group_options.go

package syncs

import "context"

type options struct {
	ctx           context.Context
	preLock       bool
	termOnError   bool
	discardIfFull bool
	tresholdSize  int
}

// GroupOption functional option type
type GroupOption func(o *options)

// Context passes ctx to group, goroutines will be canceled if ctx is canceled
func Context(ctx context.Context) GroupOption {
	return func(o *options) {
		o.ctx = ctx
	}
}

// Preemptive sets locking mode preventing spawning waiting goroutine. May cause Go call to block!
func Preemptive(o *options) {
	o.preLock = true
}

// TermOnErr prevents new goroutines to start after first error
func TermOnErr(o *options) {
	o.termOnError = true
}

// Discard will discard new goroutines if semaphore is full, i.e. no more goroutines allowed
func Discard(o *options) {
	o.discardIfFull = true
	o.preLock = true // discard implies preemptive
}

// DiscardAfterTreshold works similarly to Discard, but buffers tasks if all goroutines are busy
// until the treshold size of 'active' tasks (i.e. executing and scheduled for execution) is achieved
// If this value is lower than size, it will be ignored and common Discard mode will is used
func DiscardAfterTreshold(tresholdSize int) GroupOption {
	return func(o *options) {
		o.discardIfFull = true
		o.preLock = true

		if tresholdSize < 1 {
			tresholdSize = 0
		}
		o.tresholdSize = tresholdSize
	}
}