lighthouse/beacon_node/eth1/src/block_cache.rs
Paul Hauner 7afbaa807e Return eth1-related data via the API (#1797)
## Issue Addressed

- Related to #1691

## Proposed Changes

Adds the following API endpoints:

- `GET lighthouse/eth1/syncing`: status about how synced we are with Eth1.
- `GET lighthouse/eth1/block_cache`: all locally cached eth1 blocks.
- `GET lighthouse/eth1/deposit_cache`: all locally cached eth1 deposits.

Additionally:

- Moves some types from the `beacon_node/eth1` to the `common/eth2` crate, so they can be used in the API without duplication.
- Allow `update_deposit_cache` and `update_block_cache` to take an optional head block number to avoid duplicate requests.

## Additional Info

TBC
2020-11-02 00:37:30 +00:00

275 lines
9.0 KiB
Rust

use ssz_derive::{Decode, Encode};
use std::ops::RangeInclusive;
pub use eth2::lighthouse::Eth1Block;
#[derive(Debug, PartialEq, Clone)]
pub enum Error {
/// The timestamp of each block equal to or later than the block prior to it.
InconsistentTimestamp { parent: u64, child: u64 },
/// Some `Eth1Block` was provided with the same block number but different data. The source
/// of eth1 data is inconsistent.
Conflicting(u64),
/// The given block was not one block number higher than the higest known block number.
NonConsecutive { given: u64, expected: u64 },
/// Some invariant was violated, there is a likely bug in the code.
Internal(String),
}
/// Stores block and deposit contract information and provides queries based upon the block
/// timestamp.
#[derive(Debug, PartialEq, Clone, Default, Encode, Decode)]
pub struct BlockCache {
blocks: Vec<Eth1Block>,
}
impl BlockCache {
/// Returns the number of blocks stored in `self`.
pub fn len(&self) -> usize {
self.blocks.len()
}
/// True if the cache does not store any blocks.
pub fn is_empty(&self) -> bool {
self.blocks.is_empty()
}
/// Returns the earliest (lowest timestamp) block, if any.
pub fn earliest_block(&self) -> Option<&Eth1Block> {
self.blocks.first()
}
/// Returns the latest (highest timestamp) block, if any.
pub fn latest_block(&self) -> Option<&Eth1Block> {
self.blocks.last()
}
/// Returns the timestamp of the earliest block in the cache (if any).
pub fn earliest_block_timestamp(&self) -> Option<u64> {
self.blocks.first().map(|block| block.timestamp)
}
/// Returns the timestamp of the latest block in the cache (if any).
pub fn latest_block_timestamp(&self) -> Option<u64> {
self.blocks.last().map(|block| block.timestamp)
}
/// Returns the lowest block number stored.
pub fn lowest_block_number(&self) -> Option<u64> {
self.blocks.first().map(|block| block.number)
}
/// Returns the highest block number stored.
pub fn highest_block_number(&self) -> Option<u64> {
self.blocks.last().map(|block| block.number)
}
/// Returns an iterator over all blocks.
///
/// Blocks a guaranteed to be returned with;
///
/// - Monotonically increasing block numbers.
/// - Non-uniformly increasing block timestamps.
pub fn iter(&self) -> impl DoubleEndedIterator<Item = &Eth1Block> + Clone {
self.blocks.iter()
}
/// Shortens the cache, keeping the latest (by block number) `len` blocks while dropping the
/// rest.
///
/// If `len` is greater than the vector's current length, this has no effect.
pub fn truncate(&mut self, len: usize) {
if len < self.blocks.len() {
self.blocks = self.blocks.split_off(self.blocks.len() - len);
}
}
/// Returns the range of block numbers stored in the block cache. All blocks in this range can
/// be accessed.
fn available_block_numbers(&self) -> Option<RangeInclusive<u64>> {
Some(self.blocks.first()?.number..=self.blocks.last()?.number)
}
/// Returns a block with the corresponding number, if any.
pub fn block_by_number(&self, block_number: u64) -> Option<&Eth1Block> {
self.blocks.get(
self.blocks
.as_slice()
.binary_search_by(|block| block.number.cmp(&block_number))
.ok()?,
)
}
/// Insert an `Eth1Snapshot` into `self`, allowing future queries.
///
/// Allows inserting either:
///
/// - The root block (i.e., any block if there are no existing blocks), or,
/// - An immediate child of the most recent (highest block number) block.
///
/// ## Errors
