Crate slokit 

slokit

An SLO and error-budget engine for Rust.

slokit does two things:

1. Library core (always available): compute error budgets, burn rates, and the multi-window multi-burn-rate (MWMBR) alert model from the Google SRE Workbook. This core has no serde, YAML, or CLI dependencies, so it embeds cleanly inside services (for example, an Axum handler that reports live budget status).

2. Generator (the spec feature, on by default via cli): parse a sloth-compatible YAML spec and generate Prometheus recording rules, metadata rules, and MWMBR page/ticket alert rules.

Library example

use slokit::{Objective, Slo, BurnRate, Window};

let slo = Slo::new(Objective::percent(99.9).unwrap(), Window::days(30));

// With a million events, 0.1% may fail: ~1,000 allowed failures.
let budget = slo.error_budget(1_000_000.0);
assert!((budget.allowed_bad_events() - 1_000.0).abs() < 1e-6);

// Observing a 1% error rate is a 10x burn against a 99.9% objective.
let burn = BurnRate::from_error_ratio(0.01, &slo);
assert!((burn.value() - 10.0).abs() < 1e-9);

Generating Prometheus rules

With the default features enabled:

use slokit::spec::Spec;
use slokit::generate::generate_rules;

let spec = Spec::from_yaml(yaml_str)?;
let ruleset = generate_rules(&spec)?;
println!("{}", ruleset.to_yaml()?);

Re-exports

pub use error::Result;

pub use error::SlokitError;

Modules

checkcheck

Live checking against a Prometheus HTTP API.

dashboarddashboard

Generate a Grafana dashboard from a Spec.

error

Error type for the slokit crate.

generatespec

Generate Prometheus rules from a Spec.

specspec

The slokit SLO spec: a sloth-compatible YAML model plus small native extensions.

Structs

AlertWindow

One burn-rate condition: a long and short window that must both be burning faster than factor times the budget for the alert to fire.

BurnRate

How fast an error budget is being consumed.

ErrorBudget

A concrete error budget: the allowable failures for a known event volume over an SLO period.

MwmbrConfig

A multi-window multi-burn-rate alert configuration: the set of burn-rate conditions that, OR-ed together per severity, form the page and ticket alerts.

Objective

A reliability target, stored as a ratio in the open interval (0, 1).

Slo

A Service Level Objective: an Objective measured over a rolling Window (the SLO period, typically 30 days).

Window

A non-zero span of time, stored as whole seconds.

Enums

Severity

Alert severity in the MWMBR scheme.

Sli

How an SLO’s error ratio is computed from Prometheus.

Constants

WINDOW_TOKEN

The template token replaced with each lookback window when rendering queries. Matches sloth’s Go-template convention.