Add feature toggles through Flipper

4 files changed, 213 insertions, 2 deletions

diff --git a/spec/lib/feature_spec.rb b/spec/lib/feature_spec.rb
new file mode 100644
index 00000000000..1d92a5cb33f
--- /dev/null
+++ b/spec/lib/feature_spec.rb
@@ -0,0 +1,26 @@
+require 'spec_helper'
+
+describe Feature, lib: true do
+  describe '.get' do
+    let(:feature) { double(:feature) }
+    let(:key) { 'my_feature' }
+
+    it 'returns the Flipper feature' do
+      expect_any_instance_of(Flipper::DSL).to receive(:feature).with(key).
+        and_return(feature)
+
+      expect(described_class.get(key)).to be(feature)
+    end
+  end
+
+  describe '.all' do
+    let(:features) { Set.new }
+
+    it 'returns the Flipper features as an array' do
+      expect_any_instance_of(Flipper::DSL).to receive(:features).
+        and_return(features)
+
+      expect(described_class.all).to eq(features.to_a)
+    end
+  end
+end
diff --git a/spec/lib/gitlab/gitaly_client_spec.rb b/spec/lib/gitlab/gitaly_client_spec.rb
index 08ee0dff6b2..95ecba67532 100644
--- a/spec/lib/gitlab/gitaly_client_spec.rb
+++ b/spec/lib/gitlab/gitaly_client_spec.rb
@@ -1,7 +1,10 @@
 require 'spec_helper'
 
-describe Gitlab::GitalyClient, lib: true do
+# We stub Gitaly in `spec/support/gitaly.rb` for other tests. We don't want
+# those stubs while testing the GitalyClient itself.
+describe Gitlab::GitalyClient, lib: true, skip_gitaly_mock: true do
   describe '.stub' do
+    # Notice that this is referring to gRPC "stubs", not rspec stubs
     before { described_class.clear_stubs! }
 
