Include CRUD endpoints for Cluster API40473-api-support-for-kubernetes-integration

Adds the following initial CRUD endpoints for Clusters API:

- GET list of clusters
- GET specific cluster
- POST add existing cluster (mimic of "Add cluster")
- PUT update cluser
- DELETE destroy cluster

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/40473

5 files changed, 631 insertions, 0 deletions

diff --git a/changelogs/unreleased/40473-api-support-for-kubernetes-integration.yml b/changelogs/unreleased/40473-api-support-for-kubernetes-integration.yml
new file mode 100644
index 00000000000..5567aad6320
--- /dev/null
+++ b/changelogs/unreleased/40473-api-support-for-kubernetes-integration.yml
@@ -0,0 +1,5 @@
+---
+title: Add API Support for Kubernetes integration
+merge_request: 23922
+author:
+type: added
diff --git a/lib/api/api.rb b/lib/api/api.rb
index 19da0b2c434..72f979220d7 100644
--- a/lib/api/api.rb
+++ b/lib/api/api.rb
@@ -129,6 +129,7 @@ module API
     mount ::API::PagesDomains
     mount ::API::Pipelines
     mount ::API::PipelineSchedules
+    mount ::API::ProjectClusters
     mount ::API::ProjectExport
     mount ::API::ProjectImport
     mount ::API::ProjectHooks
diff --git a/lib/api/entities.rb b/lib/api/entities.rb
index 7116ab2882b..7b83188c878 100644
--- a/lib/api/entities.rb
+++ b/lib/api/entities.rb
@@ -1516,5 +1516,38 @@ module API
       expose :from_content
       expose :to_content
     end
+
+    module Platform
+      class Kubernetes < Grape::Entity
+        expose :api_url
+        expose :namespace
+        expose :authorization_type
+        expose :ca_cert
+      end
+    end
+
+    module Provider
+      class Gcp < Grape::Entity
+        expose :cluster_id
+        expose :status_name
+        expose :gcp_project_id
+        expose :zone
+        expose :machine_type
+        expose :num_nodes
+        expose :endpoint
+      end
+    end
+
+    class Cluster < Grape::Entity
+      expose :id, :name, :created_at
+      expose :provider_type, :platform_type, :environment_scope, :cluster_type
+      expose :user, using: Entities::UserBasic
+      expose :platform_kubernetes, using: Entities::Platform::Kubernetes
+      expose :provider_gcp, using: Entities::Provider::Gcp
+    end
+
+    class ClusterProject < Cluster
+      expose :project, using: Entities::BasicProjectDetails
+    end
   end
 end
diff --git a/lib/api/project_clusters.rb b/lib/api/project_clusters.rb
new file mode 100644
index 00000000000..7aada260297
--- /dev/null
+++ b/lib/api/project_clusters.rb
@@ -0,0 +1,142 @@
+# frozen_string_literal: true
+
+module API
+  class ProjectClusters < Grape::API
+    include PaginationParams
+
+    before { authenticate! }
+
+    # EE::API::ProjectClusters will
+    # override these methods
+    helpers do
+      params :create_params_ee do
+      end
+
+      params :update_params_ee do
+      end
+    end
+
+    params do
+      requires :id, type: String, desc: 'The ID of the project'
+    end
+    resource :projects, requirements: API::NAMESPACE_OR_PROJECT_REQUIREMENTS do
+      desc 'Get all clusters from the project' do
+        detail 'This feature was introduced in GitLab 11.7.'
+        success Entities::Cluster
+      end
+      params do
+        use :pagination
+      end
+      get ':id/clusters' do
+        authorize! :read_cluster, user_project
+
+        present paginate(clusters_for_current_user), with: Entities::Cluster
+      end
+
+      desc 'Get specific cluster for the project' do
+        detail 'This feature was introduced in GitLab 11.7.'
+        success Entities::ClusterProject
+      end
+      params do
+        requires :cluster_id, type: Integer, desc: 'The cluster ID'
+      end
+      get ':id/clusters/:cluster_id' do
+        authorize! :read_cluster, cluster
+
+        present cluster, with: Entities::ClusterProject
+      end
+
+      desc 'Adds an existing cluster' do
+        detail 'This feature was introduced in GitLab 11.7.'
