Struct Tasks 

pub struct Tasks { /* private fields */ }

A named task set for supervising concurrently-running Tokio tasks.

Dropping a task set aborts all tasks that are still running.

Implementations

impl Tasks

pub fn new() -> Self

Creates an empty task set.

pub fn spawn( &mut self, name: impl Into<String>, task: impl Future<Output = Result<()>> + Send + 'static, ) -> Id

Spawns a named task into the set.

pub fn spawn_infallible( &mut self, name: impl Into<String>, task: impl Future<Output = ()> + Send + 'static, ) -> Id

Spawns a named task that does not return an error.

pub async fn join_next( &mut self, ) -> Option<(String, Result<Result<()>, JoinError>)>

Waits for the next task to complete.

pub fn is_empty(&self) -> bool

Returns true if no tasks are currently in the set.

pub fn len(&self) -> usize

Returns the number of tasks currently in the set.

pub async fn join_next_as_error(&mut self) -> Result<()>

Waits for the next task to complete, treating that completion as an error.

This is intended for supervised task sets where every task is expected to run indefinitely.

pub async fn join_next_or_cancelled( &mut self, token: CancellationToken, ) -> Result<()>

Waits for either an unexpected task completion or a shutdown request.

Before shutdown, any task completion is treated as fatal because this type supervises long-running tasks. Such a completion triggers the shutdown itself: the token is cancelled and the remaining tasks are drained before the error is returned. Returning without draining would drop the set and abort the surviving tasks mid-work — e.g. the store’s block writer between its database commit and tree update, tearing persistent state.

Once token is cancelled (whether externally or by a failure here), clean task exits are accepted and this method waits for all tracked tasks to finish. The first failure observed is returned as the root cause; subsequent failures are logged, since they are often knock-on effects of the first.

Trait Implementations

impl Default for Tasks

fn default() -> Self

Returns the “default value” for a type.