Struct InstanceCell 

pub struct InstanceCell { /* private fields */ }

InstanceCell contains all of the type-erased, shareable state of an instance. Specifically, InstanceCells form a supervision tree, and is used by ActorHandle to access the underlying instance.

InstanceCell is reference counted and cloneable.

Implementations

impl InstanceCell

pub fn actor_id(&self) -> &ActorId

The actor’s ID.

pub fn status(&self) -> &Receiver<ActorStatus>

The instance’s status observer.

pub fn supervision_event(&self) -> Option<ActorSupervisionEvent>

The supervision event stored when this actor failed. None for actors that stopped cleanly or are still running.

pub fn signal(&self, signal: Signal) -> Result<(), ActorError>

Send a signal to the actor.

pub fn send_supervision_event_or_crash( &self, child_cx: &impl Actor, event: ActorSupervisionEvent, )

Used by this actor’s children to send a supervision event to this actor. When it fails to send, we will crash the process. As part of the crash, all the procs and actors running on this process will be terminated forcefully.

Note that “let it crash” is the default behavior when a supervision event cannot be delivered upstream. It is the upstream’s responsibility to detect and handle crashes.

pub fn downgrade(&self) -> WeakInstanceCell

Downgrade this InstanceCell to a weak reference.

pub fn child_count(&self) -> usize

The number of children this instance has.

pub fn child_actor_ids(&self) -> Vec<ActorId>

Returns the ActorIds of this instance’s direct children.

pub fn recording(&self) -> &Recording

Access the flight recorder for this actor.

pub fn created_at(&self) -> SystemTime

When this actor was created.

pub fn num_processed_messages(&self) -> u64

The number of messages processed by this actor.

pub fn last_message_handler(&self) -> Option<HandlerInfo>

The last message handler invoked by this actor.

pub fn total_processing_time_us(&self) -> u64

Total time spent processing messages, in microseconds.

pub fn parent(&self) -> Option<InstanceCell>

Get parent instance cell, if it exists.

pub fn actor_type_name(&self) -> &str

The actor’s type name.

pub fn set_published_attrs(&self, attrs: Attrs)

Replace the published introspection attrs with a new bag.

pub fn merge_published_attr<T: AttrValue>(&self, key: Key<T>, value: T)

Set a single introspection attr, merging into the existing bag (or creating one if none exists).

pub fn published_attrs(&self) -> Option<Attrs>

Read the published introspection attrs, if any.

pub fn set_query_child_handler( &self, handler: impl Fn(&Reference) -> IntrospectResult + Send + Sync + 'static, )

Register a callback for resolving non-addressable children via IntrospectMessage::QueryChild.

The callback runs on the actor’s introspect task (a separate tokio task, not the actor’s message loop), so it must be Send + Sync and must not access actor-mutable state. Capture cloned Proc references, not &mut self.

pub fn query_child(&self, child_ref: &Reference) -> Option<IntrospectResult>

Invoke the registered QueryChild handler, if any.

pub fn is_system(&self) -> bool

Whether this actor is infrastructure/system.

pub fn store_terminated_snapshot(&self, payload: IntrospectResult)

Store a post-mortem snapshot for this actor in the proc’s terminated_snapshots map. Called by the introspect task just before exiting on terminal status.

Eviction policy when the retention cap is exceeded:

1. Evict cleanly-stopped actors first (no failure_info).
2. When only failed actors remain, evict the most recent (by occurred_at), preserving the earliest failures which are closest to the root cause.

pub fn traverse<F>(&self, f: &mut F)

where F: FnMut(&InstanceCell, usize),

Traverse the subtree rooted at this instance in pre-order. The callback receives each InstanceCell and its depth (root = 0). Children are visited in pid order for deterministic traversal.

Trait Implementations

impl Clone for InstanceCell

fn clone(&self) -> InstanceCell

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for InstanceCell

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

Formats the value using the given formatter.