/
barrier.go
74 lines (57 loc) · 1.34 KB
/
barrier.go
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package rpc
import (
"fmt"
)
type Barrier interface {
Acquire()
Release()
BusyCount() int
Capacity() int
CapacityInfo() string
Exhausted()
HasDynamicCapacity() bool
Start()
Stop()
}
type FixedSizeBarrier struct {
capacity int
capacityInfo string
sem chan (struct{})
}
var _ Barrier = (*FixedSizeBarrier)(nil)
func NewFixedSizeBarrier(capacity int) (*FixedSizeBarrier, error) {
if capacity <= 0 {
return nil, fmt.Errorf("RPC concurrency must be > 0")
}
sem := make(chan struct{}, capacity)
for i := 0; i < capacity; i++ {
sem <- struct{}{}
}
return &FixedSizeBarrier{
capacity: capacity,
capacityInfo: fmt.Sprintf("%d", capacity),
sem: sem,
}, nil
}
func (b *FixedSizeBarrier) Acquire() {
<-b.sem
}
func (b *FixedSizeBarrier) Release() {
b.sem <- struct{}{}
}
func (b *FixedSizeBarrier) BusyCount() int {
// The number of in-flight request is the
// the number of initial capacity "tickets" (concurrency)
// minus the size of the semaphore channel
return b.capacity - len(b.sem)
}
func (b *FixedSizeBarrier) Capacity() int {
return b.capacity
}
func (b *FixedSizeBarrier) CapacityInfo() string {
return b.capacityInfo
}
func (FixedSizeBarrier) Exhausted() {}
func (FixedSizeBarrier) HasDynamicCapacity() (res bool) { return }
func (FixedSizeBarrier) Start() {}
func (FixedSizeBarrier) Stop() {}