Add management_project_id to POST API, fix docs

The docs for the POST method mention management_project_id but it was
not supported, so we added it to the code.

Conversely, docs for the PUT method were missing management_project_id,
when it was in fact supported, so we added it to the docs.

changelogs/unreleased/211998-add-cluster-mangement-id-on-create.yml

+---
+title: Add management_project_id to group and project cluster creation, clarifies
+  docs.
+merge_request: 28289
+author:
+type: fixed

doc/api/group_clusters.md

@@ -224,6 +224,7 @@ Parameters:
 | `cluster_id` | integer | yes | The ID of the cluster |
 | `name` | string | no | The name of the cluster |
 | `domain` | string | no | The [base domain](../user/group/clusters/index.md#base-domain) of the cluster |
+| `management_project_id` | integer | no | The ID of the [management project](../user/clusters/management_project.md) for the cluster |
 | `platform_kubernetes_attributes[api_url]` | string | no | The URL to access the Kubernetes API |
 | `platform_kubernetes_attributes[token]` | string | no | The token to authenticate against Kubernetes |
 | `platform_kubernetes_attributes[ca_cert]` | string | no | TLS certificate. Required if API is using a self-signed TLS certificate. |

doc/api/project_clusters.md

@@ -179,6 +179,7 @@ Parameters:
 | `id` | integer | yes | The ID of the project owned by the authenticated user |
 | `name` | string | yes | The name of the cluster |
 | `domain` | string | no | The [base domain](../user/project/clusters/index.md#base-domain) of the cluster |
+| `management_project_id` | integer | no | The ID of the [management project](../user/clusters/management_project.md) for the cluster |
 | `enabled` | boolean | no | Determines if cluster is active or not, defaults to true |
 | `managed` | boolean | no | Determines if GitLab will manage namespaces and service accounts for this cluster, defaults to true |
 | `platform_kubernetes_attributes[api_url]` | string | yes | The URL to access the Kubernetes API |

lib/api/group_clusters.rb

@@ -53,6 +53,7 @@ module API
         requires :name, type: String, desc: 'Cluster name'
         optional :enabled, type: Boolean, default: true, desc: 'Determines if cluster is active or not, defaults to true'
         optional :domain, type: String, desc: 'Cluster base domain'
+        optional :management_project_id, type: Integer, desc: 'The ID of the management project'
         optional :managed, type: Boolean, default: true, desc: 'Determines if GitLab will manage namespaces and service accounts for this cluster, 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'

lib/api/project_clusters.rb

@@ -56,6 +56,7 @@ module API
         requires :name, type: String, desc: 'Cluster name'
         optional :enabled, type: Boolean, default: true, desc: 'Determines if cluster is active or not, defaults to true'
         optional :domain, type: String, desc: 'Cluster base domain'
+        optional :management_project_id, type: Integer, desc: 'The ID of the management project'
         optional :managed, type: Boolean, default: true, desc: 'Determines if GitLab will manage namespaces and service accounts for this cluster, 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'

spec/requests/api/group_clusters_spec.rb

@@ -157,6 +157,8 @@ describe API::GroupClusters do
 
     let(:api_url) { 'https://kubernetes.example.com' }
     let(:authorization_type) { 'rbac' }
+    let(:management_project) { create(:project, group: group) }
+    let(:management_project_id) { management_project.id }
 
     let(:platform_kubernetes_attributes) do
       {
@@ -171,7 +173,8 @@ describe API::GroupClusters do
         name: 'test-cluster',
         domain: 'domain.example.com',
         managed: false,
-        platform_kubernetes_attributes: platform_kubernetes_attributes
+        platform_kubernetes_attributes: platform_kubernetes_attributes,
+        management_project_id: management_project_id
       }
     end
 

spec/requests/api/project_clusters_spec.rb

@@ -150,6 +150,8 @@ describe API::ProjectClusters do
     let(:api_url) { 'https://kubernetes.example.com' }
     let(:namespace) { project.path }
     let(:authorization_type) { 'rbac' }
+    let(:management_project) { create(:project, namespace: project.namespace) }
+    let(:management_project_id) { management_project.id }
 
     let(:platform_kubernetes_attributes) do
       {
@@ -165,7 +167,8 @@ describe API::ProjectClusters do
         name: 'test-cluster',
         domain: 'domain.example.com',
         managed: false,
-        platform_kubernetes_attributes: platform_kubernetes_attributes
+        platform_kubernetes_attributes: platform_kubernetes_attributes,
+        management_project_id: management_project_id
       }
     end