What causes "Unsupported hour step for Kraken Futures: {step}" in nautechsystems/nautilus_trader?

Change the hour step to 1, 4, or 12.

Unsupported hour step for Kraken Futures: {step}

Error message

Unsupported hour step for Kraken Futures: {step}

What it means

bar_type_to_futures_resolution cannot map the requested Hour-aggregation step for Kraken Futures; the futures resolution strings only cover 1h, 4h, and 12h, so any other hour step has no API resolution and the conversion fails.

Source

Thrown at crates/adapters/kraken/src/common/parse.rs:1205

/// # Errors
///
/// Returns an error if:
/// - Bar aggregation type is not supported.
/// - Bar step is not supported for the aggregation type.
pub fn bar_type_to_futures_resolution(bar_type: BarType) -> anyhow::Result<&'static str> {
    let step = bar_type.spec().step.get() as u32;
    match bar_type.spec().aggregation {
        BarAggregation::Minute => match step {
            1 => Ok("1m"),
            5 => Ok("5m"),
            15 => Ok("15m"),
            _ => anyhow::bail!("Unsupported minute step for Kraken Futures: {step}"),
        },
        BarAggregation::Hour => match step {
            1 => Ok("1h"),
            4 => Ok("4h"),
            12 => Ok("12h"),
            _ => anyhow::bail!("Unsupported hour step for Kraken Futures: {step}"),
        },
        BarAggregation::Day => {
            if step == 1 {
                Ok("1d")
            } else {
                anyhow::bail!("Unsupported day step for Kraken Futures: {step}")
            }
        }
        BarAggregation::Week => {
            if step == 1 {
                Ok("1w")
            } else {
                anyhow::bail!("Unsupported week step for Kraken Futures: {step}")
            }
        }
        other => {
            anyhow::bail!("Unsupported bar aggregation for Kraken Futures: {other:?}");
        }

View on GitHub (pinned to 18893faf8b)

Solutions

Change the hour step to 1, 4, or 12.
Request 1h bars and aggregate locally into 2h/6h/etc. bars.
Use Day aggregation (step 1) instead of 24h bars.

Example fix

// before
BarSpec::new(BarAggregation::Hour, 2)
// after
BarSpec::new(BarAggregation::Hour, 1) // aggregate to 2h locally

Defensive patterns

Strategy: validation

Validate before calling

const FUTURES_HOUR_STEPS: [u32; 3] = [1, 4, 12];
if bar_type.spec().aggregation == BarAggregation::Hour
    && !FUTURES_HOUR_STEPS.contains(&bar_type.spec().step.get() as u32) {
    eprintln!("Kraken Futures hour steps: 1, 4, 12");
}

Try / catch

match bar_type_to_futures_resolution(&bar_type) {
    Ok("1h") => {},
    Err(e) if e.to_string().contains("hour step") => switch_to_1h_and_aggregate(&bar_type)?,
    res => res?,
}

Prevention

Do not copy hour steps from other exchanges (2h/6h/8h) into Kraken Futures configs.
Centralize a per-venue bar-spec whitelist.
Aggregate 1h bars locally for unsupported intervals.

When it happens

Trigger: bar_type_to_futures_resolution receives BarAggregation::Hour with step not in {1, 4, 12} — e.g. 2h, 6h, or 24h bars.

Common situations: Bar specs copied from venues supporting arbitrary hour steps (e.g. Binance 2h/8h); multi-venue strategies not per-venue specializing bar specs.

Understand the failure class

Background: Invalid enum value errors: "Unknown type", "Invalid scope", "must be one of" — when a string is not on the library's allowed list — this error's family across 23 libraries.

Related errors

AI-assisted analysis of nautechsystems/nautilus_trader@18893faf8b (2026-09-08). Data as JSON: /api/errors/59c83de8c18eebbb. Report an issue: GitHub.