Documentation
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Index ¶
- func Map[T any, M any](original Refreshable[T], mapFn func(T) M) (Refreshable[M], UnsubscribeFunc)
- func MapWithError[T any, M any](original Refreshable[T], mapFn func(T) (M, error)) (Validated[M], UnsubscribeFunc, error)
- func NewFromTickerFunc[T any](ctx context.Context, interval time.Duration, ...) (Ready[T], UnsubscribeFunc)
- func Validate[T any](original Refreshable[T], validatingFn func(T) error) (Validated[T], UnsubscribeFunc, error)
- func Wait[T any](ctx context.Context, ready Ready[T]) (T, bool)
- type Ready
- type Refreshable
- type UnsubscribeFunc
- type Updatable
- type Validated
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func Map ¶
func Map[T any, M any](original Refreshable[T], mapFn func(T) M) (Refreshable[M], UnsubscribeFunc)
Map returns a new Refreshable based on the current one that handles updates based on the current Refreshable.
func MapWithError ¶
func MapWithError[T any, M any](original Refreshable[T], mapFn func(T) (M, error)) (Validated[M], UnsubscribeFunc, error)
MapWithError is similar to Validate but allows for the function to return a mapping/mutation of the input object in addition to returning an error. The returned validRefreshable will contain the mapped value. An error is returned if the current original value fails to map.
func NewFromTickerFunc ¶
func NewFromTickerFunc[T any](ctx context.Context, interval time.Duration, provider func(ctx context.Context) (T, bool)) (Ready[T], UnsubscribeFunc)
NewFromTickerFunc returns a Ready Refreshable populated by the result of the provider called each interval. If the providers bool return is false, the value is ignored. The result's ReadyC channel is closed when a new value is populated. The refreshable will stop updating when the provided context is cancelled or the returned UnsubscribeFunc func is called.
func Validate ¶
func Validate[T any](original Refreshable[T], validatingFn func(T) error) (Validated[T], UnsubscribeFunc, error)
Validate returns a new Refreshable that returns the latest original value accepted by the validatingFn. If the upstream value results in an error, it is reported by Validation(). An error is returned if the current original value is invalid.
Types ¶
type Ready ¶
type Ready[T any] interface { Refreshable[T] // ReadyC returns a channel which is closed after a value is successfully populated. ReadyC() <-chan struct{} }
Ready extends Refreshable for asynchronous implementations which may not have a value when they are constructed. Callers should check that the Ready channel is closed before using the Current value.
func NewFromChannel ¶
NewFromChannel populates an Updatable with the values channel. If an element is already available, the returned Value is guaranteed to be populated. The channel should be closed when no longer used to avoid leaking resources.
type Refreshable ¶
type Refreshable[T any] interface { // Current returns the most recent value of this Refreshable. // If the value has not been initialized, returns T's zero value. Current() T // Subscribe calls the consumer function when Value updates until stop is closed. // The consumer must be relatively fast: Updatable.Set blocks until all subscribers have returned. // Expensive or error-prone responses to refreshed values should be asynchronous. // Updates considered no-ops by reflect.DeepEqual may be skipped. // When called, consumer is executed with the Current value. Subscribe(consumer func(T)) UnsubscribeFunc }
A Refreshable is a generic container type for a volatile underlying value. It supports atomic access and user-provided callback "subscriptions" on updates.
func MapContext ¶
func MapContext[T any, M any](ctx context.Context, original Refreshable[T], mapFn func(T) M) Refreshable[M]
MapContext is like Map but unsubscribes when the context is cancelled.
type UnsubscribeFunc ¶
type UnsubscribeFunc func()
UnsubscribeFunc removes a subscription from a refreshable's internal tracking and/or stops its update routine. It is safe to call multiple times.
type Updatable ¶
type Updatable[T any] interface { Refreshable[T] // Update updates the Refreshable with a new T. // It blocks until all subscribers have completed. Update(T) }
A Updatable is a Refreshable which supports setting the value with a user-provided value. When a utility returns a (non-Updatable) Refreshable, it implies that value updates are handled internally.
type Validated ¶
type Validated[T any] interface { Refreshable[T] // Validation returns the result of the most recent validation. // If the last value was valid, Validation returns the same value as Current and a nil error. // If the last value was invalid, it and the error are returned. Current returns the most recent valid value. Validation() (T, error) }
A Validated is a Refreshable capable of rejecting updates according to validation logic. Its Current method returns the most recent value to pass validation.
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