web3-proxy/web3_proxy/src/sub_commands/proxyd.rs

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#![forbid(unsafe_code)]
use crate::app::{flatten_handle, flatten_handles, Web3ProxyApp};
use crate::config::TopConfig;
use crate::{frontend, prometheus};
use argh::FromArgs;
use futures::StreamExt;
use num::Zero;
use std::path::PathBuf;
use std::sync::atomic::AtomicU16;
use std::sync::Arc;
use std::time::Duration;
use std::{fs, thread};
use tokio::select;
use tokio::sync::broadcast;
use tokio::time::{sleep_until, Instant};
use tracing::{error, info, trace, warn};
/// start the main proxy daemon
#[derive(FromArgs, PartialEq, Debug, Eq)]
#[argh(subcommand, name = "proxyd")]
pub struct ProxydSubCommand {
/// path to a toml of rpc servers
/// what port the proxy should listen on
#[argh(option, default = "8544")]
pub port: u16,
/// what port the proxy should expose prometheus stats on
#[argh(option, default = "8543")]
pub prometheus_port: u16,
}
impl ProxydSubCommand {
pub async fn main(
self,
top_config: TopConfig,
top_config_path: PathBuf,
num_workers: usize,
) -> anyhow::Result<()> {
let (shutdown_sender, _) = broadcast::channel(1);
// TODO: i think there is a small race. if config_path changes
let frontend_port = Arc::new(self.port.into());
let prometheus_port = Arc::new(self.prometheus_port.into());
let (flush_stat_buffer_sender, _) = broadcast::channel(1);
Self::_main(
top_config,
Some(top_config_path),
frontend_port,
prometheus_port,
num_workers,
shutdown_sender,
flush_stat_buffer_sender,
)
.await
}
/// this shouldn't really be pub except it makes test fixtures easier
pub async fn _main(
top_config: TopConfig,
top_config_path: Option<PathBuf>,
frontend_port: Arc<AtomicU16>,
prometheus_port: Arc<AtomicU16>,
num_workers: usize,
frontend_shutdown_sender: broadcast::Sender<()>,
flush_stat_buffer_sender: broadcast::Sender<()>,
) -> anyhow::Result<()> {
// tokio has code for catching ctrl+c so we use that to shut down in most cases
// frontend_shutdown_sender is currently only used in tests, but we might make a /shutdown endpoint or something
// we do not need this receiver. new receivers are made by `shutdown_sender.subscribe()`
let (app_shutdown_sender, _app_shutdown_receiver) = broadcast::channel(1);
let frontend_shutdown_receiver = frontend_shutdown_sender.subscribe();
let prometheus_shutdown_receiver = app_shutdown_sender.subscribe();
// TODO: should we use a watch or broadcast for these?
let (frontend_shutdown_complete_sender, mut frontend_shutdown_complete_receiver) =
broadcast::channel(1);
// start the main app
let mut spawned_app = Web3ProxyApp::spawn(
frontend_port,
prometheus_port,
top_config.clone(),
num_workers,
app_shutdown_sender.clone(),
flush_stat_buffer_sender.subscribe(),
)
.await?;
let mut head_block_receiver = spawned_app.app.head_block_receiver();
// start thread for watching config
if let Some(top_config_path) = top_config_path {
let config_sender = spawned_app.new_top_config;
{
let mut current_config = config_sender.borrow().clone();
thread::spawn(move || loop {
match fs::read_to_string(&top_config_path) {
Ok(new_top_config) => match toml::from_str::<TopConfig>(&new_top_config) {
Ok(new_top_config) => {
if new_top_config != current_config {
// TODO: print the differences
// TODO: first run seems to always see differences. why?
info!("config @ {:?} changed", top_config_path);
config_sender.send(new_top_config.clone()).unwrap();
current_config = new_top_config;
}
}
Err(err) => {
// TODO: panic?
error!("Unable to parse config! {:#?}", err);
}
},
Err(err) => {
// TODO: panic?
error!("Unable to read config! {:#?}", err);
}
}
thread::sleep(Duration::from_secs(10));
});
}
}
// start the prometheus metrics port
let prometheus_handle = tokio::spawn(prometheus::serve(
spawned_app.app.clone(),
prometheus_shutdown_receiver,
));
info!("waiting for head block");
let max_wait_until = Instant::now() + Duration::from_secs(35);
loop {
select! {
_ = sleep_until(max_wait_until) => {
return Err(anyhow::anyhow!("oh no! we never got a head block!"))
