This is a sample golang script for retrieving access token using Service Account of Google by Google's OAuth2 package.
The script without using Google's OAuth2 package is here.
package main
import (
"encoding/json"
"fmt"
"io/ioutil"
"os"
"golang.org/x/oauth2"
"golang.org/x/oauth2/google"
"golang.org/x/oauth2/jwt"
)
func serviceAccount(credentialFile string) (*oauth2.Token, error) {
b, err := ioutil.ReadFile(credentialFile)
if err != nil {
return nil, err
}
var c = struct {
Email string `json:"client_email"`
PrivateKey string `json:"private_key"`
}{}
json.Unmarshal(b, &c)
config := &jwt.Config{
Email: c.Email,
PrivateKey: []byte(c.PrivateKey),
Scopes: []string{
"https://www.googleapis.com/auth/drive.metadata.readonly",
},
TokenURL: google.JWTTokenURL,
}
token, err := config.TokenSource(oauth2.NoContext).Token()
if err != nil {
return nil, err
}
return token, nil
}
func main() {
token, err := serviceAccount("credentials.json") // Please set here
if err != nil {
fmt.Println(err)
os.Exit(1)
}
fmt.Println(res)
}