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package main
import (
"flag"
"fmt"
"io/ioutil"
"log"
"math/rand"
"net/http"
"runtime"
"sync"
"time"
"gopkg.in/throttled/throttled.v1"
)
var (
numgc = flag.Int("gc", 0, "number of GC runs")
mallocs = flag.Int("mallocs", 0, "number of mallocs")
total = flag.Int("total", 0, "total number of bytes allocated")
allocs = flag.Int("allocs", 0, "number of bytes allocated")
refrate = flag.Duration("refresh", 0, "refresh rate of the memory stats")
delayRes = flag.Duration("delay-response", 0, "delay the response by a random duration between 0 and this value")
output = flag.String("output", "v", "type of output, one of `v`erbose, `q`uiet, `ok`-only, `ko`-only")
)
func main() {
flag.Parse()
var h http.Handler
var ok, ko int
var mu sync.Mutex
// Keep the start time to print since-time
start := time.Now()
// Create the thresholds struct
thresh := throttled.MemThresholds(&runtime.MemStats{
NumGC: uint32(*numgc),
Mallocs: uint64(*mallocs),
TotalAlloc: uint64(*total),
Alloc: uint64(*allocs),
})
if *output != "q" {
log.Printf("thresholds: NumGC: %d, Mallocs: %d, Alloc: %dKb, Total: %dKb", thresh.NumGC, thresh.Mallocs, thresh.Alloc/1024, thresh.TotalAlloc/1024)
}
// Create the MemStats throttler
t := throttled.MemStats(thresh, *refrate)
// Set its denied handler
t.DeniedHandler = http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
if *output == "v" || *output == "ko" {
log.Printf("KO: %s", time.Since(start))
}
throttled.DefaultDeniedHandler.ServeHTTP(w, r)
mu.Lock()
defer mu.Unlock()
ko++
})
// Throttle the OK handler
rand.Seed(time.Now().Unix())
h = t.Throttle(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
if *output == "v" || *output == "ok" {
log.Printf("ok: %s", time.Since(start))
}
if *delayRes > 0 {
wait := time.Duration(rand.Intn(int(*delayRes)))
time.Sleep(wait)
}
// Read the whole file in memory, to actually use 64Kb (instead of streaming to w)
b, err := ioutil.ReadFile("test-file")
if err != nil {
throttled.Error(w, r, err)
return
}
_, err = w.Write(b)
if err != nil {
throttled.Error(w, r, err)
}
mu.Lock()
defer mu.Unlock()
ok++
}))
// Print stats once in a while
go func() {
var mem runtime.MemStats
for _ = range time.Tick(10 * time.Second) {
mu.Lock()
runtime.ReadMemStats(&mem)
log.Printf("ok: %d, ko: %d", ok, ko)
log.Printf("TotalAllocs: %d Kb, Allocs: %d Kb, Mallocs: %d, NumGC: %d", mem.TotalAlloc/1024, mem.Alloc/1024, mem.Mallocs, mem.NumGC)
mu.Unlock()
}
}()
fmt.Println("server listening on port 9000")
http.ListenAndServe(":9000", h)
}
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