Struct hydroflow::scheduled::context::Context

pub struct Context { /* private fields */ }

The main state of the Hydroflow instance, which is provided as a reference to each operator as it is run.

As an optimization, each Hydroflow instances stores eactly one Context inline, which allows us to avoid any construction/deconstruction costs. Before the Context is provided to a running operator, the subgraph_id field must be updated.

Implementations

impl Context

Public APIs.

pub fn current_tick(&self) -> TickInstant

Gets the current tick (local time) count.

pub fn current_tick_start(&self) -> SystemTime

Gets the timestamp of the beginning of the current tick.

pub fn is_first_run_this_tick(&self) -> bool

Gets whether this is the first time this subgraph is being scheduled for this tick

pub fn current_stratum(&self) -> usize

Gets the current stratum nubmer.

pub fn current_subgraph(&self) -> SubgraphId

Gets the ID of the current subgraph.

pub fn schedule_subgraph(&self, sg_id: SubgraphId, is_external: bool)

Schedules a subgraph.

pub fn waker(&self) -> Waker

Returns a Waker for interacting with async Rust. Waker events are considered to be extenral.

pub fn state_ref<T>(&self, handle: StateHandle<T>) -> &T

where T: Any,

Returns a shared reference to the state.

pub fn state_mut<T>(&mut self, handle: StateHandle<T>) -> &mut T

where T: Any,

Returns an exclusive reference to the state.

pub fn add_state<T>(&mut self, state: T) -> StateHandle<T>

where T: Any,

Adds state to the context and returns the handle.

pub fn set_state_tick_hook<T>( &mut self, handle: StateHandle<T>, tick_hook_fn: impl 'static + FnMut(&mut T), )

where T: Any,

Sets a hook to modify the state at the end of each tick, using the supplied closure.

pub fn remove_state<T>(&mut self, handle: StateHandle<T>) -> Box<T>

where T: Any,

Removes state from the context returns it as an owned heap value.

pub fn request_task<Fut>(&mut self, future: Fut)

where Fut: Future<Output = ()> + 'static,

Prepares an async task to be launched by Self::spawn_tasks.

pub fn spawn_tasks(&mut self)

Launches all tasks requested with Self::request_task on the internal Tokio executor.

pub fn abort_tasks(&mut self)

Aborts all tasks spawned with Self::spawn_tasks.

pub async fn join_tasks(&mut self)

Waits for all tasks spawned with Self::spawn_tasks to complete.

Will probably just hang.