[Go MSA with Docker Swarm] 02-First Go Microservice

Part 2에서는

• Go Workspace 구축
• 첫번째 Microservice 개발 : HTTP 서버

Introduction

HTTP 기반하여 JSON으로 통신하는 방법이 서비스 간의 유일한 방식은 아니지만 이 블로그 시리즈에서는 HTTP와 JSON을 사용하겠습니다.

사실 많은 유용한 프레임워크 (security, tracing)들은 HTTP 헤더에 의존합니다. grpc같은 다른 방법들도 존재하지만 구현에 집중하기 위해 HTTP로 진행하겠습니다.

Go Workspace 구축

mkdir $GOPATH/src/github.com/callistaenterprise
cd $GOPATH/src/github.com/callistaenterprise
mkdir -p goblog/accountservice
cd goblog/accountservice
touch main.go
mkdir service

/service/routes.go

package service

import "net/http"

// Defines a single route, e.g. a human readable name, HTTP method and the
// pattern the function that will execute when the route is called.
type Route struct {
    Name        string
    Method      string
    Pattern     string
    HandlerFunc http.HandlerFunc
}

// Defines the type Routes which is just an array (slice) of Route structs.
type Routes []Route

// Initialize our routes
var routes = Routes{

    Route{
        "GetAccount",                                     // Name
        "GET",                                            // HTTP method
        "/accounts/{accountId}",                          // Route pattern
        func(w http.ResponseWriter, r *http.Request) {
            w.Header().Set("Content-Type", "application/json; charset=UTF-8")
            w.Write([]byte("{\"result\":\"OK\"}"))
        },
    },
}

/service/router.go

package service

import (
    "github.com/gorilla/mux"
)

// Function that returns a pointer to a mux.Router we can use as a handler.
func NewRouter() *mux.Router {

    // Create an instance of the Gorilla router
    router := mux.NewRouter().StrictSlash(true)

    // Iterate over the routes we declared in routes.go and attach them to the router instance
    for _, route := range routes {

        // Attach each route, uses a Builder-like pattern to set each route up.
        router.Methods(route.Method).
            Path(route.Pattern).
            Name(route.Name).
            Handler(route.HandlerFunc)
    }
    return router
}

/service/webserver.go

package service

import (
    "log"
    "net/http"
)

func StartWebServer(port string) {

    r := NewRouter()
    http.Handle("/", r)

    log.Println("Starting HTTP service at " + port)
    err := http.ListenAndServe(":" + port, nil)    // Goroutine will block here

    if err != nil {
        log.Println("An error occured starting HTTP listener at port " + port)
        log.Println("Error: " + err.Error())
    }

}

main.go

package main

import (
    "fmt"
    "github.com/callistaenterprise/goblog/accountservice/service"
)

var appName = "accountservice"

func main() {
    fmt.Printf("Starting %v\n", appName)
    service.StartWebServer("6767")
}

> go get
> go run *.go
Starting accountservice
2017/01/31 15:15:57 Starting HTTP service at 6767
...
> curl http://localhost:6767/accounts/10000
  {"result":"OK"}

Performance

Apache Maven + JRE가 설치되있다고 가정합니다.

mkdir /globlog/loadtest
cd /globlog/loadtest
> mvn gatling:execute -Dusers=1000 -Dduration=30 -DbaseUrl=http://localhost:6767

• users : 테스트 유저 수
• duration : 테스트가 진행되는 시간 (s)
• baseUrl : docker swarm에서는 ip로 변경

완료가 되면 /target/gatlkng/result/에 html 결과가 나옵니다

• 테스트 전 : 1.2MB

  

• 1000개 유저 부하 테스트 후 : 28MB이지만 스프링 부트가 시작될 때 사용하는 메모리의 1/10정도 됩니다

  

• CPU Core : 8% on single core