File size: 11,799 Bytes
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//!
//! Ordinary recovery tries to resume the same executor session after a transient
//! disconnect. Replacement needs a fresh session, without waiting for old recovery
//! to give up. The caller supplies the ordering: register the replacement first,
//! then refresh. Executor identity stays inside this connection layer.
//!
//! Flow: fresh registry lookup -> reuse or retire session -> connect if needed ->
//! live status probe. The lazy client and its `Environment` remain the same objects;
//! only the underlying `ExecServerClient` may change. The public caller contract is on
//! `Environment::refresh_connection`.
//!
//! Two races determine the synchronization here. A client installed during the
//! lookup makes that lookup stale, so refresh checks again. A connection attempt
//! cancelled by refresh must never install later. Cancellation and installation
//! synchronize on the `current_client` lock; acquire `reconnect` first when both are needed.
//! `refresh_lock` serializes only explicit refreshes; ordinary connection and recovery
//! work can continue concurrently. Retired sessions cannot publish environment state.
use std::sync::Arc;
use std::sync::Mutex as StdMutex;
use futures::future::BoxFuture;
use tokio::sync::OnceCell;
use tokio::sync::watch;
use tokio::time::timeout;
use tokio_util::sync::CancellationToken;
use super::ConnectionResult;
use super::ConnectionStatus;
use super::ExecServerClient;
use super::ExecServerError;
use super::Inner;
use super::LazyRemoteExecServerClient;
use super::fail_all_in_flight_work;
use crate::EnvironmentConnectionState;
use crate::NoiseChannelPublicKey;
use crate::client_api::DEFAULT_REMOTE_EXEC_SERVER_CONNECT_TIMEOUT;
use crate::client_api::ExecServerTransportParams;
use crate::client_api::NoiseRendezvousConnectBundle;
use crate::client_api::NoiseRendezvousConnectProvider;
use crate::client_transport::ExecServerReconnectStrategy;
/// Shared startup/reconnect result plus cancellation for work superseded by refresh.
/// The optional transport carries a refresh lookup's bundle into the normal connector.
#[derive(Default)]
pub(super) struct ConnectionAttempt {
pub(super) result: OnceCell<ConnectionResult>,
pub(super) cancelled: CancellationToken,
pub(super) transport: Option<ExecServerTransportParams>,
}
// Use the compared bundle intact for the first connection: address, key and authorization
// belong together. Later lookups, including authorization refresh, use the real provider.
struct PrefetchedConnectProvider {
bundle: StdMutex<Option<NoiseRendezvousConnectBundle>>,
provider: Arc<dyn NoiseRendezvousConnectProvider>,
}
impl NoiseRendezvousConnectProvider for PrefetchedConnectProvider {
fn connect_bundle(
&self,
harness_public_key: NoiseChannelPublicKey,
) -> BoxFuture<'_, Result<NoiseRendezvousConnectBundle, ExecServerError>> {
Box::pin(async move {
let bundle = self
.bundle
.lock()
.unwrap_or_else(std::sync::PoisonError::into_inner)
.take();
match bundle {
Some(bundle) => Ok(bundle),
None => self.provider.connect_bundle(harness_public_key).await,
}
})
}
}
impl LazyRemoteExecServerClient {
#[expect(
clippy::await_holding_invalid_type,
reason = "serialize explicit refreshes, not ordinary connection or recovery attempts"
)]
pub(crate) async fn refresh_connection(&self) -> Result<(), ExecServerError> {
let _refresh = self.refresh_lock.lock().await;
let (previous, attempt) = loop {
let observed = self.cached_client();
let mut transport = self.transport_params.clone().ok_or_else(|| {
ExecServerError::Protocol(
"connection refresh requires a Noise registry".to_string(),
)
})?;
let target = match &mut transport {
ExecServerTransportParams::Deferred(deferred) => &mut deferred.transport,
transport => transport,
};
let ExecServerTransportParams::NoiseRendezvous { provider, identity } = target else {
return Err(ExecServerError::Protocol(
"connection refresh requires a Noise registry".to_string(),
));
};
// This lookup is independent of the old session and its recovery deadline.
let bundle = timeout(
DEFAULT_REMOTE_EXEC_SERVER_CONNECT_TIMEOUT,
provider.connect_bundle(identity.public_key()),
)
.await
.map_err(|_| {
ExecServerError::EnvironmentRegistryRequest(
codex_http_client::RouteAwareRequestError::Timeout,
)
})??;
let executor_public_key = bundle.executor_public_key.clone();
*provider = Arc::new(PrefetchedConnectProvider {
bundle: StdMutex::new(Some(bundle)),
provider: Arc::clone(provider),
});
let mut reconnect = self
.reconnect
.lock()
.unwrap_or_else(std::sync::PoisonError::into_inner);
let current = self
.current_client
.lock()
.unwrap_or_else(std::sync::PoisonError::into_inner);
// An ordinary connection may have finished during the lookup. Re-read the
// registry rather than retire a newer client using a superseded response.
if !match (&observed, &*current) {
(Some(observed), Some(current)) => Arc::ptr_eq(&observed.inner, ¤t.inner),
(None, None) => true,
_ => false,
} {
continue;
}
// is_disconnected means terminally failed, not temporarily recovering.
