web3-proxy/web3_proxy/src/rpcs/blockchain.rs
2023-03-19 18:52:28 -07:00

604 lines
22 KiB
Rust

///! Keep track of the blockchain as seen by a Web3Rpcs.
use super::consensus::ConsensusFinder;
use super::many::Web3Rpcs;
use super::one::Web3Rpc;
use super::transactions::TxStatus;
use crate::frontend::authorization::Authorization;
use crate::frontend::errors::Web3ProxyResult;
use crate::{config::BlockAndRpc, jsonrpc::JsonRpcRequest};
use anyhow::{anyhow, Context};
use derive_more::From;
use ethers::prelude::{Block, TxHash, H256, U64};
use log::{debug, trace, warn, Level};
use moka::future::Cache;
use serde::ser::SerializeStruct;
use serde::Serialize;
use serde_json::json;
use std::{cmp::Ordering, fmt::Display, sync::Arc};
use tokio::sync::broadcast;
use tokio::time::Duration;
// TODO: type for Hydrated Blocks with their full transactions?
pub type ArcBlock = Arc<Block<TxHash>>;
pub type BlocksByHashCache = Cache<H256, Web3ProxyBlock, hashbrown::hash_map::DefaultHashBuilder>;
/// A block and its age.
#[derive(Clone, Debug, Default, From)]
pub struct Web3ProxyBlock {
pub block: ArcBlock,
/// number of seconds this block was behind the current time when received
/// this is only set if the block is from a subscription
pub received_age: Option<u64>,
}
impl Serialize for Web3ProxyBlock {
fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
where
S: serde::Serializer,
{
// TODO: i'm not sure about this name
let mut state = serializer.serialize_struct("saved_block", 2)?;
state.serialize_field("age", &self.age())?;
let block = json!({
"block_hash": self.block.hash,
"parent_hash": self.block.parent_hash,
"number": self.block.number,
"timestamp": self.block.timestamp,
});
state.serialize_field("block", &block)?;
state.end()
}
}
impl PartialEq for Web3ProxyBlock {
fn eq(&self, other: &Self) -> bool {
match (self.block.hash, other.block.hash) {
(None, None) => true,
(Some(_), None) => false,
(None, Some(_)) => false,
(Some(s), Some(o)) => s == o,
}
}
}
impl Web3ProxyBlock {
/// A new block has arrived over a subscription
pub fn try_new(block: ArcBlock) -> Option<Self> {
if block.number.is_none() || block.hash.is_none() {
return None;
}
let mut x = Self {
block,
received_age: None,
};
// no need to recalulate lag every time
// if the head block gets too old, a health check restarts this connection
// TODO: emit a stat for received_age
x.received_age = Some(x.age());
Some(x)
}
pub fn age(&self) -> u64 {
let now = chrono::Utc::now().timestamp();
let block_timestamp = self.block.timestamp.as_u32() as i64;
if block_timestamp < now {
// this server is still syncing from too far away to serve requests
// u64 is safe because ew checked equality above
// (now - block_timestamp).as_secs()
// u64 is safe because we checked equality above
(now - block_timestamp) as u64
} else {
0
}
}
#[inline(always)]
pub fn parent_hash(&self) -> &H256 {
&self.block.parent_hash
}
#[inline(always)]
pub fn hash(&self) -> &H256 {
self.block
.hash
.as_ref()
.expect("saved blocks must have a hash")
}
#[inline(always)]
pub fn number(&self) -> &U64 {
self.block
.number
.as_ref()
.expect("saved blocks must have a number")
}
}
impl TryFrom<ArcBlock> for Web3ProxyBlock {
type Error = anyhow::Error;
fn try_from(x: ArcBlock) -> Result<Self, Self::Error> {
if x.number.is_none() || x.hash.is_none() {
return Err(anyhow!("Blocks here must have a number of hash"));
}
let b = Web3ProxyBlock {
block: x,
received_age: None,
};
Ok(b)
}
}
impl Display for Web3ProxyBlock {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
write!(
f,
"{} ({}, {}s old)",
self.number(),
self.hash(),
self.age()
)
}
}
impl Web3Rpcs {
/// add a block to our mappings and track the heaviest chain
pub async fn try_cache_block(
&self,
block: Web3ProxyBlock,
heaviest_chain: bool,
) -> Web3ProxyResult<Web3ProxyBlock> {
// TODO: i think we can rearrange this function to make it faster on the hot path
let block_hash = block.hash();
// skip Block::default()
if block_hash.is_zero() {
debug!("Skipping block without hash!");
return Ok(block);
}
let block_num = block.number();
// TODO: think more about heaviest_chain. would be better to do the check inside this function
if heaviest_chain {
// this is the only place that writes to block_numbers
// multiple inserts should be okay though
// TODO: info that there was a fork?
