web3-proxy/web3_proxy/src/rpcs/connections.rs
2022-09-24 07:04:11 +00:00

688 lines
27 KiB
Rust

///! Load balanced communication with a group of web3 providers
use super::blockchain::{ArcBlock, BlockHashesCache};
use super::connection::Web3Connection;
use super::request::{
OpenRequestHandle, OpenRequestHandleMetrics, OpenRequestResult, RequestErrorHandler,
};
use super::synced_connections::SyncedConnections;
use crate::app::{flatten_handle, AnyhowJoinHandle};
use crate::config::{BlockAndRpc, TxHashAndRpc, Web3ConnectionConfig};
use crate::frontend::authorization::AuthorizedRequest;
use crate::jsonrpc::{JsonRpcForwardedResponse, JsonRpcRequest};
use crate::rpcs::transactions::TxStatus;
use arc_swap::ArcSwap;
use counter::Counter;
use derive_more::From;
use ethers::prelude::{ProviderError, TxHash, H256, U64};
use futures::future::{join_all, try_join_all};
use futures::stream::FuturesUnordered;
use futures::StreamExt;
use hashbrown::HashMap;
use moka::future::{Cache, ConcurrentCacheExt};
use petgraph::graphmap::DiGraphMap;
use serde::ser::{SerializeStruct, Serializer};
use serde::Serialize;
use serde_json::json;
use serde_json::value::RawValue;
use std::cmp;
use std::cmp::Reverse;
use std::fmt;
use std::sync::Arc;
use tokio::sync::RwLock as AsyncRwLock;
use tokio::sync::{broadcast, watch};
use tokio::task;
use tokio::time::{interval, sleep, sleep_until, Duration, Instant, MissedTickBehavior};
use tracing::{error, info, instrument, trace, warn};
/// A collection of web3 connections. Sends requests either the current best server or all servers.
#[derive(From)]
pub struct Web3Connections {
pub(super) conns: HashMap<String, Arc<Web3Connection>>,
/// any requests will be forwarded to one (or more) of these connections
pub(super) synced_connections: ArcSwap<SyncedConnections>,
pub(super) pending_transactions:
Cache<TxHash, TxStatus, hashbrown::hash_map::DefaultHashBuilder>,
/// TODO: this map is going to grow forever unless we do some sort of pruning. maybe store pruned in redis?
/// all blocks, including orphans
pub(super) block_hashes: BlockHashesCache,
/// blocks on the heaviest chain
pub(super) block_numbers: Cache<U64, H256, hashbrown::hash_map::DefaultHashBuilder>,
/// TODO: this map is going to grow forever unless we do some sort of pruning. maybe store pruned in redis?
/// TODO: what should we use for edges?
pub(super) blockchain_graphmap: AsyncRwLock<DiGraphMap<H256, u32>>,
pub(super) min_synced_rpcs: usize,
pub(super) min_sum_soft_limit: u32,
}
impl Web3Connections {
/// Spawn durable connections to multiple Web3 providers.
#[allow(clippy::too_many_arguments)]
pub async fn spawn(
chain_id: u64,
server_configs: HashMap<String, Web3ConnectionConfig>,
http_client: Option<reqwest::Client>,
redis_pool: Option<redis_rate_limiter::RedisPool>,
block_map: BlockHashesCache,
head_block_sender: Option<watch::Sender<ArcBlock>>,
min_sum_soft_limit: u32,
min_synced_rpcs: usize,
pending_tx_sender: Option<broadcast::Sender<TxStatus>>,
pending_transactions: Cache<TxHash, TxStatus, hashbrown::hash_map::DefaultHashBuilder>,
open_request_handle_metrics: Arc<OpenRequestHandleMetrics>,
) -> anyhow::Result<(Arc<Self>, AnyhowJoinHandle<()>)> {
let (pending_tx_id_sender, pending_tx_id_receiver) = flume::unbounded();
let (block_sender, block_receiver) = flume::unbounded::<BlockAndRpc>();
let http_interval_sender = if http_client.is_some() {
let (sender, receiver) = broadcast::channel(1);
drop(receiver);
// TODO: what interval? follow a websocket also? maybe by watching synced connections with a timeout. will need debounce
let mut interval = interval(Duration::from_secs(13));
interval.set_missed_tick_behavior(MissedTickBehavior::Delay);
let sender = Arc::new(sender);
let f = {
let sender = sender.clone();
async move {
loop {
// TODO: every time a head_block arrives (with a small delay for known slow servers), or on the interval.
