Struct ServiceContext

pub struct ServiceContext<'a> { /* private fields */ }

An interface to the service provided to the tasks during initialization. This the main point of interaction between with the service.

The context provides access to the runtime, resources, and allows adding new tasks.

Implementations

impl<'a> ServiceContext<'a>

pub fn runtime_handle(&self) -> &Handle

Provides access to the runtime used by the service.

Can be used to spawn additional tasks within the same runtime. If some task stores the handle to spawn additional tasks, it is expected to do all the required cleanup.

In most cases, however, it is recommended to use add_task or its alternative instead.

Note

While tokio::spawn and tokio::spawn_blocking will work as well, using the runtime handle from the context is still a recommended way to get access to runtime, as it tracks the access to the runtimes by layers.

pub fn add_task<T: Task>(&mut self, task: T) -> &mut Self

Adds a task to the service.

Added tasks will be launched after the wiring process will be finished and all the preconditions are met.

pub fn add_shutdown_hook(&mut self, hook: ShutdownHook) -> &mut Self

Adds a future to be invoked after node shutdown. May be used to perform cleanup tasks.

The future is guaranteed to only be polled after all the node tasks are stopped or timed out. All the futures will be awaited sequentially.

pub fn get_resource<T: Resource + Clone>(&mut self) -> Result<T, WiringError>

Attempts to retrieve the resource of the specified type.

Panics

Panics if the resource with the specified ResourceId exists, but is not of the requested type.

pub fn get_resource_or_insert_with<T: Resource + Clone, F: FnOnce() -> T>( &mut self, f: F, ) -> T

Attempts to retrieve the resource of the specified type. If the resource is not available, it is created using the provided closure.

pub fn get_resource_or_default<T: Resource + Clone + Default>(&mut self) -> T

Attempts to retrieve the resource of the specified type. If the resource is not available, it is created using T::default().

pub fn insert_resource<T: Resource>( &mut self, resource: T, ) -> Result<(), WiringError>

Adds a resource to the service.

If the resource with the same type is already provided, the method will return an error.

Trait Implementations

impl<'a> Debug for ServiceContext<'a>

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

Formats the value using the given formatter.