Struct NestedSupervisorBuilder 

pub struct NestedSupervisorBuilder<'a, S = Restartable> { /* private fields */ }

Builder for a yet-to-be-started nested supervisor.

The counterpart to ChildBuilder for a child that is itself a Supervisor, and deliberately a much smaller surface. A nested supervisor has no placement of its own (it runs wherever its parent does, and its children carry their own placement) and no shutdown deadline of its own (it bounds its own drain through its children), so what is left to configure is the restart policy and significance.

Uses the same typestate as ChildBuilder: significance is offered only once the restart policy has been narrowed to one that lets the child terminate for good, since a permanent child is always brought back and so never has a termination for the parent to act on.

Implementations

impl<'a, S: BuilderState> NestedSupervisorBuilder<'a, S>

pub fn build(self) -> ChildSpecification<SupervisorSpec>

Finishes describing the child without starting it, for Supervisor::add_worker.

Use this to register a configured subtree on a supervisor that hasn’t started yet; spawn is the counterpart for a supervisor that is already running.

Whichever supervisor this builder was created against is irrelevant here – the child belongs to whichever one it is handed to.

pub fn spawn(self) -> ChildId

Spawns the nested supervisor.

Returns the child’s ChildId. As with ChildBuilder::spawn, the child is queued rather than started synchronously.

Panics

If this builder targets the ambient supervisor and there isn’t one, this panics. See spawn.

impl<'a> NestedSupervisorBuilder<'a, Restartable>

pub fn transient(self) -> NestedSupervisorBuilder<'a, Terminable>

Restarts this subtree only when it terminates abnormally.

Narrows the restart policy to RestartType::Transient, which makes with_significant available.

pub fn temporary(self) -> NestedSupervisorBuilder<'a, Terminable>

Never restarts this subtree.

Narrows the restart policy to RestartType::Temporary, which makes with_significant available.

impl<S: CanTerminate> NestedSupervisorBuilder<'_, S>

pub fn with_significant(self, significant: bool) -> Self

Sets whether this subtree’s termination should stop the parent supervisor.

See ChildBuilder::with_significant, which this mirrors.