+        success Entities::ClusterProject
+      end
+      params do
+        requires :name, type: String, desc: 'Cluster name'
+        optional :enabled, type: Boolean, default: true, desc: 'Determines if cluster is active or not, defaults to true'
+        requires :platform_kubernetes_attributes, type: Hash, desc: %q(Platform Kubernetes data) do
+          requires :api_url, type: String, allow_blank: false, desc: 'URL to access the Kubernetes API'
+          requires :token, type: String, desc: 'Token to authenticate against Kubernetes'
+          optional :ca_cert, type: String, desc: 'TLS certificate (needed if API is using a self-signed TLS certificate)'
+          optional :namespace, type: String, desc: 'Unique namespace related to Project'
+          optional :authorization_type, type: String, values: Clusters::Platforms::Kubernetes.authorization_types.keys, default: 'rbac', desc: 'Cluster authorization type, defaults to RBAC'
+        end
+        use :create_params_ee
+      end
+      post ':id/clusters/user' do
+        authorize! :create_cluster, user_project
+
+        user_cluster = ::Clusters::CreateService
+          .new(current_user, create_cluster_user_params)
+          .execute
+
+        if user_cluster.persisted?
+          present user_cluster, with: Entities::ClusterProject
+        else
+          render_validation_error!(user_cluster)
+        end
+      end
+
+      desc 'Update an existing cluster' do
+        detail 'This feature was introduced in GitLab 11.7.'
+        success Entities::ClusterProject
+      end
+      params do
+        requires :cluster_id, type: Integer, desc: 'The cluster ID'
+        optional :name, type: String, desc: 'Cluster name'
+        optional :platform_kubernetes_attributes, type: Hash, desc: %q(Platform Kubernetes data) do
+          optional :api_url, type: String, desc: 'URL to access the Kubernetes API'
+          optional :token, type: String, desc: 'Token to authenticate against Kubernetes'
+          optional :ca_cert, type: String, desc: 'TLS certificate (needed if API is using a self-signed TLS certificate)'
+          optional :namespace, type: String, desc: 'Unique namespace related to Project'
+        end
+        use :update_params_ee
+      end
+      put ':id/clusters/:cluster_id' do
+        authorize! :update_cluster, cluster
+
+        update_service = Clusters::UpdateService.new(current_user, update_cluster_params)
+
+        if update_service.execute(cluster)
+          present cluster, with: Entities::ClusterProject
+        else
+          render_validation_error!(cluster)
+        end
+      end
+
+      desc 'Remove a cluster' do
+        detail 'This feature was introduced in GitLab 11.7.'
+        success Entities::ClusterProject
+      end
+      params do
+        requires :cluster_id, type: Integer, desc: 'The Cluster ID'
+      end
+      delete ':id/clusters/:cluster_id' do
+        authorize! :admin_cluster, cluster
+
+        destroy_conditionally!(cluster)
+      end
+    end
+
+    helpers do
+      def clusters_for_current_user
+        @clusters_for_current_user ||= ClustersFinder.new(user_project, current_user, :all).execute
+      end
+
+      def cluster
+        @cluster ||= clusters_for_current_user.find(params[:cluster_id])
+      end
+
+      def create_cluster_user_params
+        declared_params.merge({
+          provider_type: :user,
+          platform_type: :kubernetes,
+          clusterable: user_project
+        })
+      end
+
+      def update_cluster_params
+        declared_params(include_missing: false).without(:cluster_id)
+      end
+    end
+  end
+end
diff --git a/spec/requests/api/project_clusters_spec.rb b/spec/requests/api/project_clusters_spec.rb
new file mode 100644
index 00000000000..e34164aa66a
--- /dev/null
+++ b/spec/requests/api/project_clusters_spec.rb
@@ -0,0 +1,450 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe API::ProjectClusters do
+  include KubernetesHelpers
+
+  let(:current_user) { create(:user) }
+  let(:non_member) { create(:user) }
+  let(:project) { create(:project, :repository) }
+
+  before do
+    project.add_maintainer(current_user)
+  end
+
+  describe 'GET /projects/:id/clusters' do
+    let!(:extra_cluster) { create(:cluster, :provided_by_gcp, :project) }
+
+    let!(:clusters) do
+      create_list(:cluster, 5, :provided_by_gcp, :project, :production_environment,
+                  projects: [project])
+    end
+
+    context 'non-authorized user' do
+      it 'should respond with 404' do
