Expose DDF schema for a provider when asking using OPTIONS + type

app/controllers/api/providers_controller.rb

@@ -84,24 +84,9 @@ def import_vm_resource(type, id = nil, data = {})
     end
 
     def options
-      providers_options = ManageIQ::Providers::BaseManager.leaf_subclasses.inject({}) do |po, ems|
-        po.merge(ems.ems_type => ems.options_description)
-      end
-
-      supported_providers = ExtManagementSystem.supported_types_for_create.map do |klass|
-        if klass.supports_regions?
-          regions = klass.parent::Regions.all.sort_by { |r| r[:description] }.map { |r| r.slice(:name, :description) }
-        end
-
-        {
-          :title   => klass.description,
-          :type    => klass.to_s,
-          :kind    => klass.to_s.demodulize.sub(/Manager$/, '').underscore,
-          :regions => regions
-        }.compact
-      end
-
-      render_options(:providers, "provider_settings" => providers_options, "supported_providers" => supported_providers)
+      options = providers_options
+      options['provider_form_schema'] = provider_options(params[:type]) if params[:type]
+      render_options(:providers, options)
     end
 
     def pause_resource(type, id, _data)
@@ -131,6 +116,36 @@ def change_password_resource(type, id, data = {})
 
     private
 
+    def provider_options(type)
+      klass = type.safe_constantize
+
+      raise BadRequestError, "Invalid provider - #{type}" unless klass.try(:<, ExtManagementSystem)
+      raise BadRequestError, "No DDF specified for - #{type}" unless klass.respond_to?(:params_for_create)
+
+      klass.params_for_create
+    end
+
+    def providers_options
+      providers_options = ManageIQ::Providers::BaseManager.leaf_subclasses.inject({}) do |po, ems|
+        po.merge(ems.ems_type => ems.options_description)
+      end
+
+      supported_providers = ExtManagementSystem.supported_types_for_create.map do |klass|
+        if klass.supports_regions?
+          regions = klass.parent::Regions.all.sort_by { |r| r[:description] }.map { |r| r.slice(:name, :description) }
+        end
+
+        {
+          :title   => klass.description,
+          :type    => klass.to_s,
+          :kind    => klass.to_s.demodulize.sub(/Manager$/, '').underscore,
+          :regions => regions
+        }.compact
+      end
+
+      { "provider_settings" => providers_options, "supported_providers" => supported_providers }
+    end
+
     # Process password change request for a single resource
     #
     # @raise [BadRequestError] if no id is passed or some required data is missing

spec/requests/providers_spec.rb

@@ -1588,6 +1588,31 @@ def gen_import_request
       )
       expect(response.parsed_body["data"]["provider_settings"]["kubernetes"]["proxy_settings"]["settings"]["http_proxy"]["label"]).to eq('HTTP Proxy')
     end
+
+    context 'single provider queried' do
+      it 'raises an error if the provider is invalid' do
+        options("#{api_providers_url}?type=foo")
+        expect_bad_request("Invalid provider - foo")
+      end
+
+      context 'valid provider' do
+        before do
+          class DummyProvider; end
+          allow(DummyProvider).to receive(:<).with(ExtManagementSystem).and_return(true)
+        end
+
+        it 'raises an error if the provider has no DDF' do
+          options("#{api_providers_url}?type=DummyProvider")
+          expect_bad_request("No DDF specified for - DummyProvider")
+        end
+
+        it 'calls the .params_for_create on the provider' do
+          expect(DummyProvider).to receive(:params_for_create).and_return('foo' => 'bar')
+          options("#{api_providers_url}?type=DummyProvider")
+          expect(response.parsed_body['data']['provider_form_schema']).to eq('foo' => 'bar')
+        end
+      end
+    end
   end
 
   context 'GET /api/providers/:id/vms' do