.gitlab-ci GIT submodule check

.gitlab-ci.yml

variables:
  GIT_SUBMODULE_STRATEGY: recursive

check_submodule_updates:
  stage: test
  # a warning is sufficient for this check, it should not prevent a deployment
  allow_failure: true
  script:
    - cd path-to-submodule
    - git fetch origin
    - |
      if [ "$(git log origin/master ^HEAD)" != "" ]; then
        echo -e "\nNew git commits for submodule\n\nPlease update with\n\ncd path-to-submodule\ngit pull origin master\ncd ../../\ngit commit -am '[TASK] update submodule'\n\nMissing commits:\n"
        git log origin/master ^HEAD
        exit 1
      fi