Fetch secret from Vault when initializing next.js - next.js

Question

I'm using next.js with the library https://github.com/auth0/nextjs-auth0/
To initialise that library I need to fetch a secret from Vault using async/await but I get a Promise { <pending> }
I would have thought the following would work:
// utils/auth0.js
import { initAuth0 } from '#auth0/nextjs-auth0';
const vault = require('./vault');
async function getSecretFromVault() {
const res = await vault.fetchSecret();
console.log(res); // shows my secret correctly
return res;
}
const secret = getSecretFromVault();
console.log(secret); // shows Promise { <pending> }
export default initAuth0({
clientId: "my_ID",
clientSecret: secret // this will be invalid: UI shows "client_id is required"
....
});
What is the right way to do this?

Answer 1

An async method returns a promise, you should use await in order to get the async data.
Since module export is a sync it is better to export an async method which will make your call to Vault and return the initialization of Auth0.
// utils/auth0.js
import { initAuth0 } from '#auth0/nextjs-auth0';
const vault = require('./vault');
async function getSecretFromVault() {
const res = await vault.fetchSecret();
console.log(res); // shows my secret correctly
return res;
}
let instance;
async function getAuth0() {
if(instance) {
return Promise.resolve(instance);
}
const secret = await getSecretFromVault();
// -------------^
instance = initAuth0({
clientId: 'my_ID',
clientSecret: secret, // this will be invalid: UI shows "client_id is required"
});
return instance;
}
export default getAuth0;
// usage
import getAuth0 from './utils/auth0';
export default async function login(req, res) {
const auth0 = await getAuth0();
// --------------------^ get instance
try {
await auth0.handleLogin(req, res);
} catch (error) {
console.error(error);
res.status(error.status || 400).end(error.message);
}
}