+        get api("/projects/#{project.id}/clusters", non_member)
+
+        expect(response).to have_gitlab_http_status(404)
+      end
+    end
+
+    context 'authorized user' do
+      before do
+        get api("/projects/#{project.id}/clusters", current_user)
+      end
+
+      it 'should respond with 200' do
+        expect(response).to have_gitlab_http_status(200)
+      end
+
+      it 'should include pagination headers' do
+        expect(response).to include_pagination_headers
+      end
+
+      it 'should only include authorized clusters' do
+        cluster_ids = json_response.map { |cluster| cluster['id'] }
+
+        expect(cluster_ids).to match_array(clusters.pluck(:id))
+        expect(cluster_ids).not_to include(extra_cluster.id)
+      end
+    end
+  end
+
+  describe 'GET /projects/:id/clusters/:cluster_id' do
+    let(:cluster_id) { cluster.id }
+
+    let(:platform_kubernetes) do
+      create(:cluster_platform_kubernetes, :configured,
+             namespace: 'project-namespace')
+    end
+
+    let(:cluster) do
+      create(:cluster, :project, :provided_by_gcp,
+             platform_kubernetes: platform_kubernetes,
+             user: current_user,
+             projects: [project])
+    end
+
+    context 'non-authorized user' do
+      it 'should respond with 404' do
+        get api("/projects/#{project.id}/clusters/#{cluster_id}", non_member)
+
+        expect(response).to have_gitlab_http_status(404)
+      end
+    end
+
+    context 'authorized user' do
+      before do
+        get api("/projects/#{project.id}/clusters/#{cluster_id}", current_user)
+      end
+
+      it 'returns specific cluster' do
+        expect(json_response['id']).to eq(cluster.id)
+      end
+
+      it 'returns cluster information' do
+        expect(json_response['provider_type']).to eq('gcp')
+        expect(json_response['platform_type']).to eq('kubernetes')
+        expect(json_response['environment_scope']).to eq('*')
+        expect(json_response['cluster_type']).to eq('project_type')
+      end
+
+      it 'returns project information' do
+        cluster_project = json_response['project']
+
+        expect(cluster_project['id']).to eq(project.id)
+        expect(cluster_project['name']).to eq(project.name)
+        expect(cluster_project['path']).to eq(project.path)
+      end
+
+      it 'returns kubernetes platform information' do
+        platform = json_response['platform_kubernetes']
+
+        expect(platform['api_url']).to eq('https://kubernetes.example.com')
+        expect(platform['namespace']).to eq('project-namespace')
+        expect(platform['ca_cert']).to be_present
+      end
+
+      it 'returns user information' do
+        user = json_response['user']
+
+        expect(user['id']).to eq(current_user.id)
+        expect(user['username']).to eq(current_user.username)
+      end
+
+      it 'returns GCP provider information' do
+        gcp_provider = json_response['provider_gcp']
+
+        expect(gcp_provider['cluster_id']).to eq(cluster.id)
+        expect(gcp_provider['status_name']).to eq('created')
+        expect(gcp_provider['gcp_project_id']).to eq('test-gcp-project')
+        expect(gcp_provider['zone']).to eq('us-central1-a')
+        expect(gcp_provider['machine_type']).to eq('n1-standard-2')
+        expect(gcp_provider['num_nodes']).to eq(3)
+        expect(gcp_provider['endpoint']).to eq('111.111.111.111')
+      end
+
+      context 'when cluster has no provider' do
+        let(:cluster) do
+          create(:cluster, :project, :provided_by_user,
+                 projects: [project])
+        end
+
+        it 'should not include GCP provider info' do
+          expect(json_response['provider_gcp']).not_to be_present
+        end
+      end
+
+      context 'with non-existing cluster' do
+        let(:cluster_id) { 123 }
+
+        it 'returns 404' do
+          expect(response).to have_gitlab_http_status(404)
+        end
+      end
+    end
+  end
+
+  shared_context 'kubernetes calls stubbed' do
+    before do
+      stub_kubeclient_discover(api_url)
+      stub_kubeclient_get_namespace(api_url, namespace: namespace)
+      stub_kubeclient_get_service_account(api_url, "#{namespace}-service-account", namespace: namespace)
+      stub_kubeclient_put_service_account(api_url, "#{namespace}-service-account", namespace: namespace)
+
+      stub_kubeclient_get_secret(
+        api_url,
+        {
+          metadata_name: "#{namespace}-token",
+          token: Base64.encode64('sample-token'),
+          namespace: namespace
+        }
+      )
+
