Struct RateLimitConfig 

pub struct RateLimitConfig {
    pub respect_retry_after: bool,
    pub default_delay: Duration,
    pub max_delay: Duration,
    pub requests_per_minute: u32,
    pub fallback_after_retries: u32,
    pub max_retries: u32,
}

Policy for handling 429 / 503 rate-limit responses from LLM providers.

Governs backoff and retry behaviour when the server signals that the client should slow down: a 429 Too Many Requests, a 503 Service Unavailable, or a 529 Overloaded. All three can carry a Retry-After hint that this config can honour.

Distinct from StreamRetryConfig, which covers generic stream-initialization transport failures (the connection itself failed to open).

Example

use loopctl::stream::handler::RateLimitConfig;
use std::time::Duration;

let cfg = RateLimitConfig {
    default_delay: Duration::from_secs(2),
    fallback_after_retries: 2,
    ..Default::default()
};
assert!(cfg.validate().is_ok());

Fields

respect_retry_after: bool

Whether to honour a 429/503 Retry-After value when the server provides one.

When true (the default), backoff returns the server-advised delay (capped at max_delay). When false, the server’s hint is ignored and default_delay is always used.

default_delay: Duration

Backoff used when the server gives no Retry-After.

Also used unconditionally when respect_retry_after is false. Defaults to 5s — long enough to let a transient burst clear, short enough that a missing header doesn’t stall the agent.

max_delay: Duration

Upper bound on any single rate-limit backoff.

Caps both the server’s Retry-After (when honoured) and default_delay so a misbehaving provider cannot stall the agent indefinitely.

requests_per_minute: u32

Advisory per-minute request ceiling for proactive throttling (0 = unset).

This field is not read at runtime by the reactive rate-limit handler — it does not throttle on its own. It is the value a caller feeds to RateLimiter::new when attaching a proactive limiter via StreamHandler::with_rate_limiter. Zero (the default) means no proactive throttling is configured; reactive handling of server-returned 429/503 responses is unaffected and governed by the other fields below.

fallback_after_retries: u32

Number of rate-limit retries before switching to a fallback model.

After this many retries on the same model, the next rate limit triggers a fallback to a different model (if one is configured).

max_retries: u32

Hard cap on rate-limit retries for a single turn.

Once this many retries have been exhausted, the turn fails outright. Distinct from fallback_after_retries, which controls the escalation threshold to a fallback model, not the hard stop after which the turn gives up entirely.

Implementations

impl RateLimitConfig

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

Validate the policy.

default_delay and max_delay must be non-zero, max_delay must be at least default_delay, and max_retries must be at least 1.

Errors

Returns a human-readable description of the first violated constraint.

use loopctl::stream::handler::RateLimitConfig;
use std::time::Duration;

assert!(RateLimitConfig::default().validate().is_ok());
let bad = RateLimitConfig { max_retries: 0, ..Default::default() };
assert!(bad.validate().is_err());

pub fn backoff(&self, server_hint: Option<Duration>) -> Duration

Effective backoff for a detected rate limit given an optional server hint.

• If server_hint is Some(d) and respect_retry_after is true, returns min(d, max_delay).
• Otherwise returns min(default_delay, max_delay).

use loopctl::stream::handler::RateLimitConfig;
use std::time::Duration;

let cfg = RateLimitConfig::default();
assert_eq!(cfg.backoff(Some(Duration::from_secs(12))), Duration::from_secs(12));
assert_eq!(cfg.backoff(None), cfg.default_delay);

Trait Implementations

impl Clone for RateLimitConfig

fn clone(&self) -> RateLimitConfig

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for RateLimitConfig

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

Formats the value using the given formatter.

impl Default for RateLimitConfig

fn default() -> Self

Returns the “default value” for a type.