLockReadGuard};
@ -14,11 +15,8 @@ use types::{
AttestationData, BeaconBlock, BeaconBlockBody, BeaconState, ChainSpec, Eth1Data,
FreeAttestation, Hash256, PublicKey, Signature,
};
use fork_choice::{longest_chain, basic_lmd_ghost};
use fork_choice::{ForkChoice};
use crate::attestation_aggregator::{AttestationAggregator, Outcome as AggregationOutcome};
use crate::attestation_targets::AttestationTargets;
use crate::block_graph::BlockGraph;
use crate::checkpoint::CheckPoint;
@ -29,6 +27,9 @@ pub enum Error {
CommitteesError(CommitteesError),
DBInconsistent(String),
DBError(String),
ForkChoiceError(ForkChoiceError),
MissingBeaconBlock(Hash256),
MissingBeaconState(Hash256),
}
#[derive(Debug, PartialEq)]
@ -60,7 +61,7 @@ pub enum BlockProcessingOutcome {
InvalidBlock(InvalidBlock),
}
pub struct BeaconChain<T: ClientDB + Sized, U: SlotClock> {
pub struct BeaconChain<T: ClientDB + Sized, U: SlotClock, F: ForkChoice> {
pub block_store: Arc<BeaconBlockStore<T>>,
pub state_store: Arc<BeaconStateStore<T>>,
pub slot_clock: U,
@ -70,14 +71,15 @@ pub struct BeaconChain<T: ClientDB + Sized, U: SlotClock> {
finalized_head: RwLock<CheckPoint>,
justified_head: RwLock<CheckPoint>,
pub state: RwLock<BeaconState>,
pub latest_attestation_targets: RwLock<AttestationTargets>,
pub spec: ChainSpec,
pub fork_choice: F,
}
impl<T, U> BeaconChain<T, U>
impl<T, U, F> BeaconChain<T, U, F>
where
T: ClientDB,
U: SlotClock,
F: ForkChoice,
{
/// Instantiate a new Beacon Chain, from genesis.
pub fn genesis(
@ -85,6 +87,7 @@ where
block_store: Arc<BeaconBlockStore<T>>,
slot_clock: U,
spec: ChainSpec,
fork_choice: F,
) -> Result<Self, Error> {
if spec.initial_validators.is_empty() {
return Err(Error::InsufficientValidators);
@ -121,8 +124,6 @@ where
));
let attestation_aggregator = RwLock::new(AttestationAggregator::new());
let latest_attestation_targets = RwLock::new(AttestationTargets::new());
Ok(Self {
block_store,
state_store,
@ -133,8 +134,8 @@ where
justified_head,
finalized_head,
canonical_head,
latest_attestation_targets,
spec: spec,
fork_choice,
})
}
@ -209,7 +210,7 @@ where
Ok(())
}
/// Returns the the validator index (if any) for the given public key.
/// Returns the validator index (if any) for the given public key.
///
/// Information is retrieved from the present `beacon_state.validator_registry`.
pub fn validator_index(&self, pubkey: &PublicKey) -> Option<usize> {
@ -338,29 +339,27 @@ where
/// - Create a new `Attestation`.
/// - Aggregate it to an existing `Attestation`.
pub fn process_free_attestation(
&self,
&mut self,
free_attestation: FreeAttestation,
) -> Result<AggregationOutcome, Error> {
self.attestation_aggregator
let aggregation_outcome = self
.attestation_aggregator
.write()
.process_free_attestation(&self.state.read(), &free_attestation, &self.spec)
.map_err(|e| e.into())
}
.process_free_attestation(&self.state.read(), &free_attestation, &self.spec)?;
// TODO: Check this comment
//.map_err(|e| e.into())?;
/// Set the latest attestation target for some validator.
pub fn insert_latest_attestation_target(&self, validator_index: u64, block_root: Hash256) {
let mut targets = self.latest_attestation_targets.write();
targets.insert(validator_index, block_root);
}
/// Get the latest attestation target for some validator.
pub fn get_latest_attestation_target(&self, validator_index: u64) -> Option<Hash256> {
let targets = self.latest_attestation_targets.read();
match targets.get(validator_index) {
Some(hash) => Some(hash.clone()),
None => None,
// return if the attestation is invalid
if !aggregation_outcome.valid {
return Ok(aggregation_outcome);
}
// valid attestation, proceed with fork-choice logic
self.fork_choice.add_attestation(
free_attestation.validator_index,
&free_attestation.data.beacon_block_root,
)?;
Ok(aggregation_outcome)
}
/// Dumps the entire canonical chain, from the head to genesis to a vector for analysis.
@ -417,7 +416,7 @@ where
/// Accept some block and attempt to add it to block DAG.
///
/// Will accept blocks from prior slots, however it will reject any block from a future slot.
pub fn process_block(&self, block: BeaconBlock) -> Result<BlockProcessingOutcome, Error> {
pub fn process_block(&mut self, block: BeaconBlock) -> Result<BlockProcessingOutcome, Error> {
debug!("Processing block with slot {}...", block.slot());
let block_root = block.canonical_root();
@ -471,7 +470,7 @@ where
}
}
// Apply the recieved block to its parent state (which has been transitioned into this
// Apply the received block to its parent state (which has been transitioned into this
// slot).
if let Err(e) = state.per_block_processing(&block, &self.spec) {
return Ok(BlockProcessingOutcome::InvalidBlock(
@ -495,6 +494,9 @@ where
self.block_graph
.add_leaf(&parent_block_root, block_root.clone());
// run the fork_choice add_block logic
self.fork_choice.add_block(&block, &block_root)?;
// If the parent block was the parent_block, automatically update the canonical head.
//
// TODO: this is a first-in-best-dressed scenario that is not ideal; fork_choice should be
@ -574,15 +576,11 @@ where
Some((block, state))
}
// For now, we give it the option of choosing which fork choice to use
pub fn fork_choice(&self, fork_choice: ForkChoice) -> Result<(), Error> {
let present_head = &self.finalized_head().beacon_block_root;
// TODO: Left this as is, modify later
pub fn fork_choice(&mut self) -> Result<(), Error> {
let present_head = &self.finalized_head().beacon_block_root.clone();
let new_head = match fork_choice {
ForkChoice::BasicLMDGhost => basic_lmd_ghost(&self.finalized_head().beacon_block_root)?,
// TODO: Implement others
_ => present_head
}
let new_head = self.fork_choice.find_head(present_head)?;
if new_head != *present_head {
let block = self
@ -601,18 +599,21 @@ where
}
Ok(())
}
}
impl From<DBError> for Error {
fn from(e: DBError) -> Error {
Error::DBError(e.message)
}
}
impl From<ForkChoiceError> for Error {
fn from(e: ForkChoiceError) -> Error {
Error::ForkChoiceError(e)
}
}
impl From<CommitteesError> for Error {
fn from(e: CommitteesError) -> Error {
Error::CommitteesError(e)