}
_ = head_block_receiver.changed() => {
if let Some(head_block) = spawned_app
.app
.head_block_receiver()
.borrow_and_update()
.as_ref()
{
info!(head_hash=?head_block.hash(), head_num=%head_block.number());
break;
} else {
info!("no head block yet!");
continue;
}
}
}
}
// start the frontend port
let frontend_handle = tokio::spawn(frontend::serve(
spawned_app.app,
frontend_shutdown_receiver,
frontend_shutdown_complete_sender,
));
let frontend_handle = flatten_handle(frontend_handle);
// if everything is working, these should all run forever
let mut exited_with_err = false;
let mut frontend_exited = false;
tokio::select! {
x = flatten_handles(spawned_app.app_handles) => {
match x {
Ok(_) => info!("app_handle exited"),
Err(e) => {
error!("app_handle exited: {:#?}", e);
exited_with_err = true;
}
}
}
x = frontend_handle => {
frontend_exited = true;
match x {
Ok(_) => info!("frontend exited"),
Err(e) => {
error!("frontend exited: {:#?}", e);
exited_with_err = true;
}
}
}
x = flatten_handle(prometheus_handle) => {
match x {
Ok(_) => info!("prometheus exited"),
Err(e) => {
error!("prometheus exited: {:#?}", e);
exited_with_err = true;
}
}
}
x = tokio::signal::ctrl_c() => {
// TODO: unix terminate signal, too
match x {
Ok(_) => info!("quiting from ctrl-c"),
Err(e) => {
// TODO: i don't think this is possible
error!("error quiting from ctrl-c: {:#?}", e);
exited_with_err = true;
}
}
}
// TODO: This seems to have been removed on the main branch
// TODO: how can we properly watch background handles here? this returns None immediatly and the app exits. i think the bug is somewhere else though
x = spawned_app.background_handles.next() => {
match x {
Some(Ok(_)) => info!("quiting from background handles"),
Some(Err(e)) => {
error!("quiting from background handle error: {:#?}", e);
exited_with_err = true;
}
None => {
// TODO: is this an error?
warn!("background handles exited");
}
}
}
};
// TODO: This is also not there on the main branch
// if a future above completed, make sure the frontend knows to start turning off
if !frontend_exited {
if let Err(err) = frontend_shutdown_sender.send(()) {
// TODO: this is actually expected if the frontend is already shut down
warn!(?err, "shutdown sender");
};
}
// TODO: Also not there on main branch
// TODO: wait until the frontend completes
if let Err(err) = frontend_shutdown_complete_receiver.recv().await {
warn!(?err, "shutdown completition");
} else {
info!("frontend exited gracefully");
}
// now that the frontend is complete, tell all the other futures to finish
if let Err(err) = app_shutdown_sender.send(()) {
warn!(?err, "backend sender");
};
info!(
"waiting on {} important background tasks",
spawned_app.background_handles.len()
);
let mut background_errors = 0;
while let Some(x) = spawned_app.background_handles.next().await {
match x {
Err(e) => {
error!("{:?}", e);
background_errors += 1;
}
Ok(Err(e)) => {
error!("{:?}", e);
background_errors += 1;
}
Ok(Ok(_)) => {
// TODO: how can we know which handle exited?
trace!("a background handle exited");
continue;
}
}
}
if background_errors.is_zero() && !exited_with_err {
info!("finished");
Ok(())
} else {
// TODO: collect all the errors here instead?
Err(anyhow::anyhow!("finished with errors!"))
}
}
}