Overriding variable in called feature - karate

Question

I'm using Karate to write integration tests for a REST API. In all test scenarios I have to login users to get an authentification token for all calls related to the REST API. So I want to put the login logic into a separate Karate feature, so I don't have to copy and paste the login API call to all other Scenarios.
From the doku I was able to figure out how to call my login.feature in another feature (logout, with needs a logged in user). I'm also able to pass the username and password to the called login.feature from my calling logout.feature. But I also want my login.feature to be executable on it's own, so I have to define username and password in the login.feature. But if I do so, I'm not able to override this variables from the calling feature.
If I run the logout.feature like follows, the login.feature is not using the email parameter I'm providing in the logout.feature If I delete the email variable from login.feature, it is using the parameter from logout.feature, but then I can't run the login.feature on its own.
Calling logout.feature:
Feature: Login/Logout Test
Background:
* url urlBase http://localhost:5000
* def login = call read('classpath:ires/session/login.feature') {email: "user1#test.com", password: "test"}
* def authToken = login.authToken
Scenario: Testing logout via PUT
Given path '/sessions/logout'
Given param TOKEN = authToken
And request {}
When method PUT
Then status 202
Called login.feature:
Feature: Logs in the given user
Background:
* url urlBase http://localhost:5000
* def email = "user2#test.com"
* def password = "test"
Scenario: Test login via POST
Given path '/sessions/login'
And request {email: '#(email)', password: '#(password)'}
And print email
When method post
Then status 200
And def authToken = response

Answer 1

My suggestion is you can create a login-caller.feature that will call the login.feature with the proper argument passed. Another option is to have email and password defined globally in karate-config.js.
I don't recommend depending on undefined variables as it leads to maintainability problems in the long run, but you can do this kind of conditional check:
* def email = typeof email == 'undefined' ? 'user2#test.com' : email