Automate Heroku CLI login

You can generate a non-expiring OAuth token then pass it to the CLI via an environment variable. This is useful if you need to run Heroku CLI commands indefinitely from a scheduler and you don't want the login to expire. Do it like this (these are not actual Tokens and IDs, BTW):

$ heroku authorizations:create
Creating OAuth Authorization... done
Client:      <none>
ID:          80fad839-876b-4ea0-a41e-6a9a2fb0cf97
Description: Long-lived user authorization
Scope:       global
Token:       ddf4a0e5-9294-4c5f-8820-b51c52fce4f9
Updated at:  Fri Aug 02 2019 21:26:09 GMT+0100 (British Summer Time) (less than a minute ago)

Get the token (not the ID) from that authorization and pass that it to your CLI:

$ HEROKU_API_KEY='ddf4a0e5-9294-4c5f-8820-b51c52fce4f9' heroku run ls --app my-app
Running ls on ⬢ my-app... up, run.2962 (Hobby)
<some file names>
$

By the way, this is a also a solution to the problem of how to use the Heroku CLI when you have MFA enabled on the Heroku account but your machine doesn't have a web browser e.g., if you are working on an EC2 box via SSH:

$ heroku run ls --app my-app
heroku: Press any key to open up the browser to login or q to exit:
 ›   Error: quit
$ HEROKU_API_KEY='ddf4a0e5-9294-4c5f-8820-b51c52fce4f9' heroku run ls --app my-app
Running ls on ⬢ my-app... up, run.5029 (Hobby)
<some file names>
$

EDIT: For Windows Machines

After you run heroku authorizations:create, copy the "Token", and run the following commands:

set HEROKU_API_KEY=ddf4a0e5-9294-4c5f-8820-b51c52fce4f9
heroku run ls --app my-app

The Heroku CLI only uses your username and password to retrieve your API key, which it stores in your ~/.netrc file ($HOME\_netrc on Windows).

You can manually retrieve your API key and add it to your ~/.netrc file:

1. Log into the Heroku web interface
2. Navigate to your Account settings page
3. Scroll down to the API Key section and click the Reveal button
4. Copy your API key
5. Open your ~/.netrc file, or create it, with your favourite text editor

6. Add the following content:

   machine api.heroku.com
     login <your-email@address>
     password <your-api-key>
   machine git.heroku.com
     login <your-email@address>
     password <your-api-key>
   

   Replace <your-email@address> with the email address registered with Heroku, and <your-api-key> with the API key you copied from Heroku.

This should manually accomplish what heroku login does automatically. However, I don't recommend this. Running heroku login does the same thing more easily and with fewer opportunities to make a mistake.

If you decide to copy ~/.netrc files between machines or accounts you should be aware of two major caveats:

• This file is used by many other programs; be careful to only copy the configuration stanzas you want.
• Your API key offers full programmatic access to your account. You should protect it as strongly as you protect your password.

Please be very careful if you intend to log into Heroku using any mechanism other than heroku login.