1
beacon_node/beacon_chain/src/lib.rs
View File

@ -1,5 +1,4 @@
mod attestation_aggregator;
mod attestation_targets;
mod beacon_chain;
mod block_graph;
mod checkpoint;

45
eth2/fork_choice/src/lib.rs
View File

@ -23,8 +23,51 @@ pub mod longest_chain;
pub mod optimised_lmd_ghost;
pub mod protolambda_lmd_ghost;
use db::DBError;
use types::{BeaconBlock, Hash256};
/// Defines the interface for Fork Choices. Each Fork choice will define their own data structures
/// which can be built in block processing through the `add_block` and `add_attestation` functions.
/// The main fork choice algorithm is specified in `find_head`.
pub trait ForkChoice {
/// Called when a block has been added. Allows generic block-level data structures to be
/// built for a given fork-choice.
fn add_block(
&mut self,
block: &BeaconBlock,
block_hash: &Hash256,
) -> Result<(), ForkChoiceError>;
/// Called when an attestation has been added. Allows generic attestation-level data structures to be built for a given fork choice.
// This can be generalised to a full attestation if required later.
fn add_attestation(
&mut self,
validator_index: u64,
target_block_hash: &Hash256,
) -> Result<(), ForkChoiceError>;
/// The fork-choice algorithm to find the current canonical head of the chain.
// TODO: Remove the justified_start_block parameter and make it internal
fn find_head(&mut self, justified_start_block: &Hash256) -> Result<Hash256, ForkChoiceError>;
}
/// Possible fork choice errors that can occur.
#[derive(Debug, PartialEq)]
pub enum ForkChoiceError {
MissingBeaconBlock(Hash256),
MissingBeaconState(Hash256),
IncorrectBeaconState(Hash256),
CannotFindBestChild,
ChildrenNotFound,
StorageError(String),
}
impl From<DBError> for ForkChoiceError {
fn from(e: DBError) -> ForkChoiceError {
ForkChoiceError::StorageError(e.message)
}
}
/// Fork choice options that are currently implemented.
pub enum ForkChoice {
pub enum ForkChoiceAlgorithms {
/// Chooses the longest chain becomes the head. Not for production.
LongestChain,
/// A simple and highly inefficient implementation of LMD ghost.

