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