interval.tick().await;
trace!("http interval ready");
// errors are okay. they mean that all receivers have been dropped
let _ = sender.send(());
}
}
};
// TODO: do something with this handle?
tokio::spawn(f);
Some(sender)
} else {
None
};
// turn configs into connections (in parallel)
// TODO: move this into a helper function. then we can use it when configs change (will need a remove function too)
let spawn_handles: Vec<_> = server_configs
.into_iter()
.map(|(server_name, server_config)| {
let http_client = http_client.clone();
let redis_pool = redis_pool.clone();
let http_interval_sender = http_interval_sender.clone();
let block_sender = if head_block_sender.is_some() {
Some(block_sender.clone())
} else {
None
};
let pending_tx_id_sender = Some(pending_tx_id_sender.clone());
let block_map = block_map.clone();
let open_request_handle_metrics = open_request_handle_metrics.clone();
tokio::spawn(async move {
server_config
.spawn(
server_name,
redis_pool,
chain_id,
http_client,
http_interval_sender,
block_map,
block_sender,
pending_tx_id_sender,
open_request_handle_metrics,
)
.await
})
})
.collect();
// map of connection names to their connection
let mut connections = HashMap::new();
let mut handles = vec![];
// TODO: futures unordered?
for x in join_all(spawn_handles).await {
// TODO: how should we handle errors here? one rpc being down shouldn't cause the program to exit
match x {
Ok(Ok((connection, handle))) => {
connections.insert(connection.name.clone(), connection);
handles.push(handle);
}
Ok(Err(err)) => {
// if we got an error here, it is not retryable
// TODO: include context about which connection failed
error!(?err, "Unable to create connection");
}
Err(err) => {
return Err(err.into());
}
}
}
if connections.len() < min_synced_rpcs {
return Err(anyhow::anyhow!(
"Only {}/{} connections!",
connections.len(),
min_synced_rpcs
));
}
// TODO: safety check on sum soft limit
let synced_connections = SyncedConnections::default();
// TODO: max_capacity and time_to_idle from config
// all block hashes are the same size, so no need for weigher
let block_hashes = Cache::builder()
.time_to_idle(Duration::from_secs(600))
.max_capacity(10_000)
.build_with_hasher(hashbrown::hash_map::DefaultHashBuilder::new());
// all block numbers are the same size, so no need for weigher
let block_numbers = Cache::builder()
.time_to_idle(Duration::from_secs(600))
.max_capacity(10_000)
.build_with_hasher(hashbrown::hash_map::DefaultHashBuilder::new());
let connections = Arc::new(Self {
conns: connections,
synced_connections: ArcSwap::new(Arc::new(synced_connections)),
pending_transactions,
block_hashes,
block_numbers,
blockchain_graphmap: Default::default(),
min_sum_soft_limit,
min_synced_rpcs,
});
let handle = {
let connections = connections.clone();
tokio::spawn(async move {
// TODO: try_join_all with the other handles here
connections
.subscribe(
pending_tx_id_receiver,
block_receiver,
head_block_sender,
pending_tx_sender,
)
.await
})
};
Ok((connections, handle))
}
pub fn get(&self, conn_name: &str) -> Option<&Arc<Web3Connection>> {
self.conns.get(conn_name)
}
/// subscribe to blocks and transactions from all the backend rpcs.