67
eth2/fork_choice/src/optimised_lmd_ghost.rs
View File

@ -1,9 +1,10 @@
extern crate byteorder;
extern crate fast_math;
use crate::{ForkChoice, ForkChoiceError};
use byteorder::{BigEndian, ByteOrder};
use db::{
stores::{BeaconBlockStore, BeaconStateStore},
ClientDB, DBError,
ClientDB,
};
use fast_math::log2_raw;
use std::collections::HashMap;
@ -11,7 +12,7 @@ use std::sync::Arc;
use types::{
readers::{BeaconBlockReader, BeaconStateReader},
validator_registry::get_active_validator_indices,
Attestation, BeaconBlock, Hash256,
BeaconBlock, Hash256,
};
//TODO: Sort out global constants
@ -46,7 +47,7 @@ pub struct OptimisedLMDGhost<T: ClientDB + Sized> {
children: HashMap<Hash256, Vec<Hash256>>,
/// The latest attestation targets as a map of validator index to block hash.
//TODO: Could this be a fixed size vec
latest_attestation_targets: HashMap<usize, Hash256>,
latest_attestation_targets: HashMap<u64, Hash256>,
/// Block storage access.
block_store: Arc<BeaconBlockStore<T>>,
/// State storage access.
@ -82,7 +83,7 @@ where
.into_beacon_block()?
.slot;
(block_slot - self.GENESIS_SLOT) as u32
(block_slot - GENESIS_SLOT) as u32
};
// verify we haven't exceeded the block height
@ -202,7 +203,7 @@ impl<T: ClientDB + Sized> ForkChoice for OptimisedLMDGhost<T> {
.get_reader(&block.parent_root)?
.ok_or_else(|| ForkChoiceError::MissingBeaconBlock(block.parent_root))?
.slot()
- self.GENESIS_SLOT;
- GENESIS_SLOT;
let parent_hash = &block.parent_root;
@ -228,8 +229,14 @@ impl<T: ClientDB + Sized> ForkChoice for OptimisedLMDGhost<T> {
Ok(())
}
fn add_attestation(&mut self, attestation: &Attestation) -> Result<(), ForkChoiceError> {
// simply add the attestation to the latest_message_target mapping
fn add_attestation(
&mut self,
validator_index: u64,
target_block_root: &Hash256,
) -> Result<(), ForkChoiceError> {
// simply add the attestation to the latest_attestation_target
self.latest_attestation_targets
.insert(validator_index, target_block_root.clone());
Ok(())
}
@ -242,7 +249,7 @@ impl<T: ClientDB + Sized> ForkChoice for OptimisedLMDGhost<T> {
//.into_beacon_block()?;
let block_slot = block.slot();
let block_height = block_slot - self.GENESIS_SLOT;
let block_height = block_slot - GENESIS_SLOT;
let state_root = block.state_root();
// get latest votes
@ -262,12 +269,12 @@ impl<T: ClientDB + Sized> ForkChoice for OptimisedLMDGhost<T> {
let active_validator_indices =
get_active_validator_indices(&current_state.validator_registry, block_slot);
for i in active_validator_indices {
for index in active_validator_indices {
let balance =
std::cmp::min(current_state.validator_balances[i], self.MAX_DEPOSIT_AMOUNT)
/ self.FORK_CHOICE_BALANCE_INCREMENT;
std::cmp::min(current_state.validator_balances[index], MAX_DEPOSIT_AMOUNT)
/ FORK_CHOICE_BALANCE_INCREMENT;
if balance > 0 {
if let Some(target) = self.latest_attestation_targets.get(&(i as usize)) {
if let Some(target) = self.latest_attestation_targets.get(&(index as u64)) {
*latest_votes.entry(*target).or_insert_with(|| 0) += balance;
}
}
@ -331,7 +338,7 @@ impl<T: ClientDB + Sized> ForkChoice for OptimisedLMDGhost<T> {
.get_reader(&current_head)?
.ok_or_else(|| ForkChoiceError::MissingBeaconBlock(*justified_block_start))?
.slot()
- self.GENESIS_SLOT;
- GENESIS_SLOT;
// prune the latest votes for votes that are not part of current chosen chain
// more specifically, only keep votes that have head as an ancestor
@ -342,40 +349,6 @@ impl<T: ClientDB + Sized> ForkChoice for OptimisedLMDGhost<T> {
}
}
/// Defines the interface for Fork Choices. Each Fork choice will define their own data structures
/// which can be built in block processing through the `add_block` and `add_attestation` functions.
/// The main fork choice algorithm is specified in `find_head`.
pub trait ForkChoice {
/// Called when a block has been added. Allows generic block-level data structures to be
/// built for a given fork-choice.
fn add_block(
&mut self,
block: &BeaconBlock,
block_hash: &Hash256,
) -> Result<(), ForkChoiceError>;
/// Called when an attestation has been added. Allows generic attestation-level data structures to be built for a given fork choice.
fn add_attestation(&mut self, attestation: &Attestation) -> Result<(), ForkChoiceError>;
/// The fork-choice algorithm to find the current canonical head of the chain.
// TODO: Remove the justified_start_block parameter and make it internal
fn find_head(&mut self, justified_start_block: &Hash256) -> Result<Hash256, ForkChoiceError>;
}
/// Possible fork choice errors that can occur.
pub enum ForkChoiceError {
MissingBeaconBlock(Hash256),
MissingBeaconState(Hash256),
IncorrectBeaconState(Hash256),
CannotFindBestChild,
ChildrenNotFound,
StorageError(String),
}
impl From<DBError> for ForkChoiceError {
fn from(e: DBError) -> ForkChoiceError {
ForkChoiceError::StorageError(e.message)
}
}
/// Type for storing blocks in a memory cache. Key is comprised of block-hash plus the height.
#[derive(PartialEq, Eq, Hash)]
pub struct CacheKey<T> {