Getting the GitLab runner registration token from the command line - docker

Question

Context
To automate adding local GitLab runners to a local GitLab server instance running on docker, I wrote a boilerplate code that downloads and installs a Selenium browser that logs into GitLab and navigates to the GitLab runner section within the admin options, then clicks on "Register an instance runner" and searches for the "unhide" button, and then reads the runner registration token from the source code. This is a somewhat elaborate process, and currently not stable.
The GitLab server runs in docker (sudo docker ps -a):
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
51asd8ed1a44 gitlab/gitlab-ce:latest "/assets/wrapper" 49 minutes ago Up 49 minutes (healthy) 0.0.0.0:80->80/tcp, :::80->80/tcp, 0.0.0.0:443->443/tcp, :::443->443/tcp, 0.0.0.0:23->22/tcp, :::23->22/tcp gitlab
Question
How can one retrieve the GitLab runner registration token from the CLI from GitLab directly?

Answer 1

You can get a specific Project's runner registration token from the Get Single Project API operation. In the response, it will have an attribute called runners_token which matches the runner registration token for the queried project.
curl --location --request GET 'https://gitlab.example.com/api/v4/projects/1' --header 'Authorization: Bearer xxxTOKENxxx'
At the moment, there doesn't appear to be a way to retrieve the Instance-wide registration token you can see from the Admin area, however unless the token is frequently reset, you could store it securely somewhere and use it when you register new runners until it changes.
For example, you can access a project's CI Variables via the API, so you could store the Admin registration token in a protected project, then access that via the Get Single Variable API:
curl --header "PRIVATE-TOKEN: <your_access_token>" "https://gitlab.example.com/api/v4/projects/1/variables/TEST_VARIABLE_1"
This returns the following information about the variable:
{
"key": "TEST_VARIABLE_1",
"variable_type": "env_var",
"value": "TEST_1",
"protected": false,
"masked": true,
"environment_scope": "*"
}