/// blocks are processed by all the `Web3Connection`s and then sent to the `block_receiver`
/// transaction ids from all the `Web3Connection`s are deduplicated and forwarded to `pending_tx_sender`
async fn subscribe(
self: Arc<Self>,
pending_tx_id_receiver: flume::Receiver<TxHashAndRpc>,
block_receiver: flume::Receiver<BlockAndRpc>,
head_block_sender: Option<watch::Sender<ArcBlock>>,
pending_tx_sender: Option<broadcast::Sender<TxStatus>>,
) -> anyhow::Result<()> {
let mut futures = vec![];
// setup the transaction funnel
// it skips any duplicates (unless they are being orphaned)
// fetches new transactions from the notifying rpc
// forwards new transacitons to pending_tx_receipt_sender
if let Some(pending_tx_sender) = pending_tx_sender.clone() {
let clone = self.clone();
let handle = task::spawn(async move {
// TODO: set up this future the same as the block funnel
while let Ok((pending_tx_id, rpc)) = pending_tx_id_receiver.recv_async().await {
let f = clone.clone().process_incoming_tx_id(
rpc,
pending_tx_id,
pending_tx_sender.clone(),
);
tokio::spawn(f);
}
Ok(())
});
futures.push(flatten_handle(handle));
}
// setup the block funnel
if let Some(head_block_sender) = head_block_sender {
let connections = Arc::clone(&self);
let pending_tx_sender = pending_tx_sender.clone();
let handle = task::Builder::default()
.name("process_incoming_blocks")
.spawn(async move {
connections
.process_incoming_blocks(
block_receiver,
head_block_sender,
pending_tx_sender,
)
.await
})?;
futures.push(flatten_handle(handle));
}
if futures.is_empty() {
// no transaction or block subscriptions.
let handle = task::Builder::default().name("noop").spawn(async move {
loop {
sleep(Duration::from_secs(600)).await;
// TODO: "every interval, check that the provider is still connected"
}
})?;
futures.push(flatten_handle(handle));
}
if let Err(e) = try_join_all(futures).await {
error!("subscriptions over: {:?}", self);
return Err(e);
}
info!("subscriptions over: {:?}", self);
Ok(())
}
/// Send the same request to all the handles. Returning the most common success or most common error.
pub async fn try_send_parallel_requests(
&self,
active_request_handles: Vec<OpenRequestHandle>,
method: &str,
params: Option<&serde_json::Value>,
// TODO: remove this box once i figure out how to do the options
) -> Result<Box<RawValue>, ProviderError> {
// TODO: if only 1 active_request_handles, do self.try_send_request?
let responses = active_request_handles
.into_iter()
.map(|active_request_handle| async move {
let result: Result<Box<RawValue>, _> = active_request_handle
.request(method, &json!(&params), tracing::Level::ERROR.into())
.await;
result
})
.collect::<FuturesUnordered<_>>()
.collect::<Vec<Result<Box<RawValue>, ProviderError>>>()
.await;
// TODO: Strings are not great keys, but we can't use RawValue or ProviderError as keys because they don't implement Hash or Eq
let mut count_map: HashMap<String, Result<Box<RawValue>, ProviderError>> = HashMap::new();
let mut counts: Counter<String> = Counter::new();
let mut any_ok = false;
for response in responses {
// TODO: i think we need to do something smarter with provider error. we at least need to wrap it up as JSON
// TODO: emit stats errors?
let s = format!("{:?}", response);
if count_map.get(&s).is_none() {
if response.is_ok() {
any_ok = true;
}
count_map.insert(s.clone(), response);
}
counts.update([s].into_iter());
}
for (most_common, _) in counts.most_common_ordered() {
let most_common = count_map.remove(&most_common).unwrap();
if any_ok && most_common.is_err() {
// errors were more common, but we are going to skip them because we got an okay
continue;
} else {
// return the most common
return most_common;
}
}
// TODO: what should we do if we get here? i don't think we will
panic!("i don't think this is possible")
}
/// get the best available rpc server
pub async fn next_upstream_server(
&self,
authorized_request: Option<&Arc<AuthorizedRequest>>,
skip: &[Arc<Web3Connection>],
min_block_needed: Option<&U64>,
) -> anyhow::Result<OpenRequestResult> {
let mut earliest_retry_at = None;
// filter the synced rpcs
// TODO: we are going to be checking "has_block_data" a lot now. i think we pretty much always have min_block_needed now that we override "latest"
let mut synced_rpcs: Vec<Arc<Web3Connection>> =
if let Some(min_block_needed) = min_block_needed {
self.conns
.values()
.filter(|x| !skip.contains(x))
.filter(|x| x.has_block_data(min_block_needed))
.cloned()
.collect()
} else {
self.synced_connections
.load()
.conns
.iter()
.filter(|x| !skip.contains(x))
.cloned()
.collect()
};
if synced_rpcs.is_empty() {
// TODO: what should happen here? automatic retry?