// Preserve same-executor recovery; the final probe fails fast if still recovering.
if current.as_ref().is_some_and(|client| {
!client.is_disconnected()
&& matches!(
client.inner.reconnect_strategy.as_ref(),
Some(ExecServerReconnectStrategy::NoiseRendezvous {
executor_public_key: key, ..
}) if key == &executor_public_key
)
}) {
break (current.clone(), None);
}
// Cancellation and connection installation use the same lock. A late
// handshake cannot install a client after its attempt has been superseded.
self.startup.cancelled.cancel();
if let Some(attempt) = reconnect.as_ref() {
attempt.cancelled.cancel();
}
self.environment_connection_state_tx
.send_replace(EnvironmentConnectionState::Disconnected);
let attempt = Arc::new(ConnectionAttempt {
transport: Some(transport),
..Default::default()
});
*reconnect = Some(Arc::clone(&attempt));
break (current.clone(), Some(attempt));
};
let client = match attempt {
Some(attempt) => {
if let Some(previous) = previous {
previous.inner.retire().await;
}
let result = attempt
.result
.get_or_init(|| self.connect_once(&attempt))
.await
.clone();
let mut reconnect = self
.reconnect
.lock()
.unwrap_or_else(std::sync::PoisonError::into_inner);
if reconnect
.as_ref()
.is_some_and(|current| Arc::ptr_eq(current, &attempt))
{
*reconnect = None;
}
result.map_err(ExecServerError::ConnectionAttempt)?
}
None => previous.ok_or_else(|| {
ExecServerError::Protocol("current executor session is missing".to_string())
})?,
};
// Metadata may be cached; readiness requires a live, non-recovering probe.
client.environment_status().await.map(drop)
}
#[tracing::instrument(name = "codex.exec_server.remote.connect", skip_all)]
pub(super) fn connect_once<'a>(
&'a self,
attempt: &'a ConnectionAttempt,
) -> BoxFuture<'a, ConnectionResult> {
// Keep the transport future out of every caller's async layout, including
// the CLI entry point, which otherwise exceeds rustc's query-depth limit.
Box::pin(async move {
let transport = attempt
.transport
.as_ref()
.or(self.transport_params.as_ref())
.ok_or_else(|| {
Arc::new(ExecServerError::Protocol(
"missing transport params for lazy exec-server connection".to_string(),
))
})?;
let client = tokio::select! {
biased;
_ = attempt.cancelled.cancelled() => return Err(Arc::new(ExecServerError::Disconnected("connection attempt was superseded".to_string()))),
result = ExecServerClient::connect_for_transport(transport.clone(), self.http_client_factory.clone()) => result.map_err(Arc::new)?,
};
// Cancellation can race with a completed handshake. Recheck before attaching
// state or installing the client, under the same lock used by refresh.
{
let mut current = self
.current_client
.lock()
.unwrap_or_else(std::sync::PoisonError::into_inner);
if !attempt.cancelled.is_cancelled() {
client.attach_environment_connection_state(
self.environment_connection_state_tx.clone(),
);
*current = Some(client.clone());
return Ok(client);
}
}
client.inner.retire().await;
Err(Arc::new(ExecServerError::Disconnected(
"connection attempt was superseded".to_string(),
)))
})
}
}
impl Inner {
async fn retire(self: &Arc<Self>) {
let message = "exec-server executor was replaced".to_string();
let rpc_client = {
let mut connection = self
.connection
.lock()
.unwrap_or_else(std::sync::PoisonError::into_inner);
// Detach before a later transport completion can publish stale state.
connection.environment_connection_state_tx =
watch::channel(EnvironmentConnectionState::Disconnected).0;
let rpc_client = match &connection.status {
ConnectionStatus::Connected(client) => Some(Arc::clone(client)),
ConnectionStatus::Recovering | ConnectionStatus::Failed(_) => None,
};
self.retired.cancel();
connection.set_status(ConnectionStatus::Failed(message.clone()));
rpc_client
};
self.connection_changed.send_replace(());
// Drain pending RPCs before stream cleanup, which may wait for other work.
if let Some(rpc_client) = rpc_client {
rpc_client.close_transport().await;
}
fail_all_in_flight_work(self, message).await;
}
}
#[cfg(test)]
#[path = "client_refresh_tests.rs"]
mod tests;
|