+      stub_kubeclient_put_secret(api_url, "#{namespace}-token", namespace: namespace)
+      stub_kubeclient_get_role_binding(api_url, "gitlab-#{namespace}", namespace: namespace)
+      stub_kubeclient_put_role_binding(api_url, "gitlab-#{namespace}", namespace: namespace)
+    end
+  end
+
+  describe 'POST /projects/:id/clusters/user' do
+    include_context 'kubernetes calls stubbed'
+
+    let(:api_url) { 'https://kubernetes.example.com' }
+    let(:namespace) { project.path }
+    let(:authorization_type) { 'rbac' }
+
+    let(:platform_kubernetes_attributes) do
+      {
+        api_url: api_url,
+        token: 'sample-token',
+        namespace: namespace,
+        authorization_type: authorization_type
+      }
+    end
+
+    let(:cluster_params) do
+      {
+        name: 'test-cluster',
+        platform_kubernetes_attributes: platform_kubernetes_attributes
+      }
+    end
+
+    context 'non-authorized user' do
+      it 'should respond with 404' do
+        post api("/projects/#{project.id}/clusters/user", non_member), params: cluster_params
+
+        expect(response).to have_gitlab_http_status(404)
+      end
+    end
+
+    context 'authorized user' do
+      before do
+        post api("/projects/#{project.id}/clusters/user", current_user), params: cluster_params
+      end
+
+      context 'with valid params' do
+        it 'should respond with 201' do
+          expect(response).to have_gitlab_http_status(201)
+        end
+
+        it 'should create a new Cluster::Cluster' do
+          cluster_result = Clusters::Cluster.find(json_response["id"])
+          platform_kubernetes = cluster_result.platform
+
+          expect(cluster_result).to be_user
+          expect(cluster_result).to be_kubernetes
+          expect(cluster_result.project).to eq(project)
+          expect(cluster_result.name).to eq('test-cluster')
+          expect(platform_kubernetes.rbac?).to be_truthy
+          expect(platform_kubernetes.api_url).to eq(api_url)
+          expect(platform_kubernetes.namespace).to eq(namespace)
+          expect(platform_kubernetes.token).to eq('sample-token')
+        end
+      end
+
+      context 'when user does not indicate authorization type' do
+        let(:platform_kubernetes_attributes) do
+          {
+            api_url: api_url,
+            token: 'sample-token',
+            namespace: namespace
+          }
+        end
+
+        it 'defaults to RBAC' do
+          cluster_result = Clusters::Cluster.find(json_response['id'])
+
+          expect(cluster_result.platform_kubernetes.rbac?).to be_truthy
+        end
+      end
+
+      context 'when user sets authorization type as ABAC' do
+        let(:authorization_type) { 'abac' }
+
+        it 'should create an ABAC cluster' do
+          cluster_result = Clusters::Cluster.find(json_response['id'])
+
+          expect(cluster_result.platform.abac?).to be_truthy
+        end
+      end
+
+      context 'with invalid params' do
+        let(:namespace) { 'invalid_namespace' }
+
+        it 'should respond with 400' do
+          expect(response).to have_gitlab_http_status(400)
+        end
+
+        it 'should not create a new Clusters::Cluster' do
+          expect(project.reload.clusters).to be_empty
+        end
+
+        it 'should return validation errors' do
+          expect(json_response['message']['platform_kubernetes.namespace'].first).to be_present
+        end
+      end
+    end
+  end
+
+  describe 'PUT /projects/:id/clusters/:cluster_id' do
+    include_context 'kubernetes calls stubbed'
+
+    let(:api_url) { 'https://kubernetes.example.com' }
+    let(:namespace) { 'new-namespace' }
+    let(:platform_kubernetes_attributes) { { namespace: namespace } }
+
+    let(:update_params) do
+      {
+        platform_kubernetes_attributes: platform_kubernetes_attributes
+      }
+    end
+
+    let!(:kubernetes_namespace) do
+      create(:cluster_kubernetes_namespace,
+             cluster: cluster,
+             project: project)
+    end
+
+    let(:cluster) do
+      create(:cluster, :project, :provided_by_gcp,
+             projects: [project])
+    end
+
+    context 'non-authorized user' do
+      it 'should respond with 404' do
+        put api("/projects/#{project.id}/clusters/#{cluster.id}", non_member), params: update_params
+
+        expect(response).to have_gitlab_http_status(404)
+      end
+    end
+
+    context 'authorized user' do
+      before do
+        put api("/projects/#{project.id}/clusters/#{cluster.id}", current_user), params: update_params
+
+        cluster.reload
