Add API support for getting description templates

Closes https://gitlab.com/gitlab-org/gitlab/-/issues/23664

app/finders/template_finder.rb

@@ -7,7 +7,9 @@ class TemplateFinder
     dockerfiles: ::Gitlab::Template::DockerfileTemplate,
     gitignores: ::Gitlab::Template::GitignoreTemplate,
     gitlab_ci_ymls: ::Gitlab::Template::GitlabCiYmlTemplate,
-    metrics_dashboard_ymls: ::Gitlab::Template::MetricsDashboardTemplate
+    metrics_dashboard_ymls: ::Gitlab::Template::MetricsDashboardTemplate,
+    issues: ::Gitlab::Template::IssueTemplate,
+    merge_requests: ::Gitlab::Template::MergeRequestTemplate
   ).freeze
 
   class << self
@@ -35,9 +37,9 @@ class TemplateFinder
 
   def execute
     if params[:name]
-      vendored_templates.find(params[:name])
+      vendored_templates.find(params[:name], project)
     else
-      vendored_templates.all
+      vendored_templates.all(project)
     end
   end
 end

changelogs/unreleased/23664-description-templates-api.yml

+---
+title: Add API support for issue and merge request templates
+merge_request: 37890
+author: Jan Beckmann
+type: added

doc/api/project_templates.md

@@ -13,15 +13,15 @@ This API is a project-specific version of these endpoints:
 - [Gitignore templates](templates/gitignores.md)
 - [GitLab CI/CD Configuration templates](templates/gitlab_ci_ymls.md)
 - [Open source license templates](templates/licenses.md)
+- [Issue and merge request templates](../user/project/description_templates.md)
+  ([introduced](https://gitlab.com/gitlab-org/gitlab/-/merge_requests/37890) in GitLab 13.3 as a
+  community contribution)
 
 It deprecates these endpoints, which will be removed for API version 5.
 
 In addition to templates common to the entire instance, project-specific
 templates are also available from this API endpoint.
 
-Support will be added for [Issue and Merge Request templates](../user/project/description_templates.md)
-in a future release.
-
 Support for [Group-level file templates](../user/group/index.md#group-file-templates-premium)
 **(PREMIUM)** was [added](https://gitlab.com/gitlab-org/gitlab/-/issues/5987)
 in GitLab 11.5
@@ -35,7 +35,7 @@ GET /projects/:id/templates/:type
 | Attribute  | Type   | Required | Description |
 | ---------- | ------ | -------- | ----------- |
 | `id`      | integer / string | yes      | The ID or [URL-encoded path of the project](README.md#namespaced-path-encoding) |
-| `type`     | string | yes| The type `(dockerfiles|gitignores|gitlab_ci_ymls|licenses)` of the template |
+| `type`     | string | yes| The type `(dockerfiles|gitignores|gitlab_ci_ymls|licenses|issues|merge_requests)` of the template |
 
 Example response (licenses):
 
@@ -101,7 +101,7 @@ GET /projects/:id/templates/:type/:key
 | Attribute  | Type   | Required | Description |
 | ---------- | ------ | -------- | ----------- |
 | `id`      | integer / string | yes      | The ID or [URL-encoded path of the project](README.md#namespaced-path-encoding) |
-| `type`     | string | yes| The type `(dockerfiles|gitignores|gitlab_ci_ymls|licenses)` of the template |
+| `type`     | string | yes| The type `(dockerfiles|gitignores|gitlab_ci_ymls|licenses|issues|merge_requests)` of the template |
 | `key`      | string | yes      | The key of the template, as obtained from the collection endpoint |
 | `project`  | string | no       | The project name to use when expanding placeholders in the template. Only affects licenses |
 | `fullname` | string | no       | The full name of the copyright holder to use when expanding placeholders in the template. Only affects licenses |

ee/app/finders/ee/template_finder.rb

@@ -17,13 +17,15 @@ module EE
     def initialize(type, project, *args, &blk)
       super
 
-      finder = CUSTOM_TEMPLATES.fetch(type)
-      @custom_templates = ::Gitlab::CustomFileTemplates.new(finder, project)
+      if CUSTOM_TEMPLATES.key?(type)
+        finder = CUSTOM_TEMPLATES.fetch(type)
+        @custom_templates = ::Gitlab::CustomFileTemplates.new(finder, project)
+      end
     end
 
     override :execute
     def execute
-      return super unless custom_templates.enabled?
+      return super if custom_templates.nil? || !custom_templates.enabled?
 
       if params[:name]
         custom_templates.find(params[:name]) || super

lib/api/project_templates.rb

@@ -4,7 +4,7 @@ module API
   class ProjectTemplates < Grape::API::Instance
     include PaginationParams
 
