Simulate slow HTTP server.

main.go

package main

import (
	"flag"
	"fmt"
	"log"
	"math/rand"
	"net"
	"os"
	"strings"
	"time"
)

const DEFAULT_BODY = `HTTP/1.1 %s OK
X-elastic-product: Fake Elasticsearch
content-type: application/json; charset=UTF-8
content-length: 21

{"acknowledged":true}`

const (
	CONN_HOST = "localhost"
	CONN_TYPE = "tcp"
)

var port = flag.Uint("port", 9200, "port to listen on")
var responseDelay = flag.Int("responseDelay", 10, "how many seconds to wait before responding")
var statusCodes = flag.String("statuses", "200", "comma separated list of HTTP response codes to potentially reply with")

// hit this server with curl -X POST --data "whatever" --connect-timeout 1 http://localhost:9200

func main() {
	flag.Parse()
	address := fmt.Sprint(CONN_HOST, ":", *port)
	statuses := strings.Split(*statusCodes, ",")
	l, err := net.Listen(CONN_TYPE, address)
	if err != nil {
		log.Println("Error listening:", err.Error())
		os.Exit(1)
	}
	defer l.Close()
	log.Println("Listening on " + address)
	for {
		// Listen for an incoming connection.
		conn, err := l.Accept()
		if err != nil {
			log.Println("Error accepting: ", err.Error())
			os.Exit(1)
		}
		// Actually serve the request
		status := statuses[rand.Intn(len(statuses))]
		go handleRequest(conn, status)
	}
}

// Handles incoming requests.
func handleRequest(conn net.Conn, status string) {
	reqID := rand.Int63()
	log.Printf("Received request %d", reqID)
	buf := make([]byte, 1024)
	_, err := conn.Read(buf)
	if err != nil {
		log.Println("Error reading:", err.Error())
	}
	// Delay a response
	time.Sleep(time.Duration(*responseDelay) * time.Second)
	conn.Write([]byte(fmt.Sprintf(DEFAULT_BODY, status)))
	conn.Close()
	log.Printf("Sent %s response for %d", status, reqID)
}