     context 'when passed a UNIX socket address' do
@@ -32,4 +35,81 @@ describe Gitlab::GitalyClient, lib: true do
       end
     end
   end
+
+  describe 'feature_enabled?' do
+    let(:feature_name) { 'my_feature' }
+    let(:real_feature_name) { "gitaly_#{feature_name}" }
+
+    context 'when Gitaly is disabled' do
+      before { allow(described_class).to receive(:enabled?).and_return(false) }
+
+      it 'returns false' do
+        expect(described_class.feature_enabled?(feature_name)).to be(false)
+      end
+    end
+
+    context 'when the feature status is DISABLED' do
+      let(:feature_status) { Gitlab::GitalyClient::MigrationStatus::DISABLED }
+
+      it 'returns false' do
+        expect(described_class.feature_enabled?(feature_name, status: feature_status)).to be(false)
+      end
+    end
+
+    context 'when the feature_status is OPT_IN' do
+      let(:feature_status) { Gitlab::GitalyClient::MigrationStatus::OPT_IN }
+
+      context "when the feature flag hasn't been set" do
+        it 'returns false' do
+          expect(described_class.feature_enabled?(feature_name, status: feature_status)).to be(false)
+        end
+      end
+
+      context "when the feature flag is set to disable" do
+        before { Feature.get(real_feature_name).disable }
+
+        it 'returns false' do
+          expect(described_class.feature_enabled?(feature_name, status: feature_status)).to be(false)
+        end
+      end
+
+      context "when the feature flag is set to enable" do
+        before { Feature.get(real_feature_name).enable }
+
+        it 'returns true' do
+          expect(described_class.feature_enabled?(feature_name, status: feature_status)).to be(true)
+        end
+      end
+
+      context "when the feature flag is set to a percentage of time" do
+        before { Feature.get(real_feature_name).enable_percentage_of_time(70) }
+
+        it 'bases the result on pseudo-random numbers' do
+          expect(Random).to receive(:rand).and_return(0.3)
+          expect(described_class.feature_enabled?(feature_name, status: feature_status)).to be(true)
+
+          expect(Random).to receive(:rand).and_return(0.8)
+          expect(described_class.feature_enabled?(feature_name, status: feature_status)).to be(false)
+        end
+      end
+    end
+
+    context 'when the feature_status is OPT_OUT' do
+      let(:feature_status) { Gitlab::GitalyClient::MigrationStatus::OPT_OUT }
+
+      context "when the feature flag hasn't been set" do
+        it 'returns true' do
+          expect(described_class.feature_enabled?(feature_name, status: feature_status)).to be(true)
+        end
+      end
+
+      context "when the feature flag is set to disable" do
+        before { Feature.get(real_feature_name).disable }
+
+        it 'returns false' do
+          expect(described_class.feature_enabled?(feature_name, status: feature_status)).to be(false)
+        end
+      end
+    end
+  end
 end
diff --git a/spec/requests/api/features_spec.rb b/spec/requests/api/features_spec.rb
new file mode 100644
index 00000000000..f169e6661d1
--- /dev/null
+++ b/spec/requests/api/features_spec.rb
@@ -0,0 +1,104 @@
+require 'spec_helper'
+
+describe API::Features do
+  let(:user)  { create(:user) }
+  let(:admin) { create(:admin) }
+
+  describe 'GET /features' do
+    let(:expected_features) do
+      [
+        {
+          'name' => 'feature_1',
+          'state' => 'on',
+          'gates' => [{ 'key' => 'boolean', 'value' => true }]
+        },
+        {
+          'name' => 'feature_2',
+          'state' => 'off',
+          'gates' => [{ 'key' => 'boolean', 'value' => false }]
+        }
+      ]
+    end
+
+    before do
+      Feature.get('feature_1').enable
+      Feature.get('feature_2').disable
+    end
+
+    it 'returns a 401 for anonymous users' do
+      get api('/features')
+
+      expect(response).to have_http_status(401)
+    end
+
+    it 'returns a 403 for users' do
+      get api('/features', user)
+
+      expect(response).to have_http_status(403)
+    end
+
+    it 'returns the feature list for admins' do
+      get api('/features', admin)
+
+      expect(response).to have_http_status(200)
+      expect(json_response).to match_array(expected_features)
+    end
+  end
+
+  describe 'POST /feature' do
+    let(:feature_name) { 'my_feature' }
+    it 'returns a 401 for anonymous users' do
+      post api("/features/#{feature_name}")
+
+      expect(response).to have_http_status(401)
+    end
+
+    it 'returns a 403 for users' do
+      post api("/features/#{feature_name}", user)
+
+      expect(response).to have_http_status(403)
+    end
+
+    it 'creates an enabled feature if passed true' do
+      post api("/features/#{feature_name}", admin), value: 'true'
+
+      expect(response).to have_http_status(201)
+      expect(Feature.get(feature_name)).to be_enabled
+    end
+
+    it 'creates a feature with the given percentage if passed an integer' do
+      post api("/features/#{feature_name}", admin), value: '50'
+
+      expect(response).to have_http_status(201)
+      expect(Feature.get(feature_name).percentage_of_time_value).to be(50)
+    end
+
+    context 'when the feature exists' do
+      let(:feature) { Feature.get(feature_name) }
+
+      before do
+        feature.disable # This also persists the feature on the DB
+      end
+
+      it 'enables the feature if passed true' do
+        post api("/features/#{feature_name}", admin), value: 'true'
+
+        expect(response).to have_http_status(201)
+        expect(feature).to be_enabled
+      end
+
+      context 'with a pre-existing percentage value' do
+        before do
+          feature.enable_percentage_of_time(50)
+        end
+
+        it 'updates the percentage of time if passed an integer' do
+          post api("/features/#{feature_name}", admin), value: '30'
+
+          expect(response).to have_http_status(201)
+          expect(Feature.get(feature_name).percentage_of_time_value).to be(30)
+        end
+      end
+    end
+  end
+end
diff --git a/spec/support/gitaly.rb b/spec/support/gitaly.rb
index 7aca902fc61..2bf159002a0 100644
--- a/spec/support/gitaly.rb
+++ b/spec/support/gitaly.rb
@@ -1,6 +1,7 @@
 if Gitlab::GitalyClient.enabled?
   RSpec.configure do |config|
-    config.before(:each) do
+    config.before(:each) do |example|
+      next if example.metadata[:skip_gitaly_mock]
       allow(Gitlab::GitalyClient).to receive(:feature_enabled?).and_return(true)
     end
   end