+      end
+
+      context 'with valid params' do
+        it 'should respond with 200' do
+          expect(response).to have_gitlab_http_status(200)
+        end
+
+        it 'should update cluster attributes' do
+          expect(cluster.platform_kubernetes.namespace).to eq('new-namespace')
+          expect(cluster.kubernetes_namespace.namespace).to eq('new-namespace')
+        end
+      end
+
+      context 'with invalid params' do
+        let(:namespace) { 'invalid_namespace' }
+
+        it 'should respond with 400' do
+          expect(response).to have_gitlab_http_status(400)
+        end
+
+        it 'should not update cluster attributes' do
+          expect(cluster.platform_kubernetes.namespace).not_to eq('invalid_namespace')
+          expect(cluster.kubernetes_namespace.namespace).not_to eq('invalid_namespace')
+        end
+
+        it 'should return validation errors' do
+          expect(json_response['message']['platform_kubernetes.namespace'].first).to match('can contain only lowercase letters')
+        end
+      end
+
+      context 'with a GCP cluster' do
+        context 'when user tries to change GCP specific fields' do
+          let(:platform_kubernetes_attributes) do
+            {
+              api_url: 'https://new-api-url.com',
+              token: 'new-sample-token'
+            }
+          end
+
+          it 'should respond with 400' do
+            expect(response).to have_gitlab_http_status(400)
+          end
+
+          it 'should return validation error' do
+            expect(json_response['message']['platform_kubernetes.base'].first).to eq('Cannot modify managed Kubernetes cluster')
+          end
+        end
+
+        context 'when user tries to change namespace' do
+          let(:namespace) { 'new-namespace' }
+
+          it 'should respond with 200' do
+            expect(response).to have_gitlab_http_status(200)
+          end
+        end
+      end
+
+      context 'with an user cluster' do
+        let(:api_url) { 'https://new-api-url.com' }
+
+        let(:cluster) do
+          create(:cluster, :project, :provided_by_user,
+                 projects: [project])
+        end
+
+        let(:platform_kubernetes_attributes) do
+          {
+            api_url: api_url,
+            namespace: 'new-namespace',
+            token: 'new-sample-token'
+          }
+        end
+
+        let(:update_params) do
+          {
+            name: 'new-name',
+            platform_kubernetes_attributes: platform_kubernetes_attributes
+          }
+        end
+
+        it 'should respond with 200' do
+          expect(response).to have_gitlab_http_status(200)
+        end
+
+        it 'should update platform kubernetes attributes' do
+          platform_kubernetes = cluster.platform_kubernetes
+
+          expect(cluster.name).to eq('new-name')
+          expect(platform_kubernetes.namespace).to eq('new-namespace')
+          expect(platform_kubernetes.api_url).to eq('https://new-api-url.com')
+          expect(platform_kubernetes.token).to eq('new-sample-token')
+        end
+      end
+
+      context 'with a cluster that does not belong to user' do
+        let(:cluster) { create(:cluster, :project, :provided_by_user) }
+
+        it 'should respond with 404' do
+          expect(response).to have_gitlab_http_status(404)
+        end
+      end
+    end
+  end
+
+  describe 'DELETE /projects/:id/clusters/:cluster_id' do
+    let(:cluster_params) { { cluster_id: cluster.id } }
+
+    let(:cluster) do
+      create(:cluster, :project, :provided_by_gcp,
+             projects: [project])
+    end
+
+    context 'non-authorized user' do
+      it 'should respond with 404' do
+        delete api("/projects/#{project.id}/clusters/#{cluster.id}", non_member), params: cluster_params
+
+        expect(response).to have_gitlab_http_status(404)
+      end
+    end
+
+    context 'authorized user' do
+      before do
+        delete api("/projects/#{project.id}/clusters/#{cluster.id}", current_user), params: cluster_params
+      end
+
+      it 'should respond with 204' do
+        expect(response).to have_gitlab_http_status(204)
+      end
+
+      it 'should delete the cluster' do
+        expect(Clusters::Cluster.exists?(id: cluster.id)).to be_falsy
+      end
+
+      context 'with a cluster that does not belong to user' do
+        let(:cluster) { create(:cluster, :project, :provided_by_user) }
+
+        it 'should respond with 404' do
+          expect(response).to have_gitlab_http_status(404)
+        end
+      end
+    end
+  end
+end