Do a POST request every n milliseconds. Supports concurrent in-flight requests. Usage: `go run main.go`

config.json

{
  "requestFrequencyInMS": 100,
  "url": "http://localhost/",
  "cookies": {
    "key1": "value1",
    "key2": "value2"
  }
}

main.go

package main

import (
	"encoding/json"
	"fmt"
	"io/ioutil"
	"log"
	"net/http"
	"time"
)

const configFile = "config.json"

type config struct {
	RequestFrequencyInMS int
	URL                  string
	Cookies              map[string]string
}

func main() {
	file, err := ioutil.ReadFile(configFile)
	if err != nil {
		log.Fatal("failed to open config file: ", err)
	}

	c := &config{}
	err = json.Unmarshal([]byte(file), &c)
	if err != nil {
		log.Fatal("failed to unmarshal config file: ", err)
	}

	logger := make(chan string, 100)

	req, err := http.NewRequest("POST", c.URL, nil)
	if err != nil {
		log.Fatal("failed to create request: ", err)
	}
	for k, v := range c.Cookies {
		req.AddCookie(&http.Cookie{Name: k, Value: v})
	}

	for {
		select {
		case <-time.Tick(time.Duration(c.RequestFrequencyInMS) * time.Millisecond):
			go doRequest(req, logger)
		case msg := <-logger:
			log.Println(msg)
		}
	}
}

func doRequest(req *http.Request, logger chan string) {
	resp, err := http.DefaultClient.Do(req)
	if err != nil {
		logger <- fmt.Sprintf("request failed: %s", err)
		return
	}
	defer resp.Body.Close()

	logger <- resp.Status
}