Struct TailCutLayerBuilder

pub struct TailCutLayerBuilder { /* private fields */ }

Builder for TailCutLayer.

Use this to configure the layer, then call build() to create a layer that can be cloned and shared across multiple operators.

Examples

use opendal::layers::TailCutLayer;
use std::time::Duration;

let layer = TailCutLayer::builder()
    .percentile(95)
    .window(Duration::from_secs(60))
    .build();

let op = Operator::new(services::Memory::default())?
    .layer(layer)
    .finish();

Implementations

impl TailCutLayerBuilder

pub fn new() -> Self

Create a new builder with default settings.

pub fn percentile(self, percentile: u8) -> Self

Set the percentile threshold (e.g., 95 for P95, 99 for P99).

Requests slower than this percentile × safety_factor will be cancelled.

Default: 95

Panics

Panics if percentile is not between 50 and 99.

pub fn safety_factor(self, factor: f64) -> Self

Set the safety factor multiplier.

The actual deadline is calculated as: P{percentile} × safety_factor. A higher value reduces false positives but may miss some long tails.

Default: 1.3 (30% buffer)

Panics

Panics if factor is not between 1.0 and 5.0.

pub fn window(self, window: Duration) -> Self

Set the sliding window duration for statistics collection.

Longer windows provide more stable statistics but react slower to changes. Shorter windows adapt faster but may be more noisy.

Default: 60 seconds

Panics

Panics if window is greater than 120 seconds.

pub fn min_samples(self, min_samples: usize) -> Self

Set the minimum number of samples required before enabling adaptive cancellation.

During cold start (when sample count < min_samples), the layer will not cancel any requests to avoid false positives.

Default: 200

pub fn min_deadline(self, deadline: Duration) -> Self

Set the minimum deadline (floor).

Even if calculated deadline is shorter, it will be clamped to this value. This prevents overly aggressive cancellation on very fast backends.

Default: 500ms

pub fn max_deadline(self, deadline: Duration) -> Self

Set the maximum deadline (ceiling).

Even if calculated deadline is longer, it will be clamped to this value. This acts as a safety fallback timeout.

Default: 30s

pub fn build(self) -> TailCutLayer

Build the layer.

The returned layer can be cloned to share statistics across operators.

Examples

use opendal::layers::TailCutLayer;
use std::time::Duration;

let layer = TailCutLayer::builder()
    .percentile(95)
    .window(Duration::from_secs(60))
    .build();

// Share the layer across operators
let op1 = Operator::new(services::Memory::default())?
    .layer(layer.clone())
    .finish();

let op2 = Operator::new(services::Memory::default())?
    .layer(layer.clone())
    .finish();
// op1 and op2 share the same statistics

Trait Implementations

impl Clone for TailCutLayerBuilder

fn clone(&self) -> TailCutLayerBuilder

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Default for TailCutLayerBuilder

fn default() -> Self

Returns the “default value” for a type.