go-async-http.go

package main

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

type PizzaOrder struct {
    Pizza, Store, Price string
}

func main() {

    var pizza = flag.String("pizza", "", "Pizza to order")
    var store = flag.String("store", "", "Name of the Pizza Store")
    var price = flag.String("price", "", "Price")

    flag.Parse()

    order := PizzaOrder{*pizza, *store, *price}
    body, _ := json.Marshal(order)

    start := time.Now()

    orderChan := make(chan *http.Response)
    paymentChan := make(chan *http.Response)
    storeChan := make(chan *http.Response)

    // OrderService is expected at 8081
    go SendPostAsync("http://localhost:8081", body, orderChan)

    // PaymentService is expected at 8082
    go SendPostAsync("http://localhost:8082", body, paymentChan)

    // StoreService is expected at 8083
    go SendPostAsync("http://localhost:8083", body, storeChan)

    orderResponse := <-orderChan
    defer orderResponse.Body.Close()
    bytes, _ := ioutil.ReadAll(orderResponse.Body)
    fmt.Println(string(bytes))

    paymentResponse := <-paymentChan
    defer paymentResponse.Body.Close()
    bytes, _ = ioutil.ReadAll(paymentResponse.Body)
    fmt.Println(string(bytes))

    storeResponse := <-storeChan
    defer storeResponse.Body.Close()
    bytes, _ = ioutil.ReadAll(storeResponse.Body)
    fmt.Println(string(bytes))

    end := time.Now()

    fmt.Printf("Order processed after %v seconds\n", end.Sub(start).Seconds())
}

func SendPostAsync(url string, body []byte, rc chan *http.Response) {
    response, err := http.Post(url, "application/json", bytes.NewReader(body))
    if err != nil {
        panic(err)
    }

    rc <- response
}

func SendPostRequest(url string, body []byte) *http.Response {
    response, err := http.Post(url, "application/json", bytes.NewReader(body))
    if err != nil {
        panic(err)
    }

    return response
}