Add Cilium support into kube_client

Cilium apis will be used in the
following MRs which will be adding
CiliumNetworkPolicy.

changelogs/unreleased/add_cilium_into_kube_client.yml

+---
+title: Add Cilium APIs as part of kube_client
+merge_request: 37526
+author:
+type: changed

lib/gitlab/kubernetes/kube_client.rb

@@ -21,7 +21,8 @@ module Gitlab
         istio: { group: 'apis/networking.istio.io', version: 'v1alpha3' },
         knative: { group: 'apis/serving.knative.dev', version: 'v1alpha1' },
         metrics: { group: 'apis/metrics.k8s.io', version: 'v1beta1' },
-        networking: { group: 'apis/networking.k8s.io', version: 'v1' }
+        networking: { group: 'apis/networking.k8s.io', version: 'v1' },
+        cilium_networking: { group: 'apis/cilium.io', version: 'v2' }
       }.freeze
 
       SUPPORTED_API_GROUPS.each do |name, params|
@@ -95,6 +96,14 @@ module Gitlab
         :delete_network_policy,
         to: :networking_client
 
+      # CiliumNetworkPolicy methods delegate to the apis/cilium.io api
+      # group client
+      delegate :create_cilium_network_policy,
+        :get_cilium_network_policies,
+        :update_cilium_network_policy,
+        :delete_cilium_network_policy,
+        to: :cilium_networking_client
+
       attr_reader :api_prefix, :kubeclient_options
 
       DEFAULT_KUBECLIENT_OPTIONS = {

spec/lib/gitlab/kubernetes/kube_client_spec.rb

@@ -227,6 +227,20 @@ RSpec.describe Gitlab::Kubernetes::KubeClient do
     end
   end
 
+  describe '#cilium_networking_client' do
+    subject { client.cilium_networking_client }
+
+    it_behaves_like 'a Kubeclient'
+
+    it 'has the cilium API group endpoint' do
+      expect(subject.api_endpoint.to_s).to match(%r{\/apis\/cilium.io\Z})
+    end
+
+    it 'has the api_version' do
+      expect(subject.instance_variable_get(:@api_version)).to eq('v2')
+    end
+  end
+
   describe '#metrics_client' do
     subject { client.metrics_client }
 
@@ -380,6 +394,30 @@ RSpec.describe Gitlab::Kubernetes::KubeClient do
     end
   end
 
+  describe 'cilium API group' do
+    let(:cilium_networking_client) { client.cilium_networking_client }
+
+    [
+      :create_cilium_network_policy,
+      :get_cilium_network_policies,
+      :update_cilium_network_policy,
+      :delete_cilium_network_policy
+    ].each do |method|
+      describe "##{method}" do
+        include_examples 'redirection not allowed', method
+        include_examples 'dns rebinding not allowed', method
+
+        it 'delegates to the cilium client' do
+          expect(client).to delegate_method(method).to(:cilium_networking_client)
+        end
+
+        it 'responds to the method' do
+          expect(client).to respond_to method
+        end
+      end
+    end
+  end
+
   describe 'non-entity methods' do
     it 'does not proxy for non-entity methods' do
       expect(client).not_to respond_to :proxy_url