Support environment predefined variables in job rules

What does this MR do and why?

This MR supports CI_ENVIRONMENT_NAME, CI_ENVIRONMENT_ACTION, CI_ENVIRONMENT_TIER and CI_ENVIRONMENT_URL variables in job rules. This is also necessary to pass upstream environment context to the downstream pipeline in Support environment keyword with trigger keyword (!128693 - merged).

This change is behind support_ci_environment_variables_in_job_rules feature flag and it's disabled by default.

Related to

• Support `environment` keyword with `trigger` ke... (#369061 - closed)
• Add support for CI_ENVIRONMENT_NAME to be used ... (!106093 - merged)
• Support environment keyword with trigger keyword (!128693 - merged)

Screenshots or screen recordings

Peek_2023-08-22_15-56

How to set up and validate locally

1. Enable support_ci_environment_variables_in_job_rules feature flag.
2. Create a project.
3. Add .gitlab-ci.yml with the following content:

   deploy:
       script: "deploy"
       environment:
           name: review/$CI_COMMIT_REF_NAME
           deployment_tier: development
           url: https://gitlab.com
       rules:
           - if: $CI_ENVIRONMENT_NAME =~ /^review\// && $CI_ENVIRONMENT_ACTION == "start" && $CI_ENVIRONMENT_TIER == "development" && $CI_ENVIRONMENT_URL == "https://gitlab.com"

4. Make sure a pipeline with the deploy job is created.

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.