/
generator.go
66 lines (52 loc) · 1.33 KB
/
generator.go
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package delay
import (
"math/rand"
"time"
)
// Generator provides an interface for generating wait times
type Generator interface {
NextWaitTime(time.Duration) time.Duration
}
var sharedRNG = rand.New(rand.NewSource(time.Now().UnixNano()))
// VariableNormalGenerator makes delays that following a normal distribution
func VariableNormalGenerator(std time.Duration, rng *rand.Rand) Generator {
if rng == nil {
rng = sharedRNG
}
return &variableNormal{
std: std,
rng: rng,
}
}
type variableNormal struct {
std time.Duration
rng *rand.Rand
}
func (d *variableNormal) NextWaitTime(t time.Duration) time.Duration {
return time.Duration(d.rng.NormFloat64()*float64(d.std)) + t
}
// VariableUniformGenerator generates delays following a uniform distribution
func VariableUniformGenerator(d time.Duration, rng *rand.Rand) Generator {
if rng == nil {
rng = sharedRNG
}
return &variableUniform{
d: d,
rng: rng,
}
}
type variableUniform struct {
d time.Duration // max delta
rng *rand.Rand
}
func (d *variableUniform) NextWaitTime(t time.Duration) time.Duration {
return time.Duration(d.rng.Float64()*float64(d.d)) + t
}
type fixed struct{}
// FixedGenerator returns a delay with fixed latency
func FixedGenerator() Generator {
return &fixed{}
}
func (d *fixed) NextWaitTime(t time.Duration) time.Duration {
return t
}