self.blocks_by_number.insert(*block_num, *block_hash).await;
}
// this block is very likely already in block_hashes
// TODO: use their get_with
let block = self
.blocks_by_hash
.get_with(*block_hash, async move { block.clone() })
.await;
Ok(block)
}
/// Get a block from caches with fallback.
/// Will query a specific node or the best available.
/// TODO: return anyhow::Result<Option<ArcBlock>>?
pub async fn block(
&self,
authorization: &Arc<Authorization>,
hash: &H256,
rpc: Option<&Arc<Web3Rpc>>,
) -> Web3ProxyResult<Web3ProxyBlock> {
// first, try to get the hash from our cache
// the cache is set last, so if its here, its everywhere
// TODO: use try_get_with
if let Some(block) = self.blocks_by_hash.get(hash) {
return Ok(block);
}
// block not in cache. we need to ask an rpc for it
let get_block_params = (*hash, false);
// TODO: if error, retry?
let block: Web3ProxyBlock = match rpc {
Some(rpc) => rpc
.wait_for_request_handle(authorization, Some(Duration::from_secs(30)), None)
.await?
.request::<_, Option<ArcBlock>>(
"eth_getBlockByHash",
&json!(get_block_params),
Level::Error.into(),
None,
)
.await?
.and_then(|x| {
if x.number.is_none() {
None
} else {
x.try_into().ok()
}
})
.context("no block!")?,
None => {
// TODO: helper for method+params => JsonRpcRequest
// TODO: does this id matter?
let request = json!({ "id": "1", "method": "eth_getBlockByHash", "params": get_block_params });
let request: JsonRpcRequest = serde_json::from_value(request)?;
// TODO: request_metadata? maybe we should put it in the authorization?
// TODO: think more about this wait_for_sync
let response = self
.try_send_best_consensus_head_connection(
authorization,
request,
None,
None,
None,
)
.await?;
let block = response.result.context("failed fetching block")?;
let block: Option<ArcBlock> = serde_json::from_str(block.get())?;
let block: ArcBlock = block.context("no block in the response")?;
// TODO: received time is going to be weird
Web3ProxyBlock::try_from(block)?
}
};
// the block was fetched using eth_getBlockByHash, so it should have all fields
// TODO: fill in heaviest_chain! if the block is old enough, is this definitely true?
let block = self.try_cache_block(block, false).await?;
Ok(block)
}
/// Convenience method to get the cannonical block at a given block height.
pub async fn block_hash(
&self,
authorization: &Arc<Authorization>,
num: &U64,
) -> Web3ProxyResult<(H256, u64)> {
let (block, block_depth) = self.cannonical_block(authorization, num).await?;
let hash = *block.hash();
Ok((hash, block_depth))
}
/// Get the heaviest chain's block from cache or backend rpc
/// Caution! If a future block is requested, this might wait forever. Be sure to have a timeout outside of this!
pub async fn cannonical_block(
&self,
authorization: &Arc<Authorization>,
num: &U64,
) -> Web3ProxyResult<(Web3ProxyBlock, u64)> {
// we only have blocks by hash now
// maybe save them during save_block in a blocks_by_number Cache<U64, Vec<ArcBlock>>
// if theres multiple, use petgraph to find the one on the main chain (and remove the others if they have enough confirmations)
let mut consensus_head_receiver = self
.watch_consensus_head_sender
.as_ref()
.context("need new head subscriptions to fetch cannonical_block")?
.subscribe();
// be sure the requested block num exists
// TODO: is this okay? what if we aren't synced?!
let mut head_block_num = *consensus_head_receiver
.borrow_and_update()
.as_ref()
.context("no consensus head block")?
