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latency.go
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latency.go
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package main
import (
"github.com/gorilla/mux"
"math/rand"
"net/http"
"strconv"
"time"
)
type LatencyInjector func()
func NewNoLatencyInjector() LatencyInjector {
return func() {}
}
func NewStaticLatencyInjector(waitforms int64) LatencyInjector {
return func() {
time.Sleep(time.Millisecond * time.Duration(waitforms))
}
}
func NewNormalLatencyInjector(seed int64, minms, medianms, maxms float64) LatencyInjector {
r := rand.New(rand.NewSource(seed))
leftdev := (medianms - minms) / 2.328
rightdev := (maxms - medianms) / 2.328
return func() {
norm := r.NormFloat64()
var sleepms float64
if norm < 0 {
randval := norm*leftdev + medianms
if randval < minms {
sleepms = minms
} else {
sleepms = randval
}
} else {
randval := norm*rightdev + medianms
if randval > maxms {
sleepms = maxms
} else {
sleepms = randval
}
}
time.Sleep(time.Duration(float64(time.Millisecond) * sleepms))
}
}
// /timeout/{timeout:[0-9]+}
// /timeout/{min:[0-9]+},{median:[0-9]+},{max:[0-9]+}
// An endpoint that will wait the specified amount of time before returning 200
// Can take a single value or a 3 values to form a normal distribution
func (api *MockApi) TimeoutHandler(rw http.ResponseWriter, req *http.Request) {
vars := mux.Vars(req)
timeoutStr, timeoutOk := vars["timeout"]
if !timeoutOk {
minStr, minOk := vars["min"]
medianStr, medianOk := vars["median"]
maxStr, maxOk := vars["max"]
if !minOk || !medianOk || !maxOk {
rw.WriteHeader(http.StatusBadRequest)
} else {
min, _ := strconv.ParseFloat(minStr, 64)
median, _ := strconv.ParseFloat(medianStr, 64)
max, _ := strconv.ParseFloat(maxStr, 64)
NewNormalLatencyInjector(time.Now().UTC().UnixNano(), min, median, max)()
}
} else {
timeout, _ := strconv.ParseInt(timeoutStr, 10, 64)
NewStaticLatencyInjector(timeout)()
rw.WriteHeader(http.StatusOK)
}
}