openai/codex · error · std::io::Error

app-server control socket is already in use at {}

Error message

app-server control socket is already in use at {}

What it means

Error "app-server control socket is already in use at {}" thrown in openai/codex.

Source

Thrown at codex-rs/app-server-transport/src/transport/unix_socket.rs:100

                    warn!("failed to upgrade control socket websocket connection: {err}");
                    return;
                }
            };
            let (websocket_writer, websocket_reader) = websocket_stream.split();
            run_websocket_connection(websocket_writer, websocket_reader, transport_event_tx).await;
        });
    }
    info!("control socket acceptor shutting down");
}

pub async fn prepare_control_socket_path(socket_path: &Path) -> IoResult<()> {
    if let Some(parent) = socket_path.parent() {
        codex_uds::prepare_private_socket_directory(parent).await?;
    }

    match UnixStream::connect(socket_path).await {
        Ok(_stream) => {
            return Err(std::io::Error::new(
                ErrorKind::AddrInUse,
                format!(
                    "app-server control socket is already in use at {}",
                    socket_path.display()
                ),
            ));
        }
        Err(err) if err.kind() == ErrorKind::NotFound => return Ok(()),
        Err(err) if err.kind() == ErrorKind::ConnectionRefused => {}
        Err(err) => {
            if !socket_path.exists() {
                return Ok(());
            }
            return Err(err);
        }
    }

    if !socket_path.try_exists()? {

View on GitHub (pinned to 339751715c)

When it happens

Trigger: Thrown at codex-rs/app-server-transport/src/transport/unix_socket.rs:100 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of openai/codex@339751715c (2026-08-25). Data as JSON: /api/errors/13bea25eae8fd666. Report an issue: GitHub.