-    TEMPLATE_TYPES = %w[dockerfiles gitignores gitlab_ci_ymls licenses metrics_dashboard_ymls].freeze
+    TEMPLATE_TYPES = %w[dockerfiles gitignores gitlab_ci_ymls licenses metrics_dashboard_ymls issues merge_requests].freeze
     # The regex is needed to ensure a period (e.g. agpl-3.0)
     # isn't confused with a format type. We also need to allow encoded
     # values (e.g. C%2B%2B for C++), so allow % and + as well.
@@ -14,7 +14,7 @@ module API
 
     params do
       requires :id, type: String, desc: 'The ID of a project'
-      requires :type, type: String, values: TEMPLATE_TYPES, desc: 'The type (dockerfiles|gitignores|gitlab_ci_ymls|licenses|metrics_dashboard_ymls) of the template'
+      requires :type, type: String, values: TEMPLATE_TYPES, desc: 'The type (dockerfiles|gitignores|gitlab_ci_ymls|licenses|metrics_dashboard_ymls|issues|merge_requests) of the template'
     end
     resource :projects, requirements: API::NAMESPACE_OR_PROJECT_REQUIREMENTS do
       desc 'Get a list of templates available to this project' do
@@ -42,9 +42,13 @@ module API
       end
 
       get ':id/templates/:type/:name', requirements: TEMPLATE_NAMES_ENDPOINT_REQUIREMENTS do
-        template = TemplateFinder
-          .build(params[:type], user_project, name: params[:name])
-          .execute
+        begin
+          template = TemplateFinder
+            .build(params[:type], user_project, name: params[:name])
+            .execute
+        rescue ::Gitlab::Template::Finders::RepoTemplateFinder::FileNotFoundError
+          not_found!('Template')
+        end
 
         not_found!('Template') unless template.present?
 

spec/requests/api/project_templates_spec.rb

@@ -3,8 +3,8 @@
 require 'spec_helper'
 
 RSpec.describe API::ProjectTemplates do
-  let_it_be(:public_project) { create(:project, :public, path: 'path.with.dot') }
-  let_it_be(:private_project) { create(:project, :private) }
+  let_it_be(:public_project) { create(:project, :public, :repository, create_templates: :merge_request, path: 'path.with.dot') }
+  let_it_be(:private_project) { create(:project, :private, :repository, create_templates: :issue) }
   let_it_be(:developer) { create(:user) }
 
   let(:url_encoded_path) { "#{public_project.namespace.path}%2F#{public_project.path}" }
@@ -71,6 +71,24 @@ RSpec.describe API::ProjectTemplates do
       expect(json_response).to satisfy_one { |template| template['key'] == 'Default' }
     end
 
+    it 'returns issue templates' do
+      get api("/projects/#{private_project.id}/templates/issues", developer)
+
+      expect(response).to have_gitlab_http_status(:ok)
+      expect(response).to include_pagination_headers
+      expect(response).to match_response_schema('public_api/v4/template_list')
+      expect(json_response.map {|t| t['key']}).to match_array(%w(bug feature_proposal template_test))
+    end
+
+    it 'returns merge request templates' do
+      get api("/projects/#{public_project.id}/templates/merge_requests")
+
+      expect(response).to have_gitlab_http_status(:ok)
+      expect(response).to include_pagination_headers
+      expect(response).to match_response_schema('public_api/v4/template_list')
+      expect(json_response.map {|t| t['key']}).to match_array(%w(bug feature_proposal template_test))
+    end
+
     it 'returns 400 for an unknown template type' do
       get api("/projects/#{public_project.id}/templates/unknown")
 
@@ -160,12 +178,42 @@ RSpec.describe API::ProjectTemplates do
       expect(response).to match_response_schema('public_api/v4/license')
     end
 
+    it 'returns a specific issue template' do
+      get api("/projects/#{private_project.id}/templates/issues/bug", developer)
+
+      expect(response).to have_gitlab_http_status(:ok)
+      expect(response).to match_response_schema('public_api/v4/template')
+      expect(json_response['name']).to eq('bug')
+      expect(json_response['content']).to eq('something valid')
+    end
+
+    it 'returns a specific merge request template' do
+      get api("/projects/#{public_project.id}/templates/merge_requests/feature_proposal")
+
+      expect(response).to have_gitlab_http_status(:ok)
+      expect(response).to match_response_schema('public_api/v4/template')
+      expect(json_response['name']).to eq('feature_proposal')
+      expect(json_response['content']).to eq('feature_proposal') # Content is identical to filename here
+    end
+
     it 'returns 404 for an unknown specific template' do
       get api("/projects/#{public_project.id}/templates/licenses/unknown")
 
       expect(response).to have_gitlab_http_status(:not_found)
     end
 
+    it 'returns 404 for an unknown issue template' do
+      get api("/projects/#{public_project.id}/templates/issues/unknown")
+
+      expect(response).to have_gitlab_http_status(:not_found)
+    end
+
+    it 'returns 404 for an unknown merge request template' do
+      get api("/projects/#{public_project.id}/templates/merge_requests/unknown")
+
+      expect(response).to have_gitlab_http_status(:not_found)
+    end
+
     it 'denies access to an anonymous user on a private project' do
       get api("/projects/#{private_project.id}/templates/licenses/mit")