dont fear locks and better serializing

This commit is contained in:
Bryan Stitt 2022-05-06 05:44:30 +00:00
parent d3859b463e
commit cf4055e2b1
5 changed files with 136 additions and 80 deletions

7
Cargo.lock generated

@ -59,12 +59,6 @@ version = "1.0.57"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "08f9b8508dccb7687a1d6c4ce66b2b0ecef467c94667de27d8d7fe1f8d2a9cdc"
[[package]]
name = "arc-swap"
version = "1.5.0"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "c5d78ce20460b82d3fa150275ed9d55e21064fc7951177baacf86a145c4a4b1f"
[[package]]
name = "argh"
version = "0.1.7"
@ -3851,7 +3845,6 @@ name = "web3-proxy"
version = "0.1.0"
dependencies = [
"anyhow",
"arc-swap",
"argh",
"derive_more",
"ethers",

@ -7,7 +7,6 @@ edition = "2021"
[dependencies]
anyhow = "1.0.57"
arc-swap = "1.5.0"
argh = "0.1.7"
# axum = "*" # TODO: use this instead of warp?
derive_more = "0.99.17"

@ -133,13 +133,14 @@ impl Web3Connection {
pub async fn new_heads(
self: Arc<Self>,
connections: Option<Arc<Web3Connections>>,
best_head_block_number: Arc<AtomicU64>,
) -> anyhow::Result<()> {
info!("Watching new_heads on {}", self);
match &self.provider {
Web3Provider::Http(provider) => {
// there is a "watch_blocks" function, but a lot of public nodes do not support the necessary rpc endpoints
// TODO: what should this interval be? probably some fraction of block time
// TODO: what should this interval be? probably some fraction of block time. set automatically?
// TODO: maybe it would be better to have one interval for all of the http providers, but this works for now
let mut interval = interval(Duration::from_secs(2));
interval.set_missed_tick_behavior(MissedTickBehavior::Delay);
@ -149,7 +150,6 @@ impl Web3Connection {
// TODO: if error or rate limit, increase interval?
interval.tick().await;
// rate limits
let active_request_handle = self.wait_for_request_handle().await;
let block_number = provider.get_block_number().await.map(|x| x.as_u64())?;
@ -165,6 +165,14 @@ impl Web3Connection {
if old_block_number != block_number {
info!("new block on {}: {}", self, block_number);
// we don't care about this result.
let _ = best_head_block_number.compare_exchange(
old_block_number,
block_number,
atomic::Ordering::AcqRel,
atomic::Ordering::Acquire,
);
if let Some(connections) = &connections {
connections.update_synced_rpcs(&self, block_number)?;
}
@ -193,8 +201,17 @@ impl Web3Connection {
info!("current block on {}: {}", self, block_number);
self.head_block_number
.store(block_number, atomic::Ordering::Release);
let old_block_number = self
.head_block_number
.swap(block_number, atomic::Ordering::Release);
// we don't care about this result
let _ = best_head_block_number.compare_exchange(
old_block_number,
block_number,
atomic::Ordering::AcqRel,
atomic::Ordering::Acquire,
);
if let Some(connections) = &connections {
connections.update_synced_rpcs(&self, block_number)?;
@ -209,6 +226,9 @@ impl Web3Connection {
self.head_block_number
.store(block_number, atomic::Ordering::Release);
// TODO: what ordering?
best_head_block_number.fetch_max(block_number, atomic::Ordering::AcqRel);
info!("new block on {}: {}", self, block_number);
if let Some(connections) = &connections {
@ -284,7 +304,7 @@ impl ActiveRequestHandle {
self,
method: &str,
params: &serde_json::value::RawValue,
) -> Result<JsonRpcForwardedResponse, ethers::prelude::ProviderError> {
) -> Result<Box<RawValue>, ethers::prelude::ProviderError> {
match &self.0.provider {
Web3Provider::Http(provider) => provider.request(method, params).await,
Web3Provider::Ws(provider) => provider.request(method, params).await,
@ -347,11 +367,15 @@ impl fmt::Debug for JsonRpcRequest {
}
}
// TODO: check for errors too!
#[derive(Clone, Deserialize, Serialize)]
#[derive(Clone, Serialize)]
pub struct JsonRpcForwardedResponse {
pub jsonrpc: String,
pub id: Box<RawValue>,
pub result: Box<RawValue>,
#[serde(skip_serializing_if = "Option::is_none")]
pub result: Option<Box<RawValue>>,
#[serde(skip_serializing_if = "Option::is_none")]
pub error: Option<String>,
// TODO: optional error
}
impl fmt::Debug for JsonRpcForwardedResponse {

