Environment variables on `process.env` sometimes not available in hooks.js in local dev

[josefaidt]

Describe the bug

I'm looking to use the handle hook to add authentication and authorization middleware to my API routes, however the variables needed to verify user JWT's are sometimes not available when the hook runs, but only in local development. In my experience these variables were available just once after upgrading dependencies to use Vite 2.7.1, however on subsequent attempts/restarts of the dev server these variables were no longer available and thus all API attempts would be unauthorized. I've attempted to remove the .svelte-kit directory, node_modules, lockfile, and reinstall to no avail.

It is important to note this is only experienced during local development with svelte-kit dev, and may actually be a Vite-related issue (given the Svelte-Kit scope I decided to file here first to see what y'all's thoughts are).

This can be mitigated by adding a small Vite plugin to load secrets with dotenv

// svelte.config.js
// ...
/** @type {import('@sveltejs/kit').Config} */
const config = {
  kit: {
    adapter: adapter(),

    // hydrate the <div id="svelte"> element in src/app.html
    target: '#svelte',

+   vite: {
+     plugins: [
+       (function LoadSecrets() {
+         return {
+           name: 'load-secrets',
+           configureServer: async () => {
+             ;(await import('dotenv')).config()
+           }
+         }
+       })()
+     ]
+   }
  }
}

And for reference, the hooks.js file:

export async function handle({ request, resolve }) {
  let user = await authenticate(request) // verifies JWT, requires 3 server-side env vars

  request.locals.user = user
  request.locals.isAuthenticated = !!user

  if (request.path.startsWith('/api')) {
    if (!user) {
      return {
        status: 401,
        body: JSON.stringify({
          error: {
            message: 'Unauthorized'
          }
        })
      }
    }

    if (request.path.startsWith('/api/admin') && !isAdmin(user)) {
      return {
        status: 403,
        body: JSON.stringify({
          error: {
            message: 'Invalid Admin'
          }
        })
      }
    }
  }

  const response = await resolve(request)
  return response
}

Reproduction

1. Create a Svelte-Kit app with npm init svelte@next my-app
2. Create a .env file in the project root, add an environment variable

   MY_VAR="hello, world!"
   

3. Create src/hooks.js:

   export async function handle({ request, resolve }) {
     console.log(process.env['MY_VAR']) // sometimes undefined
     const response = await resolve(request)
     return response
   }

4. Run the dev server with svelte-kit dev and observe error

Logs

No response

System Info

System:
    OS: macOS 11.5.1
    CPU: (4) x64 Intel(R) Core(TM) i7-7567U CPU @ 3.50GHz
    Memory: 30.61 MB / 16.00 GB
    Shell: 3.3.1 - /usr/local/bin/fish
  Binaries:
    Node: 16.13.0 - /var/folders/pp/ty2pnrf50xg0zgv3033j83_m0000gn/T/fnm_multishells/917_1639061469329/bin/node
    Yarn: 1.23.0-20210726.1745 - /var/folders/pp/ty2pnrf50xg0zgv3033j83_m0000gn/T/fnm_multishells/917_1639061469329/bin/yarn
    npm: 8.1.0 - /var/folders/pp/ty2pnrf50xg0zgv3033j83_m0000gn/T/fnm_multishells/917_1639061469329/bin/npm
  Browsers:
    Brave Browser: 92.1.28.105
    Chrome: 96.0.4664.93
    Chrome Canary: 98.0.4758.2
    Edge: 96.0.1054.43
    Firefox: 94.0.1
    Firefox Developer Edition: 68.0
    Safari: 14.1.2
  npmPackages:
    @sveltejs/adapter-auto: next => 1.0.0-next.3 
    @sveltejs/adapter-vercel: next => 1.0.0-next.31 
    @sveltejs/kit: next => 1.0.0-next.201 
    svelte: ^3.44.0 => 3.44.2 

dependencies are installed with pnpm, Vite version is 2.7.1

Severity

serious, but I can work around it

Additional Information

No response

[korywka]

Thanks for workaround. Confirm this bug with 1.0.0-next.202 too.

[jitheshkt]

I am also facing the same issue. Your walkaround works perfectly, but only on Development. On production, MY_VAR is always undefined. Any way to bypass?

[Feuerhamster]

Same issue here

[bluwy]

SvelteKit/Vite had never load .env variables for the server-side, so I'm not sure how it used to work before. dotenv would be needed if you want to use .env variables, though I'm not familiar where to place this, perhaps the workaround vite plugin is the right way (?). With that said, SvelteKit hasn't officially supported it since process.env isn't available in all environments, and we don't have a solution for it yet.

Note: We have a brief documentation about it.

[josefaidt]

Hey @bluwy thanks for the confirmation. I haven't run into issues using process.env elsewhere in the app (like api routes), but it seems this issue only affects the hooks.js file. Vite's dev server should read from .env, where this is sufficient for local development as I am not uploading the .env file to production.

It's worth noting this is only affecting my dev environment, and production (on Vercel, using the Vercel adapter) is okay. I guess the confusion that motivated me filing this issue is due to how we're able to use process.env in API routes but not in hooks, sometimes.

[korywka]

this solution works for DEV env. I hope it works for production env too:

vite: {
      define: (() => {
        const result = {};
        const env = dotenv.config().parsed;
        Object.entries(env).forEach(([k, v]) => result[`process.env.${k}`] = `'${v}'`);
        return result;
      })(),
},

[10p-freddo]

You don't need a plugin, either of these will work:

NODE_OPTIONS='-r dotenv/config' npm run dev

npx --node-options='-r dotenv/config' svelte-kit dev

[Rich-Harris]

Going to close this in favour of #4296, which covers this along with various other aspects of env vars