Only allow validated commits on master

Question

Context

We have a repo, hosted on a local gitlab instance.

It contains a ressource file, which should be valid. The validity is checked by a given script.

What I want

I want to ensure that, whenever the master branch is updated on the gitlab repo, the file at the new head of master passes the validation script.

Possibilities explored

• all updates to master should go through a Merge Request

  1. I haven't found a way to enable / disable the Merge button based on the result of a script,
  2. I could upload a script in the bare hooks/ directory of the bare git repo managed by gitlab, but I don't know of a pre-merge hook in git

• updates to master can be pushed by developpers

  3. I know how to write and upload an update hook, which validates the master branch on the bare git repo,
     I don't know how to prevent other ways to update the master branch

Question

Using gitlab and git, how can I make sure that updates to the master branch only allow hops to validated versions of the file ?

Answer 1

Using Gitlab pipelines

What you're trying to setup is Continous Integration, (in Gitlab known as "Pipeline") to check whether a merge request will pass or fail your script. Check out the Gitlab features page

The setup is quite straightforward:

1. You create a .gitlab-ci.yml file, which describes what script needs to be run in order to test your resource file. Please note that the script should exit with 0 if the test passes and with a non-zero value otherwise.
2. Dependent on whether your project is open source you choose if you want to use Gitlab's shared runners. A "runner" is a server application which runs your script every time it is toggled. You can setup a runner on your own server or use Gitlab's Runners.
3. Once setup correctly GitLab will always show if your resource file is valid or not.

Source: https://docs.gitlab.com/ee/ci/pipelines.html

Example

This short example might help you to setup your .gitlab-ci.yml file

stages:
    - tests

ResourceFileTests:
    stage: tests
    allow_failure: false
    script:
        - bash /path/to/the/validation_script.sh

You can use GitLab's CI lint tool to check whether your configuration file is valid or not.