Allow feature gate removal through the APIzj-feature-gate-remove-http-api

Features could be listed and added through the api, now also removed.
This was needed in the case of gitlab.com as the number of gates that
were ever used just grows and cleaning up is hard.

4 files changed, 61 insertions, 2 deletions

diff --git a/changelogs/unreleased/zj-feature-gate-remove-http-api.yml b/changelogs/unreleased/zj-feature-gate-remove-http-api.yml
new file mode 100644
index 00000000000..2095f60146c
--- /dev/null
+++ b/changelogs/unreleased/zj-feature-gate-remove-http-api.yml
@@ -0,0 +1,5 @@
+---
+title: Allow feature gates to be removed through the API
+merge_request:
+author:
+type: added
diff --git a/doc/api/features.md b/doc/api/features.md
index 6861dbf00a2..6ee1c36ef5b 100644
--- a/doc/api/features.md
+++ b/doc/api/features.md
@@ -86,3 +86,11 @@ Example response:
   ]
 }
 ```
+
+## Delete a feature
+
+Removes a feature gate. Response is equal when the gate exists, or doesn't.
+
+```
+DELETE /features/:name
+```
diff --git a/lib/api/features.rb b/lib/api/features.rb
index 9385c6ca174..11d848584d9 100644
--- a/lib/api/features.rb
+++ b/lib/api/features.rb
@@ -65,6 +65,13 @@ module API
 
         present feature, with: Entities::Feature, current_user: current_user
       end
+
+      desc 'Remove the gate value for the given feature'
+      delete ':name' do
+        Feature.get(params[:name]).remove
+
+        status 204
+      end
     end
   end
 end
diff --git a/spec/requests/api/features_spec.rb b/spec/requests/api/features_spec.rb
index 267058d98ee..c5354c2d639 100644
--- a/spec/requests/api/features_spec.rb
+++ b/spec/requests/api/features_spec.rb
@@ -1,8 +1,8 @@
 require 'spec_helper'
 
 describe API::Features do
-  let(:user)  { create(:user) }
-  let(:admin) { create(:admin) }
+  set(:user)  { create(:user) }
+  set(:admin) { create(:admin) }
 
   before do
     Flipper.unregister_groups
@@ -249,4 +249,43 @@ describe API::Features do
       end
     end
   end
+
+  describe 'DELETE /feature/:name' do
+    let(:feature_name) { 'my_feature' }
+
+    context 'when the user has no access' do
+      it 'returns a 401 for anonymous users' do
+        delete api("/features/#{feature_name}")
+
+        expect(response).to have_gitlab_http_status(401)
+      end
+
+      it 'returns a 403 for users' do
+        delete api("/features/#{feature_name}", user)
+
+        expect(response).to have_gitlab_http_status(403)
+      end
+    end
+
+    context 'when the user has access' do
+      it 'returns 204 when the value is not set' do
+        delete api("/features/#{feature_name}", admin)
+
+        expect(response).to have_gitlab_http_status(204)
+      end
+
+      context 'when the gate value was set' do
+        before do
+          Feature.get(feature_name).enable
+        end
+
+        it 'deletes an enabled feature' do
+          delete api("/features/#{feature_name}", admin)
+
+          expect(response).to have_gitlab_http_status(204)
+          expect(Feature.get(feature_name)).not_to be_enabled
+        end
+      end
+    end
+  end
 end