@ -1,19 +1,20 @@
///! Communicate with a group of web3 providers
use arc_swap::ArcSwap;
use derive_more::From;
use futures::stream::FuturesUnordered;
use futures::StreamExt;
use governor::clock::{QuantaClock, QuantaInstant};
use governor::NotUntil;
use hashbrown::HashMap;
use parking_lot::RwLock;
use serde_json::value::RawValue;
use std::cmp;
use std::fmt;
use std::sync::atomic::{self, AtomicU64};
use std::sync::Arc;
use tracing::warn;
use crate::config::Web3ConnectionConfig;
use crate::connection::{ActiveRequestHandle, JsonRpcForwardedResponse, Web3Connection};
use crate::connection::{ActiveRequestHandle, Web3Connection};
#[derive(Clone, Default)]
struct SyncedConnections {
@ -44,8 +45,9 @@ impl SyncedConnections {
pub struct Web3Connections {
inner: Vec<Arc<Web3Connection>>,
/// TODO: what is the best type for this? Heavy reads with writes every few seconds. When writes happen, there is a burst of them
/// TODO: arcswap was a lot faster, but i think we need a lock for proper logic
synced_connections: ArcSwap<SyncedConnections>,
/// TODO: we probably need a better lock on this
synced_connections: RwLock<SyncedConnections>,
best_head_block_number: Arc<AtomicU64>,
}
impl fmt::Debug for Web3Connections {
@ -59,7 +61,7 @@ impl fmt::Debug for Web3Connections {
impl Web3Connections {
pub async fn try_new(
// TODO: servers should be a Web3ConnectionBuilder struct
best_head_block_number: Arc<AtomicU64>,
servers: Vec<Web3ConnectionConfig>,
http_client: Option<reqwest::Client>,
clock: &QuantaClock,
@ -78,20 +80,25 @@ impl Web3Connections {
// TODO: exit if no connections?
let connections = Arc::new(Self {
best_head_block_number: best_head_block_number.clone(),
inner: connections,
synced_connections: ArcSwap::new(Arc::new(SyncedConnections::new(num_connections))),
synced_connections: RwLock::new(SyncedConnections::new(num_connections)),
});
for connection in connections.inner.iter() {
// subscribe to new heads in a spawned future
// TODO: channel instead. then we can have one future with write access to a left-right
// TODO: channel instead. then we can have one future with write access to a left-right?
let connection = Arc::clone(connection);
let connections = connections.clone();
let best_head_block_number = best_head_block_number.clone();
tokio::spawn(async move {
let url = connection.url().to_string();
// TODO: instead of passing Some(connections), pass Some(channel_sender). Then listen on the receiver below to keep local heads up-to-date
if let Err(e) = connection.new_heads(Some(connections)).await {
if let Err(e) = connection
.new_heads(Some(connections), best_head_block_number)
.await
{
warn!("new_heads error on {}: {:?}", url, e);
}
});
@ -101,15 +108,15 @@ impl Web3Connections {
}
pub fn head_block_number(&self) -> u64 {
self.synced_connections.load().head_block_number
self.best_head_block_number.load(atomic::Ordering::Acquire)
}
pub async fn try_send_request<'a>(
pub async fn try_send_request(
&self,
connection_handle: ActiveRequestHandle,
method: &str,
params: &RawValue,