///
/// - If the cache is not empty and `item.block.block_number - 1` is not already in `self`.
/// - If `item.block.block_number` is in `self`, but is not identical to the supplied
/// `Eth1Snapshot`.
/// - If `item.block.timestamp` is prior to the parent.
pub fn insert_root_or_child(&mut self, block: Eth1Block) -> Result<(), Error> {
let expected_block_number = self
.highest_block_number()
.map(|n| n + 1)
.unwrap_or_else(|| block.number);
// If there are already some cached blocks, check to see if the new block number is one of
// them.
//
// If the block is already known, check to see the given block is identical to it. If not,
// raise an inconsistency error. This is mostly likely caused by some fork on the eth1
// chain.
if let Some(local) = self.available_block_numbers() {
if local.contains(&block.number) {
let known_block = self.block_by_number(block.number).ok_or_else(|| {
Error::Internal("An expected block was not present".to_string())
})?;
if known_block == &block {
return Ok(());
} else {
return Err(Error::Conflicting(block.number));
};
}
}
// Only permit blocks when it's either:
//
// - The first block inserted.
// - Exactly one block number higher than the highest known block number.
if block.number != expected_block_number {
return Err(Error::NonConsecutive {
given: block.number,
expected: expected_block_number,
});
}
// If the block is not the first block inserted, ensure that its timestamp is not higher
// than its parents.
if let Some(previous_block) = self.blocks.last() {
if previous_block.timestamp > block.timestamp {
return Err(Error::InconsistentTimestamp {
parent: previous_block.timestamp,
child: block.timestamp,
});
}
}
self.blocks.push(block);
Ok(())
}
}
#[cfg(test)]
mod tests {
use super::*;
use types::Hash256;
fn get_block(i: u64, interval_secs: u64) -> Eth1Block {
Eth1Block {
hash: Hash256::from_low_u64_be(i),
timestamp: i * interval_secs,
number: i,
deposit_root: Some(Hash256::from_low_u64_be(i << 32)),
deposit_count: Some(i),
}
}
fn get_blocks(n: usize, interval_secs: u64) -> Vec<Eth1Block> {
(0..n as u64).map(|i| get_block(i, interval_secs)).collect()
}
fn insert(cache: &mut BlockCache, s: Eth1Block) -> Result<(), Error> {
cache.insert_root_or_child(s)
}
#[test]
fn truncate() {
let n = 16;
let blocks = get_blocks(n, 10);
let mut cache = BlockCache::default();
for block in blocks {
insert(&mut cache, block.clone()).expect("should add consecutive blocks");
}
for len in &[0, 1, 2, 3, 4, 8, 15, 16] {
let mut cache = cache.clone();
cache.truncate(*len);
assert_eq!(
cache.blocks.len(),
*len,
"should truncate to length: {}",
*len
);
}
let mut cache_2 = cache;
cache_2.truncate(17);
assert_eq!(
cache_2.blocks.len(),
n,
"truncate to larger than n should be a no-op"
);
}
#[test]
fn inserts() {
let n = 16;
let blocks = get_blocks(n, 10);
let mut cache = BlockCache::default();
for block in blocks {
insert(&mut cache, block.clone()).expect("should add consecutive blocks");
}
// No error for re-adding a block identical to one that exists.
assert!(insert(&mut cache, get_block(n as u64 - 1, 10)).is_ok());
// Error for re-adding a block that is different to the one that exists.
assert!(insert(&mut cache, get_block(n as u64 - 1, 11)).is_err());
// Error for adding non-consecutive blocks.
assert!(insert(&mut cache, get_block(n as u64 + 1, 10)).is_err());
assert!(insert(&mut cache, get_block(n as u64 + 2, 10)).is_err());
// Error for adding timestamp prior to previous.
assert!(insert(&mut cache, get_block(n as u64, 1)).is_err());
// Double check to make sure previous test was only affected by timestamp.
assert!(insert(&mut cache, get_block(n as u64, 10)).is_ok());
}
#[test]
fn duplicate_timestamp() {
let mut blocks = get_blocks(7, 10);
blocks[0].timestamp = 0;
blocks[1].timestamp = 10;
blocks[2].timestamp = 10;
blocks[3].timestamp = 20;
blocks[4].timestamp = 30;
blocks[5].timestamp = 40;
blocks[6].timestamp = 40;
let mut cache = BlockCache::default();
for block in &blocks {
insert(&mut cache, block.clone())
.expect("should add consecutive blocks with duplicate timestamps");
}
assert_eq!(cache.blocks, blocks, "should have added all blocks");
}
}