Pub credentials.json

main.go

package main

import (
	"encoding/json"
	"flag"
	"fmt"
	"io/ioutil"
	"log"
	"os"

	"golang.org/x/oauth2/google"
)

const usagePrefix = `Makes a pub credentials.json file given a service account private key

Usage: go run ./main.go [OPTIONS]

OPTIONS:
`

var (
	keyFlag = flag.String("key", "service_account_key.json", "Private key json file")
)

func main() {
	// Flag setup
	flag.Usage = func() {
		fmt.Fprint(os.Stderr, usagePrefix)
		flag.PrintDefaults()
	}
	flag.Parse()

	// Get token info
	jsonKey, err := ioutil.ReadFile(*keyFlag)
	if err != nil {
		log.Fatalf("Could not read %s: %v", *keyFlag, err)
	}
	tokenSource, err := google.JWTAccessTokenSourceFromJSON([]byte(jsonKey), "")
	if err != nil {
		log.Fatalf("Error getting token source: %v", err)
	}
	token, err := tokenSource.Token()
	if err != nil {
		log.Fatalf("Error getting token: %v", err)
	}
	json.NewEncoder(os.Stdout).Encode(map[string]interface{}{
		"accessToken":   token.AccessToken,
		"refreshToken":  token.RefreshToken,
		"tokenEndpoint": google.Endpoint.TokenURL,
		"expiration":    token.Expiry.UnixNano() / 1000000, // Milliseconds
	})
}