Struct RestartTracker 

pub struct RestartTracker {
    pub restart_count: u32,
    pub window_start: Instant,
    pub last_restart: Option<Instant>,
    pub backoff_ms: u64,
}

Restart state tracking per supervised agent.

Fields

restart_count: u32

Number of restarts in the current window.

window_start: Instant

When the current budget window started.

last_restart: Option<Instant>

When the last restart occurred.

backoff_ms: u64

Current backoff delay in milliseconds (exponential: 100ms -> 30s max).

Implementations

impl RestartTracker

pub fn new() -> Self

Create a new tracker with the window starting now.

pub fn next_backoff_ms(&self) -> u64

Calculate the next backoff delay in milliseconds.

Exponential backoff: 100ms * 2^(restart_count - 1), capped at 30s.

Preserved as the hardcoded fallback. See Self::next_backoff_ms_with_model for the EML-aware variant used by the supervisor. The fallback remains reachable so callers without a model (and every existing test) behave identically.

pub fn next_backoff_ms_with_model( &self, model: Option<&RestartStrategyModel>, failure_type: u32, uptime_secs: f64, system_load: f64, ) -> u64

Calculate the next backoff delay, consulting an optional RestartStrategyModel.

When model is None or untrained, this returns the same exponential-backoff value as Self::next_backoff_ms (the model’s predict falls back to the identical formula when !is_trained). When trained, the model’s learned delay is used instead.

failure_type is the error-kind ordinal (0 = unknown / default when the caller doesn’t track failure kinds), uptime_secs is the agent uptime before the failure, and system_load is a normalised 0.0-1.0 load signal.

NOTE(eml-swap): wired — Finding #5 (RestartStrategyModel).

pub fn check_window(&mut self, budget: &RestartBudget)

Check if the restart budget window has expired and reset if so.

pub fn record_restart(&mut self, budget: &RestartBudget) -> bool

Record a restart attempt. Returns true if within budget, false if budget exceeded.

pub fn record_restart_with_model( &mut self, budget: &RestartBudget, model: Option<&RestartStrategyModel>, failure_type: u32, uptime_secs: f64, system_load: f64, ) -> bool

Record a restart attempt with an optional learned RestartStrategyModel.

Behaviour is identical to Self::record_restart when model is None or untrained; when trained, the computed backoff_ms is sourced from the model.

NOTE(eml-swap): wired — Finding #5 (RestartStrategyModel).

pub fn is_exhausted(&self, budget: &RestartBudget) -> bool

Check whether the restart budget is exhausted.

pub fn remaining(&self, budget: &RestartBudget) -> u32

Number of restarts remaining in the current window.

Returns 0 if the budget is already exhausted. Returns max_restarts if the window has expired (it would reset on the next record_restart).

pub fn should_restart(strategy: &RestartStrategy, exit_code: i32) -> bool

Determine whether a process should be restarted based on the strategy and exit code.

Trait Implementations

impl Default for RestartTracker

Available on crate feature os-patterns only.

fn default() -> Self

Returns the “default value” for a type.