Using Gitlab username&password for another service

Hi all.

In my work, we need to trigger a service that requires user&password.

While the easy solution will be creating a special account for the CI, we prefer that each user will use its own credentials

Technically, the credentials we use for gitlab are identical to this service, so the first question is it possible to somehow use those credentials? some environment variable or something?

Another options, is to define variables by ourself, but I didn’t find an option to do such thing per user, is it possible? If so, what about developers that can’t enter the settings?