) -> anyhow::Result<JsonRpcForwardedResponse> {
) -> anyhow::Result<Box<RawValue>> {
// connection.in_active_requests was called when this rpc was selected
let response = connection_handle.request(method, params).await;
@ -124,7 +131,7 @@ impl Web3Connections {
connections: Vec<ActiveRequestHandle>,
method: String,
params: Box<RawValue>,
response_sender: flume::Sender<anyhow::Result<JsonRpcForwardedResponse>>,
response_sender: flume::Sender<anyhow::Result<Box<RawValue>>>,
) -> anyhow::Result<()> {
let mut unordered_futures = FuturesUnordered::new();
@ -185,35 +192,38 @@ impl Web3Connections {
rpc: &Arc<Web3Connection>,
new_block: u64,
) -> anyhow::Result<()> {
// TODO: try a left_right instead of an ArcSwap.
let synced_connections = self.synced_connections.load();
let mut synced_connections = self.synced_connections.write();
// should we load new_block here?
let current_block_number = synced_connections.head_block_number;
let mut new_synced_connections: SyncedConnections =
match synced_connections.head_block_number.cmp(&new_block) {
cmp::Ordering::Equal => {
// this rpc is synced, but it isn't the first to this block
(**synced_connections).to_owned()
}
cmp::Ordering::Less => {
// this is a new head block. clear the current synced connections
// TODO: this is too verbose with a bunch of tiers. include the tier
// info!("new head block from {:?}: {}", rpc, new_block);
let best_head_block = self.head_block_number();
let mut new_synced_connections = SyncedConnections::new(self.inner.len());
match current_block_number.cmp(&best_head_block) {
cmp::Ordering::Equal => {
// this rpc tier is synced, and it isn't the first to this block
}
cmp::Ordering::Less => {}
cmp::Ordering::Greater => {}
}
// synced_connections.inner.clear();
match current_block_number.cmp(&new_block) {
cmp::Ordering::Equal => {
// this rpc is synced, and it isn't the first to this block
}
cmp::Ordering::Less => {
// this is a new head block. clear the current synced connections
// TODO: this is too verbose with a bunch of tiers. include the tier
// info!("new head block from {:?}: {}", rpc, new_block);
new_synced_connections.head_block_number = new_block;
synced_connections.inner.clear();
new_synced_connections
}
cmp::Ordering::Greater => {
// not the latest block. return now
return Ok(());
}
};
synced_connections.head_block_number = new_block;
}
cmp::Ordering::Greater => {
// not the latest block. return now
return Ok(());
}
}
let rpc_index = self
.inner
@ -221,10 +231,7 @@ impl Web3Connections {
.position(|x| x.url() == rpc.url())
.unwrap();
new_synced_connections.inner.push(rpc_index);
self.synced_connections
.swap(Arc::new(new_synced_connections));
synced_connections.inner.push(rpc_index);
Ok(())
}
@ -236,7 +243,7 @@ impl Web3Connections {
let mut earliest_not_until = None;
// TODO: this clone is probably not the best way to do this
let mut synced_rpc_indexes = self.synced_connections.load().inner.clone();
let mut synced_rpc_indexes = self.synced_connections.read().inner.clone();
let cache: HashMap<usize, u32> = synced_rpc_indexes
.iter()

