je_load_density.utils.reliability.failure_budget

Sliding-window failure budget / circuit breaker.

Subscribes to Locust’s events.request and tracks the proportion of failed requests in a rolling window. Once the failure rate exceeds the threshold and the window has enough samples, the next request fires runner.quit() and raises CircuitOpenError on the main greenlet.

Functions

`current_budget`()
`install_failure_budget`([threshold, ...])	Subscribe to Locust request events; trip the breaker when the sliding-window failure rate exceeds `threshold`.
`uninstall_failure_budget`()

Classes

FailureBudget(threshold, window_seconds, ...)

Exceptions

CircuitOpenError

Raised when the failure budget trips.

exception je_load_density.utils.reliability.failure_budget.CircuitOpenError

Bases: RuntimeError

Raised when the failure budget trips.

class je_load_density.utils.reliability.failure_budget.FailureBudget(threshold: float = 0.05, window_seconds: float = 30.0, min_samples: int = 50, _events: Deque[tuple] = <factory>, _lock: <built-in function allocate_lock> = <factory>, _tripped: bool = False)

Bases: object

failure_rate(now: float | None = None) → float

is_breached(now: float | None = None) → bool

min_samples: int = 50

record(failed: bool, now: float | None = None) → None

sample_count() → int

threshold: float = 0.05

trip() → None

property tripped: bool

window_seconds: float = 30.0

je_load_density.utils.reliability.failure_budget.current_budget() → FailureBudget | None

je_load_density.utils.reliability.failure_budget.install_failure_budget(threshold: float = 0.05, window_seconds: float = 30.0, min_samples: int = 50, runner_quit_callback: Callable[[], None] | None = None) → FailureBudget: Subscribe to Locust request events; trip the breaker when the sliding-window failure rate exceeds threshold. The supplied runner_quit_callback is invoked once on breach.

je_load_density.utils.reliability.failure_budget.uninstall_failure_budget() → None