nautechsystems/nautilus_trader · error

ExecutionAlgorithmConfig must have exec_algorithm_id set

Error message

ExecutionAlgorithmConfig must have exec_algorithm_id set

What it means

ExecutionAlgorithmConfig::new panics via `expect` when the config has no `exec_algorithm_id`, because the algorithm cannot be constructed without an identifier. The type technically allows `None` (probably to satisfy a shared config struct), but this constructor requires it. It is an eager invariant check: fail fast at construction instead of deep inside the actor machinery.

Source

Thrown at crates/trading/src/algorithm/core.rs:145

            .field(
                "strategy_event_handlers",
                &self.strategy_event_handlers.len(),
            )
            .finish()
    }
}

impl ExecutionAlgorithmCore {
    /// Creates a new [`ExecutionAlgorithmCore`] instance.
    ///
    /// # Panics
    ///
    /// Panics if `config.exec_algorithm_id` is `None`.
    #[must_use]
    pub fn new(config: ExecutionAlgorithmConfig) -> Self {
        let exec_algorithm_id = config
            .exec_algorithm_id
            .expect("ExecutionAlgorithmConfig must have exec_algorithm_id set");

        let actor_config = DataActorConfig {
            actor_id: Some(ActorId::new(exec_algorithm_id.inner())),
            log_events: config.log_events,
            log_commands: config.log_commands,
        };

        Self {
            actor: DataActorCore::new(actor_config),
            config,
            exec_algorithm_id,
            exec_spawn_ids: AHashMap::new(),
            subscribed_strategies: AHashSet::new(),
            pending_spawn_reductions: AHashMap::new(),
            submit_params: AHashMap::new(),
            portfolio: None,
            strategy_event_handlers: IndexMap::new(),
        }

View on GitHub (pinned to 18893faf8b)

Solutions

1. Set `exec_algorithm_id: Some(ExecAlgorithmId::from("MY_ALGO"))` (or parse from string) before calling `new`.
2. Validate the config at load/deserialization time and reject it with a clear error before reaching this constructor.
3. Build the config from a fully-populated source (typed deserialization with required field) rather than partial defaults.
4. If the id truly cannot be known yet, defer construction until it is available instead of calling `new` with a placeholder-less config.

Example fix

// before
let config = ExecutionAlgorithmConfig {
    exec_algorithm_id: None,
    log_events: true,
    log_commands: true,
};
let algo = ExecutionAlgorithm::new(config); // panics

// after
let config = ExecutionAlgorithmConfig {
    exec_algorithm_id: Some(ExecAlgorithmId::from("EXEC_ALARM")),
    log_events: true,
    log_commands: true,
};
let algo = ExecutionAlgorithm::new(config);

// Rust
fn validate_exec_algorithm_config(config: &ExecutionAlgorithmConfig) -> Result<(), String> {
    if config.exec_algorithm_id.is_none() {
        return Err("exec_algorithm_id is required".to_string());
    }
    Ok(())
}
validate_exec_algorithm_config(&config)?;
let algo = ExecutionAlgorithm::new(config);

fn has_exec_algorithm_id(config: &ExecutionAlgorithmConfig) -> bool {
    config.exec_algorithm_id.is_some()
}

When it happens

Trigger: Calling `ExecutionAlgorithmConfig::new(config)` (or `ExecutionAlgorithm::new(config)`) where `config.exec_algorithm_id` is `None` — e.g. building the config programmatically from optional CLI/JSON fields, or deserializing a config file that omitted the `exec_algorithm_id` key.

Common situations: Loading a TOML/JSON execution algorithm config where the id field is optional and missing; constructing a default config before assigning an id; copying config-building code that sets logging flags but never the id; migrating code that used to infer the id elsewhere.

Understand the failure class

Background: "is required", "must be set", "missing required field": configuration validation errors across open-source libraries — this error's family across 36 libraries.

Related errors

• Invalid factory address for DEX {name} on chain {chain} for
• window limit must be non-zero
• `step` overflows raw quantity units for volume aggregation
• vega pricing timeout exceeds the nanosecond range
• default `StrategyConfig` should be valid

AI-assisted analysis of nautechsystems/nautilus_trader@18893faf8b (2026-09-08). Data as JSON: /api/errors/e45bd25d63241fdf. Report an issue: GitHub.