.number();
loop {
if num <= &head_block_num {
break;
}
trace!("waiting for future block {} > {}", num, head_block_num);
consensus_head_receiver.changed().await?;
if let Some(head) = consensus_head_receiver.borrow_and_update().as_ref() {
head_block_num = *head.number();
}
}
let block_depth = (head_block_num - num).as_u64();
// try to get the hash from our cache
// deref to not keep the lock open
if let Some(block_hash) = self.blocks_by_number.get(num) {
// TODO: sometimes this needs to fetch the block. why? i thought block_numbers would only be set if the block hash was set
// TODO: pass authorization through here?
let block = self.block(authorization, &block_hash, None).await?;
return Ok((block, block_depth));
}
// block number not in cache. we need to ask an rpc for it
// TODO: helper for method+params => JsonRpcRequest
let request = json!({ "jsonrpc": "2.0", "id": "1", "method": "eth_getBlockByNumber", "params": (num, false) });
let request: JsonRpcRequest = serde_json::from_value(request)?;
// TODO: if error, retry?
// TODO: request_metadata or authorization?
// we don't actually set min_block_needed here because all nodes have all blocks
let response = self
.try_send_best_consensus_head_connection(authorization, request, None, Some(num), None)
.await?;
if let Some(err) = response.error {
debug!("could not find canonical block {}: {:?}", num, err);
}
let raw_block = response.result.context("no cannonical block result")?;
let block: ArcBlock = serde_json::from_str(raw_block.get())?;
let block = Web3ProxyBlock::try_from(block)?;
// the block was fetched using eth_getBlockByNumber, so it should have all fields and be on the heaviest chain
let block = self.try_cache_block(block, true).await?;
Ok((block, block_depth))
}
pub(super) async fn process_incoming_blocks(
&self,
authorization: &Arc<Authorization>,
block_receiver: flume::Receiver<BlockAndRpc>,
// TODO: document that this is a watch sender and not a broadcast! if things get busy, blocks might get missed
// Geth's subscriptions have the same potential for skipping blocks.
pending_tx_sender: Option<broadcast::Sender<TxStatus>>,
) -> anyhow::Result<()> {
let mut connection_heads = ConsensusFinder::new(self.max_block_age, self.max_block_lag);
loop {
match block_receiver.recv_async().await {
Ok((new_block, rpc)) => {
let rpc_name = rpc.name.clone();
if let Err(err) = self
.process_block_from_rpc(
authorization,
&mut connection_heads,
new_block,
rpc,
&pending_tx_sender,
)
.await
{
warn!("unable to process block from rpc {}: {:#?}", rpc_name, err);
}
}
Err(err) => {
warn!("block_receiver exited! {:#?}", err);
return Err(err.into());
}
}
}
}
/// `connection_heads` is a mapping of rpc_names to head block hashes.
/// self.blockchain_map is a mapping of hashes to the complete ArcBlock.
/// TODO: return something?
pub(crate) async fn process_block_from_rpc(
&self,
authorization: &Arc<Authorization>,
consensus_finder: &mut ConsensusFinder,
new_block: Option<Web3ProxyBlock>,
rpc: Arc<Web3Rpc>,
_pending_tx_sender: &Option<broadcast::Sender<TxStatus>>,
) -> anyhow::Result<()> {
// TODO: how should we handle an error here?
if !consensus_finder
.update_rpc(new_block.clone(), rpc.clone(), self)
.await
.context("failed to update rpc")?
{
// nothing changed. no need to scan for a new consensus head
return Ok(());
}
let new_consensus = consensus_finder
.best_consensus_connections(authorization, self)
.await
.context("no consensus head block!")
.map_err(|err| {
self.watch_consensus_rpcs_sender.send_replace(None);
err
})?;
// TODO: what should we do if the block number of new_consensus is < old_synced_connections? wait?
