Struct Policy 

pub struct Policy {
    pub request_local: Option<bool>,
    pub coalesce: Option<bool>,
    pub local_ttl_sec: Option<u64>,
    pub remote_ttl_sec: Option<u64>,
    pub local_ramp: Option<f64>,
    pub remote_ramp: Option<f64>,
    pub stale_on_error_max_age_sec: Option<u64>,
    pub remote_read_timeout_ms: Option<u64>,
    pub shadow: Option<ShadowPolicy>,
}

Static caching policy of one operation. Omitted leaves use library defaults or are overridden by a runtime overlay.

Fields

request_local: Option<bool>

Memoize values for the outermost enabled scope. Defaults to false.

coalesce: Option<bool>

Share one execution across concurrent same-key callers. Defaults to true.

local_ttl_sec: Option<u64>

Process-local TTL in whole seconds, 1..=MAX_CACHE_TTL_SEC. Omitted disables the layer.

remote_ttl_sec: Option<u64>

Remote TTL in whole seconds. Omitted disables the layer.

local_ramp: Option<f64>

Local serving cohort percentage; a configured TTL implies 100.

remote_ramp: Option<f64>

Remote serving cohort percentage; a configured TTL implies 100.

stale_on_error_max_age_sec: Option<u64>

Exclusive stale-recovery age ceiling in seconds; must exceed the remote TTL. Zero disables.

remote_read_timeout_ms: Option<u64>

Remote read budget in milliseconds, 1..=MAX_DEADLINE_MS.

shadow: Option<ShadowPolicy>

Shadow validation cohort and warning policy. Omitted means no shadow work.

Implementations

impl Policy

pub fn enabled(ttl_sec: u64) -> Self

Both serving layers enabled with the same TTL and full ramps.

pub fn disabled() -> Self

The explicit kill switch: request memoization, recovery and shadow work off, both serving layers ramped to zero. As an overlay it disables every inherited path instead of relying on omission.

pub fn request_local(self, enabled: bool) -> Self

Set whether values are memoized for the outermost enabled scope.

pub fn coalesce(self, enabled: bool) -> Self

Set whether concurrent same-key callers share one execution.

pub fn local_ttl_sec(self, ttl_sec: u64) -> Self

Set the process-local TTL in whole seconds, enabling the layer with an implied full ramp.

pub fn remote_ttl_sec(self, ttl_sec: u64) -> Self

Set the remote TTL in whole seconds, enabling the layer with an implied full ramp.

pub fn local_ramp(self, ramp: f64) -> Self

Set the process-local serving cohort percentage, 0.0..=100.0.

pub fn remote_ramp(self, ramp: f64) -> Self

Set the remote serving cohort percentage, 0.0..=100.0.

pub fn stale_on_error_max_age_sec(self, seconds: u64) -> Self

Set the stale-recovery age ceiling in seconds. Zero disables recovery; a positive value must exceed the remote TTL.

pub fn remote_read_timeout_ms(self, ms: u64) -> Self

Set the remote read budget in milliseconds, overriding the instance default.

pub fn shadow(self, shadow: ShadowPolicy) -> Self

Set the shadow validation policy.

pub fn from_json(value: &Value) -> Result<Policy, PolicyError>

Parse the JSON-shaped TypeScript configuration (ttlSec, ramp, shadow, requestLocal, coalesce, staleOnErrorMaxAgeSec, remoteReadTimeoutMs). null or absent means an empty policy.

A present leaf holding null is an invalid supplied value, not an omission: JSON has no way to spell JavaScript’s undefined, so every member of an object counts as present.

pub fn to_json(&self) -> Value

The JSON-shaped form of this policy, with omitted leaves absent.

ttlSec and ramp are always objects (possibly empty). All other leaves, including requestLocal and coalesce, appear only when set, so converting this policy to a runtime overlay preserves inheritance.

pub fn validate(&self) -> Result<(), PolicyError>

Reject statically invalid leaves.

Trait Implementations

impl Clone for Policy

fn clone(&self) -> Policy

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Policy

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

Formats the value using the given formatter.

impl Default for Policy

fn default() -> Policy

Returns the “default value” for a type.

impl From<Policy> for RuntimePolicy

fn from(policy: Policy) -> Self

Converts to this type from the input type.

impl PartialEq for Policy

fn eq(&self, other: &Policy) -> 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 StructuralPartialEq for Policy