Add variable for host absolute path

[atli-c]

Is your feature request related to a problem? Please describe.
I need the absolute path to project directory as it is on the host OS (not as seen within container).

When developing I use containers that are bind-mounted which require absolute path to the source code. Deployment of those containers are run in a CI job with image: …. I.e. deployment is run in a container where CI_PROJECT_DIR points to /gcl-builds which is absolute path within the container, not on my machine (the host OS)

Describe the solution you'd like
A new variable with absolute path. Possible names:

• HOST_CI_PROJECT_DIR
• LOCAL_CI_PROJECT_DIR

Describe alternatives you've considered
Workaround:

job-supplying-full-path:
  # No image. "shell" executor
  script:
    - echo "LOCAL_WORKING_DIR=$PWD" | tee .full-path-on-host-os.env
  artifacts:
    reports:
      dotenv: .full-path-on-host-os.env
job-requiring-full-path:
  image: busybox  # Runs in container - "docker" executor
  needs:
    - job-supplying-full-path
  variables:
    LOCAL_PWD: $PWD  # This does not work. Empty value.
  script:
    - echo "Container '$CI_PROJECT_DIR'"
    - echo "Container '$PWD'"
    - echo "Variable workaround? '$LOCAL_PWD'"
    - echo "Variable via other job '$LOCAL_WORKING_DIR'"

Output from 'job-requiring-full-path':

Container '/gcl-builds'
Container '/gcl-builds'
Variable workaround? ''
Variable via other job '/home/example/src/project'

Additional context
If the value of new variable is problematic (information leak?) then maybe the variable could be opt-in to limit info-leak? Like with the @ annotation.

[firecow]

This would be very useful, when deploying services locally to minikube what needs mounting