Struct TaskContext 

pub struct TaskContext { /* private fields */ }

The context for a task, which can be used to cancel the task or spawn sub-tasks.

Unlike WorkerContext, which is shared across all tasks, a TaskContext is unique to a single task and can be cloned to share with sub-tasks. A task context is considered “executed” when the task has successfully completed or has been cancelled, and all sub-tasks have also completed.

Implementations

impl TaskContext

pub fn cancel(&self) -> Result<(), TaskStateError>

Requests cancellation of the task.

Wakes any pending WaitForExecutionFuture futures waiting for execution to complete

Errors

Returns an error if the task had already reached a terminal state (already cancelled or already completed).

pub fn is_completed(&self) -> bool

Returns whether the task has been completed.

pub fn is_cancelled(&self) -> bool

Returns whether cancellation has been requested.

pub fn is_executed(&self) -> bool

Returns whether there is nothing left to wait on:

If true the task has either completed or been cancelled.

pub fn executed(&self) -> WaitForExecutionFuture

Returns a future that resolves once the task is executed — either completed or cancelled.

Can be awaited standalone or raced against other futures, e.g.:

futures_util::select! {
    _ = ctx.executed().fuse() => { /* task done */ }
    res = some_work.fuse() => { /* completed with `res` */ }
}

pub fn elapsed(&self) -> Duration

Returns how long the task has been running.

pub fn task_id(&self) -> &str

Returns the task id for this token.

pub fn execution_context(&self) -> Option<Arc<ExecutionContext>>

Recovers the execution context for the task, if it’s still available.

Returns None once the owning ExecutionContext has been dropped.

pub fn len(&self) -> usize

Returns the number of sub-tasks currently spawned by this task context.

pub fn is_empty(&self) -> bool

Returns whether there are any subtasks running.

pub fn run_until_executed<F>(&self, fut: F) -> SubTaskFuture<F>

where F: Future,

Spawns a (sub-task) future that is tied to this task context.

Runs a future to completion, returning its result unless this TaskContext is completed first.

Biased towards completion: if the future resolves and the task is completed in the same poll, the future’s result wins.

Trait Implementations

impl Borrow<str> for TaskContext

fn borrow(&self) -> &str

Immutably borrows from an owned value.

impl Clone for TaskContext

fn clone(&self) -> TaskContext

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for TaskContext

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

Formats the value using the given formatter.

impl Eq for TaskContext

impl<Args: Sync> FromRequest<Task<Args>> for TaskContext

type Error = MissingDataError

The error type that can occur during extraction.

async fn from_request(task: &Task<Args>) -> Result<Self, Self::Error>

Perform the extraction.

impl Hash for TaskContext

fn hash<H: Hasher>(&self, state: &mut H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq for TaskContext

fn eq(&self, other: &Self) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.