How do I associate a git branch to a kubernetes namespace?

Say I want to map git branches to k8s namespaces, like this:

for my Gitlab CI pipeline to deploy helm charts to the right namespaces, based on the branch. Where do I put this mapping? I tried with a bash If in the CI script and with Gitlab CI variables. Both worked but both were kludges. I was told to use something like values_prd.yaml and values_dev.yaml (I belive they meant values_master.yaml and values_devel.yaml) but that makes no sense to me right now, as I don't belive you can't tell helm what namespace to install charts to by passing values (can you?).

TLDR: How/Where do I map branches to namespaces?

Edit: Here's my .gitlab-ci.yml.

Answer

We're missing some context here. Assuming you're running helm from your gitab-ci.yml: you may be able to have helm loading its values file based on your environment: eg values\_${CI\_COMMIT\_REF\_NAME}.yml (and then, yes, _master or _devel, instead of _prd and _dev ... unless you rename your branches otherwise). Beyond GitLab CI specifics, for such a task, note that ArgoCD could be a good candidate - and won't lock you with some git vendor. Added my .gitlab-ci.yml. It's for a "toy" project for learning.