simple upload file to s3 ด้วย golang

s3.go

package main

import (
	"bytes"
	"encoding/json"
	"fmt"
	"io"
	"log"
	"net/http"

	"github.com/aws/aws-sdk-go/aws"
	"github.com/aws/aws-sdk-go/aws/credentials"
	"github.com/aws/aws-sdk-go/aws/session"
	"github.com/aws/aws-sdk-go/service/s3"
	"github.com/aws/aws-sdk-go/service/s3/s3manager"
	"github.com/gorilla/mux"
)

const (
	AWS_S3_REGION = "<REGION>"
	AWS_S3_BUCKET = "<BUCKET>"
)

var sess = connectAWS()

func connectAWS() *session.Session {
	sess, err := session.NewSession(&aws.Config{
		Region:      aws.String(AWS_S3_REGION),
    Credentials: credentials.NewStaticCredentials(<AWSAccessKeyId>, <AWSSecretKey>, ""),
	})
	if err != nil {
		panic(err)
	}
	return sess
}

//  simple
func uploadFile(w http.ResponseWriter, r *http.Request) {
	fmt.Printf("====Upload File ===")
	file, header, err := r.FormFile("file")
	if err != nil {
		fmt.Println("Error ", err)
		return
	}
	defer file.Close()
	filename := header.Filename

	uploader := s3manager.NewUploader(sess)
	_, err = uploader.Upload(&s3manager.UploadInput{
		Bucket: aws.String(AWS_S3_BUCKET), // Bucket
		Key:    aws.String(filename),      // Name of the file to be saved
		Body:   file,                      // File
	})
	if err != nil {
		log.Println("Something went wrong uploading the file", err)
		return
	}
	data := map[string]string{
		"msg": "Successfully uploaded to " + AWS_S3_BUCKET,
	}

	json.NewEncoder(w).Encode(&data)
}

func getFile(w http.ResponseWriter, r *http.Request) {
	vars := mux.Vars(r)
	filename := vars["file"]
	results, err := s3.New(sess).GetObject(&s3.GetObjectInput{
		Bucket: aws.String(AWS_S3_BUCKET),
		Key:    aws.String(filename),
	})
	if err != nil {
		log.Println("", err)
		return
	}
	defer results.Body.Close()

	buf := bytes.NewBuffer(nil)
	if _, err := io.Copy(buf, results.Body); err != nil {
		log.Println("", err)
		return
	}
	w.Header().Set("Content-type", "image/png")
	w.Write(buf.Bytes())
	return
}

func hello(w http.ResponseWriter, r *http.Request) {
	data := map[string]string{
		"msg": "Hello Golang",
	}

	json.NewEncoder(w).Encode(&data)
}

func setupRoutes() {
	r := mux.NewRouter()
	r.HandleFunc("/", hello).Methods(http.MethodGet)
	r.HandleFunc("/getfile/{file}", getFile).Methods(http.MethodGet)
	r.HandleFunc("/upload/", uploadFile).Methods(http.MethodPost)
	log.Println("listen port :1234")
	http.ListenAndServe(":1234", r)
}

func main() {
	setupRoutes()
}