// TODO: more detailed error
return Err(anyhow::anyhow!("not synced"));
}
// we sort on a bunch of values. cache them here so that we don't do this math multiple times.
let sort_cache: HashMap<_, _> = synced_rpcs
.iter()
.map(|rpc| {
// TODO: get active requests and the soft limit out of redis?
let weight = rpc.weight;
let active_requests = rpc.active_requests();
let soft_limit = rpc.soft_limit;
let utilization = active_requests as f32 / soft_limit as f32;
// TODO: double check this sorts how we want
(rpc.clone(), (weight, utilization, Reverse(soft_limit)))
})
.collect();
synced_rpcs.sort_unstable_by(|a, b| {
let a_sorts = sort_cache.get(a).expect("sort_cache should always have a");
let b_sorts = sort_cache.get(b).expect("sort_cache should always have b");
// partial_cmp because we are comparing floats
a_sorts.partial_cmp(b_sorts).unwrap_or(cmp::Ordering::Equal)
});
// now that the rpcs are sorted, try to get an active request handle for one of them
for rpc in synced_rpcs.into_iter() {
// increment our connection counter
match rpc.try_request_handle(authorized_request).await {
Ok(OpenRequestResult::Handle(handle)) => {
trace!("next server on {:?}: {:?}", self, rpc);
return Ok(OpenRequestResult::Handle(handle));
}
Ok(OpenRequestResult::RetryAt(retry_at)) => {
earliest_retry_at = earliest_retry_at.min(Some(retry_at));
}
Ok(OpenRequestResult::RetryNever) => {
// TODO: log a warning?
}
Err(err) => {
// TODO: log a warning?
warn!(?err, "No request handle for {}", rpc)
}
}
}
warn!("no servers on {:?}! {:?}", self, earliest_retry_at);
match earliest_retry_at {
None => todo!(),
Some(earliest_retry_at) => Ok(OpenRequestResult::RetryAt(earliest_retry_at)),
}
}
/// get all rpc servers that are not rate limited
/// returns servers even if they aren't in sync. This is useful for broadcasting signed transactions
// TODO: better type on this that can return an anyhow::Result
pub async fn upstream_servers(
&self,
authorized_request: Option<&Arc<AuthorizedRequest>>,
block_needed: Option<&U64>,
) -> Result<Vec<OpenRequestHandle>, Option<Instant>> {
let mut earliest_retry_at = None;
// TODO: with capacity?
let mut selected_rpcs = vec![];
for connection in self.conns.values() {
if let Some(block_needed) = block_needed {
if !connection.has_block_data(block_needed) {
continue;
}
}
// check rate limits and increment our connection counter
match connection.try_request_handle(authorized_request).await {
Ok(OpenRequestResult::RetryAt(retry_at)) => {
// this rpc is not available. skip it
earliest_retry_at = earliest_retry_at.min(Some(retry_at));
}
Ok(OpenRequestResult::Handle(handle)) => selected_rpcs.push(handle),
Ok(OpenRequestResult::RetryNever) => {
warn!("no request handle for {}", connection)
}
Err(err) => {
warn!(?err, "error getting request handle for {}", connection)
}
}
}
if !selected_rpcs.is_empty() {
return Ok(selected_rpcs);
}
// return the earliest retry_after (if no rpcs are synced, this will be None)
Err(earliest_retry_at)
}
/// be sure there is a timeout on this or it might loop forever
pub async fn try_send_best_upstream_server(
&self,
authorized_request: Option<&Arc<AuthorizedRequest>>,
request: JsonRpcRequest,
min_block_needed: Option<&U64>,
) -> anyhow::Result<JsonRpcForwardedResponse> {
let mut skip_rpcs = vec![];
// TODO: maximum retries?
loop {
if skip_rpcs.len() == self.conns.len() {
break;
}
match self
.next_upstream_server(authorized_request, &skip_rpcs, min_block_needed)
.await?
