linera-io/linera-protocol · error

a running notification server

Error message

a running notification server

What it means

start_notification_server (linera-exporter/src/exporter_service.rs) serves the gRPC NotifierServiceServer on the configured endpoint with serve_with_shutdown and expects success. The expect fires when tonic fails to serve the endpoint - overwhelmingly a bind failure such as 'address already in use', plus invalid endpoint addresses or socket permission errors. This runs during exporter startup, so the process aborts before serving notifications.

Solutions

1. Find and stop the process holding the port: `ss -ltnp | grep <port>` or `lsof -i :<port>`, then kill it.
2. Change the notification port in the exporter config to a free one.
3. Verify the endpoint address format in the config (e.g. 0.0.0.0:PORT or 127.0.0.1:PORT).
4. If two exporters are intended, give each its own notification port.

// Before starting the exporter, verify the notification port is free:
let probe = tokio::net::TcpListener::bind(notification_endpoint).await;
match probe {
    Ok(l) => drop(l), // port free; brief TOCTOU window is acceptable at startup
    Err(e) if e.kind() == std::io::ErrorKind::AddrInUse => {
        return Err(anyhow::anyhow!("notification port already in use: {notification_endpoint}"));
    }
    Err(e) => return Err(e.into()),
}

When it happens

Trigger: Starting linera-exporter when the notification server port (from the config's notification section) is already bound by another process - a second exporter instance, a validator proxy using the same port, or a leftover process. Also a malformed endpoint address in the config.

Common situations: Duplicate exporter instances in a container/k8s setup pointing at the same port; port collision between the exporter's notification server and another service; stale process still holding the port after a crash.

Related errors

• a successful running of the server
• Exporter URI should be valid
• Failed to bind to address
• Failed to clone storage
• Failed to create log file

AI-assisted analysis of linera-io/linera-protocol@6c226ddcb3 (2026-08-22). Data as JSON: /api/errors/98a4b678bb544e34. Report an issue: GitHub.

Appendix: source

Thrown at linera-exporter/src/exporter_service.rs:96

        cancellation_token: CancellationToken,
    ) -> core::result::Result<(), ExporterError> {
        let endpoint = get_address(port);
        info!(
            "Starting linera_exporter_service on endpoint = {}",
            endpoint
        );

        let (health_reporter, health_service) = tonic_health::server::health_reporter();
        health_reporter
            .set_serving::<NotifierServiceServer<Self>>()
            .await;

        Server::builder()
            .add_service(health_service)
            .add_service(NotifierServiceServer::new(self))
            .serve_with_shutdown(endpoint, cancellation_token.cancelled_owned())
            .await
            .expect("a running notification server");

        Ok(())
    }
}

fn parse_notification(notification: Notification) -> core::result::Result<BlockId, ExporterError> {
    let chain_id = notification
        .chain_id
        .ok_or(BadNotificationKind::InvalidChainId { inner: None })?
        .try_into()
        .map_err(|err| BadNotificationKind::InvalidChainId { inner: Some(err) })?;

    let reason = bincode::deserialize::<Reason>(&notification.reason)
        .map_err(|err| BadNotificationKind::InvalidReason { inner: Some(err) })?;

    if let Reason::NewBlock { height, hash } = reason {
        return Ok(BlockId::new(chain_id, hash, height));
    }

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