Make KUBECONFIG nil if KUBE_TOKEN is nil

Having an invalid KUBECONFIG without a token in it is not helpful. This
only became possible recently now that we are creating a separate
namespace and service account (and hence token) to send to the runners.
This led to somewhat surprising results when troubleshooting
https://gitlab.com/gitlab-org/gitlab-ce/issues/53879 as I found that the
KUBECONFIG was still being passed but KUBE_TOKEN was not. These things
really should have been linked.

Furthermore now that we are also using the [presence of KUBECONFIG to
decide whether or not to run build steps in Auto
DevOps](https://gitlab.com/gitlab-org/gitlab-ce/blob/294d15be3e9497e7b67e1f9131ce9d5c0d68406c/lib/gitlab/ci/templates/Auto-DevOps.gitlab-ci.yml#L164)
I think it makes even more sense to ensure that KUBECONFIG is a complete
config if passed to a job.

1 files changed, 1 insertions, 3 deletions

diff --git a/app/models/clusters/platforms/kubernetes.rb b/app/models/clusters/platforms/kubernetes.rb
index 3c5d7756eec..49f973380d7 100644
--- a/app/models/clusters/platforms/kubernetes.rb
+++ b/app/models/clusters/platforms/kubernetes.rb
@@ -90,13 +90,11 @@ module Clusters
             # Clusters::KubernetesNamespace, so once migration has been completed,
             # this 'else' branch will be removed. For more information, please see
             # https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/22433
-            config = YAML.dump(kubeconfig)
-
             variables
               .append(key: 'KUBE_URL', value: api_url)
               .append(key: 'KUBE_TOKEN', value: token, public: false)
               .append(key: 'KUBE_NAMESPACE', value: actual_namespace)
-              .append(key: 'KUBECONFIG', value: config, public: false, file: true)
+              .append(key: 'KUBECONFIG', value: kubeconfig, public: false, file: true)
           end
         end
       end