let watch_consensus_head_sender = self.watch_consensus_head_sender.as_ref().unwrap();
let consensus_tier = new_consensus.tier;
let total_tiers = consensus_finder.len();
let backups_needed = new_consensus.backups_needed;
let consensus_head_block = new_consensus.head_block.clone();
let num_consensus_rpcs = new_consensus.num_conns();
let mut num_synced_rpcs = 0;
let num_active_rpcs = consensus_finder
.all_rpcs_group()
.map(|x| {
for v in x.rpc_to_block.values() {
if *v == consensus_head_block {
num_synced_rpcs += 1;
}
}
x.len()
})
.unwrap_or_default();
let total_rpcs = self.by_name.read().len();
let old_consensus_head_connections = self
.watch_consensus_rpcs_sender
.send_replace(Some(Arc::new(new_consensus)));
let backups_voted_str = if backups_needed { "B " } else { "" };
match old_consensus_head_connections.as_ref() {
None => {
debug!(
"first {}/{} {}{}/{}/{} block={}, rpc={}",
consensus_tier,
total_tiers,
backups_voted_str,
num_consensus_rpcs,
num_active_rpcs,
total_rpcs,
consensus_head_block,
rpc,
);
if backups_needed {
// TODO: what else should be in this error?
warn!("Backup RPCs are in use!");
}
// this should already be cached
let consensus_head_block = self.try_cache_block(consensus_head_block, true).await?;
watch_consensus_head_sender
.send(Some(consensus_head_block))
.context(
"watch_consensus_head_sender failed sending first consensus_head_block",
)?;
}
Some(old_consensus_connections) => {
let old_head_block = &old_consensus_connections.head_block;
// TODO: do this log item better
let rpc_head_str = new_block
.map(|x| x.to_string())
.unwrap_or_else(|| "None".to_string());
match consensus_head_block.number().cmp(old_head_block.number()) {
Ordering::Equal => {
// multiple blocks with the same fork!
if consensus_head_block.hash() == old_head_block.hash() {
// no change in hash. no need to use watch_consensus_head_sender
// TODO: trace level if rpc is backup
debug!(
"con {}/{} {}{}/{}/{}/{} con={} rpc={}@{}",
consensus_tier,
total_tiers,
backups_voted_str,
num_consensus_rpcs,
num_synced_rpcs,
num_active_rpcs,
total_rpcs,
consensus_head_block,
rpc,
rpc_head_str,
)
} else {
// hash changed
if backups_needed {
// TODO: what else should be in this error?
warn!("Backup RPCs are in use!");
}
debug!(
"unc {}/{} {}{}/{}/{}/{} con_head={} old={} rpc={}@{}",
consensus_tier,
total_tiers,
backups_voted_str,
num_consensus_rpcs,
num_synced_rpcs,
num_active_rpcs,
total_rpcs,
consensus_head_block,
old_head_block,
rpc,
rpc_head_str,
);
let consensus_head_block = self
.try_cache_block(consensus_head_block, true)
.await
.context("save consensus_head_block as heaviest chain")?;
watch_consensus_head_sender
.send(Some(consensus_head_block))
.context("watch_consensus_head_sender failed sending uncled consensus_head_block")?;
}
}
Ordering::Less => {
// this is unlikely but possible
// TODO: better log
warn!(
"chain rolled back {}/{} {}{}/{}/{}/{} con={} old={} rpc={}@{}",
consensus_tier,
total_tiers,
backups_voted_str,
num_consensus_rpcs,
num_synced_rpcs,
num_active_rpcs,
total_rpcs,
consensus_head_block,
old_head_block,
rpc,
rpc_head_str,
);
if backups_needed {
// TODO: what else should be in this error?
warn!("Backup RPCs are in use!");
}
// TODO: tell save_block to remove any higher block numbers from the cache. not needed because we have other checks on requested blocks being > head, but still seems like a good idea
let consensus_head_block = self
.try_cache_block(consensus_head_block, true)
.await
.context("save_block sending consensus_head_block as heaviest chain")?;
watch_consensus_head_sender
.send(Some(consensus_head_block))
.context("watch_consensus_head_sender failed sending rollback consensus_head_block")?;
}
Ordering::Greater => {
debug!(
"new {}/{} {}{}/{}/{}/{} con={} rpc={}@{}",
consensus_tier,
total_tiers,
backups_voted_str,
num_consensus_rpcs,
num_synced_rpcs,
num_active_rpcs,
total_rpcs,
consensus_head_block,
rpc,
rpc_head_str,
);
if backups_needed {
// TODO: what else should be in this error?
warn!("Backup RPCs are in use!");
}
let consensus_head_block =
self.try_cache_block(consensus_head_block, true).await?;
watch_consensus_head_sender.send(Some(consensus_head_block)).context("watch_consensus_head_sender failed sending new consensus_head_block")?;
}
}
}
}
Ok(())
}
}