@ -3,12 +3,13 @@ mod connection;
mod connections;
use config::Web3ConnectionConfig;
use connection::JsonRpcForwardedResponse;
use futures::future;
use governor::clock::{Clock, QuantaClock};
use linkedhashmap::LinkedHashMap;
use serde_json::json;
use std::fmt;
use std::fs;
use std::sync::atomic::{self, AtomicU64};
use std::sync::Arc;
use std::time::Duration;
use tokio::sync::RwLock;
@ -28,11 +29,17 @@ static APP_USER_AGENT: &str = concat!(
env!("CARGO_PKG_VERSION"),
);
const RESPONSE_CACHE_CAP: usize = 128;
// TODO: put this in config? what size should we do?
const RESPONSE_CACHE_CAP: usize = 1024;
/// TODO: these types are probably very bad keys and values. i couldn't get caching of warp::reply::Json to work
type ResponseLruCache = RwLock<LinkedHashMap<(u64, String, String), JsonRpcForwardedResponse>>;
/// The application
// TODO: this debug impl is way too verbose. make something smaller
// TODO: if Web3ProxyApp is always in an Arc, i think we can avoid having at least some of these internal things in arcs
pub struct Web3ProxyApp {
best_head_block_number: Arc<AtomicU64>,
/// clock used for rate limiting
/// TODO: use tokio's clock (will require a different ratelimiting crate)
clock: QuantaClock,
@ -40,14 +47,18 @@ pub struct Web3ProxyApp {
balanced_rpc_tiers: Vec<Arc<Web3Connections>>,
/// Send private requests (like eth_sendRawTransaction) to all these servers
private_rpcs: Option<Arc<Web3Connections>>,
/// TODO: these types are probably very bad keys and values. i couldn't get caching of warp::reply::Json to work
response_cache: RwLock<LinkedHashMap<(u64, String, String), serde_json::Value>>,
response_cache: ResponseLruCache,
}
impl fmt::Debug for Web3ProxyApp {
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("Web3ProxyApp").finish_non_exhaustive()
f.debug_struct("Web3ProxyApp")
.field(
"best_head_block_number",
&self.best_head_block_number.load(atomic::Ordering::Relaxed),
)
.finish_non_exhaustive()
}
}
@ -58,6 +69,8 @@ impl Web3ProxyApp {
) -> anyhow::Result<Web3ProxyApp> {
let clock = QuantaClock::default();
let best_head_block_number = Arc::new(AtomicU64::new(0));
// make a http shared client
// TODO: how should we configure the connection pool?
// TODO: 5 minutes is probably long enough. unlimited is a bad idea if something is wrong with the remote server
@ -70,7 +83,12 @@ impl Web3ProxyApp {
// TODO: attach context to this error
let balanced_rpc_tiers =
future::join_all(balanced_rpc_tiers.into_iter().map(|balanced_rpc_tier| {
Web3Connections::try_new(balanced_rpc_tier, Some(http_client.clone()), &clock)
Web3Connections::try_new(
best_head_block_number.clone(),
balanced_rpc_tier,
Some(http_client.clone()),
&clock,
)
}))
.await
.into_iter()
@ -82,10 +100,19 @@ impl Web3ProxyApp {
// TODO: instead of None, set it to a list of all the rpcs from balanced_rpc_tiers. that way we broadcast very loudly
None
} else {
Some(Web3Connections::try_new(private_rpcs, Some(http_client), &clock).await?)
Some(
Web3Connections::try_new(
best_head_block_number.clone(),
private_rpcs,
Some(http_client),
&clock,
)
.await?,
)
};
Ok(Web3ProxyApp {
best_head_block_number,
clock,
balanced_rpc_tiers,
private_rpcs,
@ -113,6 +140,7 @@ impl Web3ProxyApp {
let method = json_body.method.clone();
let params = json_body.params.clone();
// TODO: benchmark this compared to waiting on unbounded futures
tokio::spawn(async move {
connections
.try_send_requests(upstream_servers, method, params, tx)
@ -120,14 +148,16 @@ impl Web3ProxyApp {
});
// wait for the first response
let response = rx.recv_async().await?;
let backend_response = rx.recv_async().await?;
if let Ok(partial_response) = response {
let response = json!({
"jsonrpc": "2.0",
"id": json_body.id,
"result": partial_response
});
if let Ok(backend_response) = backend_response {
// TODO: i think we
let response = JsonRpcForwardedResponse {
jsonrpc: "2.0".to_string(),
id: json_body.id,
result: Some(backend_response),
error: None,
};
return Ok(warp::reply::json(&response));
}
}
@ -181,17 +211,19 @@ impl Web3ProxyApp {
// TODO: trace here was really slow with millions of requests.
// info!("forwarding request from {}", upstream_server);
let response = json!({
let response = JsonRpcForwardedResponse {
// TODO: re-use their jsonrpc?
"jsonrpc": "2.0",
"id": json_body.id,
jsonrpc: "2.0".to_string(),
id: json_body.id,
// TODO: since we only use the result here, should that be all we return from try_send_request?
"result": partial_response.result,
});
result: Some(partial_response),
error: None,
};
// TODO: small race condidition here. parallel requests with the same query will both be saved to the cache
let mut response_cache = self.response_cache.write().await;
// TODO: cache the warp::reply to save us serializing every time
response_cache.insert(cache_key, response.clone());
if response_cache.len() >= RESPONSE_CACHE_CAP {
response_cache.pop_front();
@ -201,11 +233,12 @@ impl Web3ProxyApp {
}
Err(e) => {
// TODO: what is the proper format for an error?
json!({
"jsonrpc": "2.0",
"id": json_body.id,
"error": format!("{}", e)
})
JsonRpcForwardedResponse {
jsonrpc: "2.0".to_string(),
id: json_body.id,
result: None,
error: Some(format!("{}", e)),
}
}
};