{
OpenRequestResult::Handle(active_request_handle) => {
// save the rpc in case we get an error and want to retry on another server
skip_rpcs.push(active_request_handle.clone_connection());
// TODO: get the log percent from the user data
let response_result = active_request_handle
.request(
&request.method,
&json!(request.params),
RequestErrorHandler::SaveReverts,
)
.await;
match JsonRpcForwardedResponse::try_from_response_result(
response_result,
request.id.clone(),
) {
Ok(response) => {
if let Some(error) = &response.error {
trace!(?response, "rpc error");
// some errors should be retried on other nodes
if error.code == -32000 {
let error_msg = error.message.as_str();
// TODO: regex?
let retry_prefixes = [
"header not found",
"header for hash not found",
"missing trie node",
"node not started",
"RPC timeout",
];
for retry_prefix in retry_prefixes {
if error_msg.starts_with(retry_prefix) {
continue;
}
}
}
} else {
trace!(?response, "rpc success");
}
return Ok(response);
}
Err(e) => {
let rpc = skip_rpcs
.last()
.expect("there must have been a provider if we got an error");
warn!(%rpc, ?e, "Backend server error! Retrying on another");
// TODO: sleep how long? until synced_connections changes or rate limits are available
// sleep(Duration::from_millis(100)).await;
continue;
}
}
}
OpenRequestResult::RetryAt(retry_at) => {
// TODO: move this to a helper function
// sleep (TODO: with a lock?) until our rate limits should be available
// TODO: if a server catches up sync while we are waiting, we could stop waiting
warn!(?retry_at, "All rate limits exceeded. Sleeping");
sleep_until(retry_at).await;
continue;
}
OpenRequestResult::RetryNever => {
warn!(?self, "No server handles!");
// TODO: subscribe to something on synced connections. maybe it should just be a watch channel
sleep(Duration::from_millis(200)).await;
continue;
}
}
}
Err(anyhow::anyhow!("all {} tries exhausted", skip_rpcs.len()))
}
/// be sure there is a timeout on this or it might loop forever
#[instrument]
pub async fn try_send_all_upstream_servers(
&self,
authorized_request: Option<&Arc<AuthorizedRequest>>,
request: JsonRpcRequest,
block_needed: Option<&U64>,
) -> anyhow::Result<JsonRpcForwardedResponse> {
loop {
match self
.upstream_servers(authorized_request, block_needed)
.await
{
Ok(active_request_handles) => {
// TODO: benchmark this compared to waiting on unbounded futures
// TODO: do something with this handle?
// TODO: this is not working right. simplify
let quorum_response = self
.try_send_parallel_requests(
active_request_handles,
request.method.as_ref(),
request.params.as_ref(),
)
.await?;
let response = JsonRpcForwardedResponse {
jsonrpc: "2.0".to_string(),
id: request.id,
result: Some(quorum_response),
error: None,
};
return Ok(response);
}
Err(None) => {
warn!(?self, "No servers in sync! Retrying");
// TODO: i don't think this will ever happen
// TODO: return a 502? if it does?
// return Err(anyhow::anyhow!("no available rpcs!"));
// TODO: sleep how long?
// TODO: subscribe to something in SyncedConnections instead
sleep(Duration::from_millis(200)).await;
continue;
}
Err(Some(retry_at)) => {
// TODO: move this to a helper function
// sleep (TODO: with a lock?) until our rate limits should be available
// TODO: if a server catches up sync while we are waiting, we could stop waiting
warn!("All rate limits exceeded. Sleeping");
sleep_until(retry_at).await;
continue;
}
}
}
}
}
impl fmt::Debug for Web3Connections {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
// TODO: the default formatter takes forever to write. this is too quiet though
f.debug_struct("Web3Connections")
.field("conns", &self.conns)
.finish_non_exhaustive()
}
}
impl Serialize for Web3Connections {
fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
where
S: Serializer,
{
let mut state = serializer.serialize_struct("Web3Connections", 6)?;
let conns: Vec<&Web3Connection> = self.conns.values().map(|x| x.as_ref()).collect();
state.serialize_field("conns", &conns)?;
let synced_connections = &**self.synced_connections.load();
state.serialize_field("synced_connections", synced_connections)?;
self.block_hashes.sync();
self.block_numbers.sync();
state.serialize_field("block_hashes_count", &self.block_hashes.entry_count())?;
state.serialize_field("block_hashes_size", &self.block_hashes.weighted_size())?;
state.serialize_field("block_numbers_count", &self.block_numbers.entry_count())?;
state.serialize_field("block_numbers_size", &self.block_numbers.weighted_size())?;
state.end()
}
}