Example on how to create a signed URL on Google Cloud Storage with Go

glcoud-signed-url.go

package main

import (
	"fmt"
	"time"

	"google.golang.org/cloud/storage"
)

const (
	projectID = "myProject-1234"
)

func main() {

	bucket := "mybucket"
	filename := "myFilename"
	method := "PUT"
	expires := time.Now().Add(time.Second * 60)

	url, err := storage.SignedURL(bucket, filename, &storage.SignedURLOptions{
		GoogleAccessID: "XXXXXX@developer.gserviceaccount.com",
		PrivateKey:     []byte("-----BEGIN PRIVATE KEY-----\nXXXXXXXX"),
		Method:         method,
		Expires:        expires,
	})
	if err != nil {
		fmt.Println("Error " + err.Error())
	}
	fmt.Println("URL = " + url)
}

Very useful comment:

package main

import (
	"fmt"
	"io/ioutil"
	"log"
	"time"

	"cloud.google.com/go/storage"
	"golang.org/x/oauth2/google"
)

func main() {
	sakeyFile := "/home/tamal/Downloads/xyz.json"

	saKey, err := ioutil.ReadFile(sakeyFile)
	if err != nil {
		log.Fatalln(err)
	}

	cfg, err := google.JWTConfigFromJSON(saKey)
	if err != nil {
		log.Fatalln(err)
	}

	bucket := "go-cloud"
	filename := "mypic3.json"
	method := "GET"
	expires := time.Now().Add(time.Second * 60)

	url, err := storage.SignedURL(bucket, filename, &storage.SignedURLOptions{
		GoogleAccessID: cfg.Email,
		PrivateKey:     cfg.PrivateKey,
		Method:         method,
		Expires:        expires,
	})
	if err != nil {
		fmt.Println("Error " + err.Error())
	}
	fmt.Println(url)
}