Enum BackendFailureMode 

pub enum BackendFailureMode {
    L1Only,
    Error,
    Retry {
        attempts: u8,
    },
}

Behaviour when an L2 backend operation fails.

Defaults to BackendFailureMode::L1Only — the most permissive mode, suitable for caches that are an optimisation rather than a correctness boundary. Consumers with stricter consistency requirements should pick BackendFailureMode::Error (propagate) or BackendFailureMode::Retry (retry-with-backoff before falling through). The policy applies to operations that actually touch the backend: insert, get_async, and invalidate. Fetch and refresh helpers apply fetched values to the in-process L1 map and do not write those values through to L2.

Variants

L1Only

Log the backend error, fall back to L1-only. Insert / get / invalidate succeed against L1 even if the backend is unreachable. The recommended default.

Error

Propagate the backend error to the caller. insert returns Err(InsertError::BackendFailed(...)), get_async and invalidate return Err(BackendError). Use when those backend-touching operations should treat L2 as a correctness requirement, not an optimisation.

Retry

Retry the backend operation up to attempts total attempts (including the original call) before falling through to L1Only behaviour for retryable errors. Backoff uses an internal capped exponential schedule plus 0-25% jitter in production call paths. attempts must be at least 1.

Fields

attempts: u8

Number of attempts before giving up.

Trait Implementations

impl Clone for BackendFailureMode

fn clone(&self) -> BackendFailureMode

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for BackendFailureMode

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl PartialEq for BackendFailureMode

fn eq(&self, other: &BackendFailureMode) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Copy for BackendFailureMode

impl Eq for BackendFailureMode

impl StructuralPartialEq for BackendFailureMode