nautechsystems/nautilus_trader · error

errors.join("; ")

Error message

errors.join("; ")

What it means

During teardown of the Bybit data client, finish_tasks joins session and command tasks; any task that fails to finish is collected as a message. If any errors accumulated, the whole operation bails with all messages joined by "; ". This indicates background websocket/HTTP tasks did not shut down cleanly during connect/teardown.

Source

Thrown at crates/adapters/bybit/src/data.rs:264

        let (session_result, command_result) = tokio::join!(
            self.session_tasks
                .finish_shutdown(Duration::from_secs(1), Duration::from_secs(2)),
            self.command_tasks
                .finish_shutdown(Duration::from_secs(1), Duration::from_secs(2)),
        );
        let mut errors = Vec::new();
        if let Err(e) = session_result {
            errors.push(format!("failed to finish Bybit data session tasks: {e}"));
        }

        if let Err(e) = command_result {
            errors.push(format!("failed to finish Bybit data command tasks: {e}"));
        }

        if errors.is_empty() {
            Ok(())
        } else {
            anyhow::bail!(errors.join("; "))
        }
    }

    async fn prepare_task_groups(&mut self) -> anyhow::Result<()> {
        if !self.session_tasks.is_open() || !self.command_tasks.is_open() {
            self.teardown_partial_connect().await?;
            self.session_tasks
                .start_generation()
                .context("failed to start Bybit data session task generation")?;
            self.command_tasks
                .start_generation()
                .context("failed to start Bybit data command task generation")?;
            self.cancellation_token = self.session_tasks.cancellation_token();
        }
        Ok(())
    }

    fn spawn_ws<F>(&self, fut: F, context: &'static str)

View on GitHub (pinned to 18893faf8b)

Solutions

1. Read the joined messages to identify which tasks failed and the root cause
2. Check network/proxy stability and Bybit exchange status
3. Retry the connection after the failed teardown
4. If persistent, capture logs and file an issue with the specific task error

// before connect: check connectivity to Bybit endpoints
async fn bybit_reachable() -> bool { reqwest::get("https://api.bybit.com/v5/market/time").await.is_ok() }

match client.connect().await {
    Ok(()) => {},
    Err(e) => {
        log::error!("Bybit data connect/teardown failed: {e:#}");
        tokio::time::sleep(BACKOFF).await;
        retry_connect();
    }
}

When it happens

Trigger: Calling connect (via prepare_task_groups -> teardown_partial_connect) or disconnect when one or more spawned data command tasks returned an error like "failed to finish Bybit data command tasks: ...".

Common situations: Network drops mid-connect leaving tasks in a bad state; exchange websocket closing unexpectedly during startup/shutdown; partial connect failures where some tasks already errored.

Understand the failure class

Background: ECONNREFUSED and "connection refused" / "could not connect to server" errors: what they mean and how to fix them — this error's family across 44 libraries.

Related errors

• Bybit execution shutdown failed: {}
• Failed to terminate Bybit execution session tasks: {e}
• failed to finish Binance Futures data command tasks: {e}
• Binance Futures data teardown failed: {}
• Binance Futures shutdown failed: {}

AI-assisted analysis of nautechsystems/nautilus_trader@18893faf8b (2026-09-08). Data as JSON: /api/errors/246feeaa5a0003ac. Report an issue: GitHub.