nautechsystems/nautilus_trader · error · anyhow::Error

Invalid config type for BitmexDataClientFactory. Expected Bi

Error message

Invalid config type for BitmexDataClientFactory. Expected BitmexDataClientConfig, was {config:?}

What it means

BitmexDataClientFactory::create only accepts a config object that downcasts to BitmexDataClientConfig. Any other config type passed to the factory produces this error naming both the expected type and the actual config value.

Source

Thrown at crates/adapters/bitmex/src/factories.rs:89

impl Default for BitmexDataClientFactory {
    fn default() -> Self {
        Self::new()
    }
}

impl DataClientFactory for BitmexDataClientFactory {
    fn create(
        &self,
        name: &str,
        config: &dyn ClientConfig,
        _cache: CacheView,
        _clock: Rc<RefCell<dyn Clock>>,
    ) -> anyhow::Result<Box<dyn DataClient>> {
        let bitmex_config = config
            .as_any()
            .downcast_ref::<BitmexDataClientConfig>()
            .ok_or_else(|| {
                anyhow::anyhow!(
                    "Invalid config type for BitmexDataClientFactory. Expected BitmexDataClientConfig, was {config:?}",
                )
            })?
            .clone();

        let client_id = ClientId::from(name);
        let client = BitmexDataClient::new(client_id, bitmex_config)?;
        Ok(Box::new(client))
    }

    fn name(&self) -> &'static str {
        BITMEX
    }

    fn config_type(&self) -> &'static str {
        "BitmexDataClientConfig"
    }
}

View on GitHub (pinned to 18893faf8b)

Solutions

Pass a BitmexDataClientConfig instance to BitmexDataClientFactory::create.
Check the config section of your node/trading config maps to the data client, not the execution client.
Rebuild the config via the factory's expected type or a deserialization into BitmexDataClientConfig.
Compare the debug output in the message (was {config:?}) against the expected struct to spot the mismatch.

Example fix

// before
let config = BitmexExecutionClientConfig { ... };
let client = BitmexDataClientFactory.create(name, config, ...);
// after
let config = BitmexDataClientConfig { api_key, api_secret, ... };
let client = BitmexDataClientFactory.create(name, config, ...);

Defensive patterns

Strategy: type-guard

Validate before calling

// Rust
fn is_bitmex_data_config(config: &dyn Any) -> bool {
    config.downcast_ref::<BitmexDataClientConfig>().is_some()
}

Type guard

// Rust
fn as_bitmex_data_config(config: &dyn Any) -> Option<&BitmexDataClientConfig> {
    config.downcast_ref::<BitmexDataClientConfig>()
}

Try / catch

// Rust
let cfg = config.as_any()
    .downcast_ref::<BitmexDataClientConfig>()
    .ok_or_else(|| anyhow::anyhow!("expected BitmexDataClientConfig, got {:?}", config))?;

Prevention

Keep data vs execution client config sections separate in node configs
Rely on typed deserialization instead of hand-built configs
Double-check factory/config pairing when wiring adapters

When it happens

Trigger: Calling create on BitmexDataClientFactory with a config whose as_any().downcast_ref::<BitmexDataClientConfig>() returns None — e.g. passing BitmexExecutionClientConfig, a generic client config, or a config built for another venue.

Common situations: Registering the data client factory with the wrong config in a node config file, copy-pasting execution client config into the data client slot, or using a renamed/moved config struct after a version upgrade.

Related errors

AI-assisted analysis of nautechsystems/nautilus_trader@18893faf8b (2026-09-08). Data as JSON: /api/errors/d4c766a7f051dd32. Report an issue: GitHub.