[PATCH v1 1/1] gitlab-ci: Let project define runner using environment variables

[Leonardo Bras <leobras@redhat.com>]

Currently it's not possible to select which runner will handle a pipeline
without changing the codebase.

Add CI_TAGS environment variable, which can be used to select a runner
either from a commit message, or directly from Gitlab interface.

Also add Documentation for this variable.

Signed-off-by: Leonardo Bras <leobras@redhat.com>
---

This patch goes on top on a previous patchset sent by Helen:
https://lore.kernel.org/all/20240228225527.1052240-1-helen.koike@collabora.com/

With this patch I could run CI with gitlab.com runners, by setting
CI_TAGS=saas-linux-medium-amd64 

The result of this pipeline can be seen in:
https://gitlab.com/linux-kernel/linux/-/pipelines/1228999646

 Documentation/ci/gitlab-ci/gitlab-ci.rst | 5 +++++
 ci/gitlab-ci/yml/gitlab-ci.yml           | 2 ++
 2 files changed, 7 insertions(+)

diff --git a/Documentation/ci/gitlab-ci/gitlab-ci.rst b/Documentation/ci/gitlab-ci/gitlab-ci.rst
index 4f7ef03cca95..18360da835bd 100644
--- a/Documentation/ci/gitlab-ci/gitlab-ci.rst
+++ b/Documentation/ci/gitlab-ci/gitlab-ci.rst
@@ -304,20 +304,25 @@ Description of Each Variable
 **KCI_CHECKPATCH_OPTIONS**
     Used in `checkpatch.pl "$KCI_CHECKPATCH_OPTIONS"` (see checkpatch
     documentation). It is commonly used with the --ignore flag to suppress
     specific warnings generated by checkpatch.pl. It can also be defined in the
     commit message, since it is evaluated in run time.
 
 **KCI_PATCH_SERIES_SIZE**
     Used to define the size of the patch series, see `job: checkpatch` section
     above. It is evaluated in run time, and can be set in the commit message.
 
+**CI_TAGS**
+    Used to help choose which runner will deal with the current pipeline.
+    If using Gitlab.com runners, set saas-linux-medium-amd64 or a better runner
+    so there is enough resources to build & commit the base image.
+
 .. _triggering-pipelines-from-command-line:
 
 Triggering Pipelines from Command Line
 --------------------------------------
 
 Pipelines can be triggered from the command line with custom variables using the
 `GitLab CLI tool <https://docs.gitlab.com/ee/editor_extensions/gitlab_cli>`_.
 
 Example:
 
diff --git a/ci/gitlab-ci/yml/gitlab-ci.yml b/ci/gitlab-ci/yml/gitlab-ci.yml
index 57b9c0290471..359b7715e3ab 100644
--- a/ci/gitlab-ci/yml/gitlab-ci.yml
+++ b/ci/gitlab-ci/yml/gitlab-ci.yml
@@ -33,20 +33,22 @@ workflow:
     - if: $FORCE_CI == 'true'
 
 variables:
   FDO_UPSTREAM_REPO: helen.fornazier/linux   # The repo where to look for cached images
     # ccache builds in gitlab-runner to speed up builds
   SMATCH_DB_DIR: /smatch/smatch_data
   # exit code of bash script on `script` will be the exit code of the job
   FF_USE_NEW_BASH_EVAL_STRATEGY: "true"
 
 default:
+  tags:
+    - $CI_TAGS
   artifacts:
     paths:
       - artifacts/
     when: always
 
 include:
   - remote: 'https://gitlab.freedesktop.org/freedesktop/ci-templates/-/raw/16bc29078de5e0a067ff84a1a199a3760d3b3811/templates/ci-fairy.yml'
   - remote: 'https://gitlab.freedesktop.org/freedesktop/ci-templates/-/raw/16bc29078de5e0a067ff84a1a199a3760d3b3811/templates/debian.yml'
 
   - ci/gitlab-ci/yml/kernel-combinations.yml
-- 
2.44.0