Server having a period of freeze or extreme slowness. See https://youtu.be/lJ8ydIuPFeU?t=1274

slowdownserver.go

// Copyright 2019 Google LLC
// SPDX-License-Identifier: Apache-2.0
package main

import (
	"fmt"
	"log"
	"net/http"
	"sync"
	"time"
)

var mu sync.Mutex
var n int
var start time.Time

func main() {
	http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
		mu.Lock()
		n++
		if n == 1 {
			start = time.Now()
		}
		current := n
		mu.Unlock()

		log.Println("Processing", current)
		defer log.Println("Finished", current)

		fast := 50 * time.Millisecond
		factor := 1
		t := time.Since(start)
		if t > 5*time.Second && t < 10*time.Second {
			// Extremely slow period during 5s
			factor = 120

			// Somewhat slow period during 5s
			// factor = 5
		}
		processDuration := time.Duration(factor) * fast
		time.Sleep(processDuration)
		fmt.Fprintln(w, "ok", current)
	})
	http.ListenAndServe(":8080", nil)
}