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Index ¶
Constants ¶
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Variables ¶
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Functions ¶
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Types ¶
type AsyncPool ¶
type AsyncPool interface {
// Go mimics the semantics of the "go" keyword, with the only difference being the `ctx` parameter,
// which is used to cancel **the submission of task**.
// **All** tasks successfully submitted will be run eventually, as long as Run are called infinitely many times.
// Go might block when the AsyncPool is not running.
Go(ctx context.Context, f func()) error
// Run runs the AsyncPool.
Run(ctx context.Context) error
}
AsyncPool provides a simple Goroutine pool, where the order in which jobs are run is non-deterministic.
func NewDefaultAsyncPool ¶
NewDefaultAsyncPool creates a new AsyncPool that uses the default implementation
type EventHandle ¶
type EventHandle interface {
// AddEvent adds an `event` object to the internal queue, so that the `f` used to register the handle can be called.
// Note: events are always processed in the order they are added.
// Unregistering the EventHandle MAY CAUSE EVENT LOSSES. But for an event lost, any event after it is guaranteed to be lost too.
// Cancelling `ctx` here will cancel the on-going or next execution of the event.
AddEvent(ctx context.Context, event interface{}) error
// AddEvents is like AddEvent but retrieves a slice instead of an object.
AddEvents(ctx context.Context, events []interface{}) error
// SetTimer is used to provide a function that is periodic called, as long as the EventHandle has not been unregistered.
// The current implementation uses as the base clock source a ticker whose interval is the const workerPoolDefaultClockSourceInterval.
// DO NOT set an interval less than workerPoolDefaultClockSourceInterval.
// Cancelling `ctx` here will cancel the on-going or next execution of `f`.
SetTimer(ctx context.Context, interval time.Duration, f func(ctx context.Context) error) EventHandle
// Unregister removes the EventHandle from the WorkerPool.
// Note: Unregister WILL block until the operation has taken effect, i.e. the handler will not be executed after
// Unregister returns. Unregister WILL NOT attempt to wait for pending events to complete, which means the last few events can be lost.
Unregister()
// GracefulUnregister removes the EventHandle after
// all pending events have been processed.
GracefulUnregister(ctx context.Context, timeout time.Duration) error
// ErrCh returns a channel that outputs the first non-nil result of events submitted to this EventHandle.
// Note that a non-nil result of an event cancels the EventHandle, so there is at most one error.
ErrCh() <-chan error
// OnExit is used to provide a function that will be called when the handle exits abnormally.
OnExit(f func(err error)) EventHandle
}
EventHandle is a handle for a registered event. Since events are executed asynchronously, errors should be collected from ErrCh(). EventHandles SHOULD NOT be assumed to be thread safe.
type Hashable ¶
type Hashable interface {
HashCode() int64
}
Hashable is an object that can be hashed.
type Hasher ¶
Hasher is actually a "placement driver" that balances the workload. Non-trivial Hashers will be useful if and when we implement dynamic resizing of WorkerPool.
type WorkerPool ¶
type WorkerPool interface {
// RegisterEvent returns a handle that can be used to trigger the execution of `f`.
// `f` will be called with a context that is a child of the context with which Run is called.
// TODO more reasonable usage of contexts, potentially involving context merging.
RegisterEvent(f func(ctx context.Context, event interface{}) error) EventHandle
// Run runs the WorkerPool.
// Internally several Goroutines are spawned.
Run(ctx context.Context) error
}
WorkerPool runs a number of Goroutines that process the submitted events. Each EventHandle is bound to a fixed worker thread to prevent data races.
func NewDefaultWorkerPool ¶
func NewDefaultWorkerPool(numWorkers int) WorkerPool
NewDefaultWorkerPool creates a new WorkerPool that uses the default implementation
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