Struct Slots 

pub struct Slots { /* private fields */ }

A bound on how many runs may be live at once, with a queue for the rest.

Implementations

impl Slots

pub fn new(capacity: usize) -> Self

Creates a flight line with capacity slots.

A capacity of zero is treated as one. A factory that cannot start anything is not a safer factory, it is a broken one, and the configuration is checked separately.

pub fn capacity(&self) -> usize

How many runs may be live at once.

pub fn live(&self) -> usize

How many are live now.

pub fn waiting(&self) -> usize

How many are waiting.

pub fn is_full(&self) -> bool

Returns true when every slot is taken.

pub fn is_live(&self, run: &RunId) -> bool

Returns true when this run is currently occupying a slot.

pub fn request(&mut self, run: RunId) -> Admission

Asks for a slot.

Asking twice for the same run is not an error and does not take a second slot: the Tower may retry, and a rail that leaked a slot per retry would throttle itself to a standstill without anything looking wrong.

pub fn release(&mut self, run: &RunId) -> Option<RunId>

Gives a slot back, returning whichever queued run may now start.

Releasing a run that was only queued withdraws it instead — a run cancelled while waiting must not take a slot it no longer needs.

pub fn queue(&self) -> impl Iterator<Item = &RunId>

Everything waiting, in the order it will start.

Trait Implementations

impl Clone for Slots

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Slots

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

Formats the value using the given formatter.