CHEF-7670 Ability to set feature preview flag using ENV (#6833)

* Implemented ability to add feature flags in Inspec feature subsystem

Signed-off-by: Nik08 <nikita.mathur@progress.com>

* Added usage of env_preview for conditionalising features

Signed-off-by: Nik08 <nikita.mathur@progress.com>

* Test cases added for feature preview flag ability

Signed-off-by: Nik08 <nikita.mathur@progress.com>

* Minor chnages - Better commenting & smarter methods

Signed-off-by: Nik08 <nikita.mathur@progress.com>

---------

Signed-off-by: Nik08 <nikita.mathur@progress.com>

lib/inspec/feature.rb

@@ -7,11 +7,28 @@ module Inspec
   end
 
   class Feature
-    attr_reader :name, :description
+    attr_reader :name, :description, :env_preview
     def initialize(feature_name, feature_yaml_opts)
       @name = feature_name
       feature_yaml_opts ||= {}
       @description = feature_yaml_opts["description"]
+      @env_preview = feature_yaml_opts["env_preview"]
+    end
+
+    def previewable?
+      # If the feature is previewable in config (features.yaml) & has an environment value set to use previewed feature
+      !!env_preview && !env_preview_value.nil?
+    end
+
+    def no_preview?
+      env_preview.nil?
+    end
+
+    def env_preview_value
+      # Examples: If feature name is "inspec-test-feature"
+      # ENV used for this feature preview would be CHEF_PREVIEW_TEST_FEATURE
+      env_preview_feature_name = name.to_s.split("inspec-")[-1]
+      ENV["CHEF_PREVIEW_#{env_preview_feature_name.gsub("-", "_").upcase}"]
     end
   end
 end

lib/inspec/feature/runner.rb

@@ -14,7 +14,12 @@ module Inspec
           logger.warn "Unrecognized feature name '#{feature_name}'"
         end
 
-        yield feature_implementation
+        # If the feature is not recognized
+        # If the feature has no env_preview flag set in config
+        # If the feature is previewable
+        if feature.nil? || feature&.no_preview? || feature&.previewable?
+          yield feature_implementation
+        end
       end
     end
   end

test/fixtures/features-02.sig

@@ -0,0 +1,6 @@
+zLNcjwWCxg642VkKw7lOANqmzHHI38Ro0v3+CFuFjpQTIGUiPsNFKj6Jpza7
+LpdvDVpRw2yBy46h+M/49/4PA2DDLpiT2M3QCkViQoF2Ue5FgAOsqwUuEhYr
+PoxtihyJmJVfMsRUuxmaiquYYjESvm1pPV5kP06BeZpwhPXuKc18m5KxN5yU
+VxqWi/RlejpNe2BJSW24kfdqhEYCDRFZ4A01OvjARritVciGYMX7tfcDT7yP
+2ogLxEXBFNItzHw/zAUykL9V0uEquiG4WfDc+94Iw6srbKiZWkr5bc+WnVT0
+6MhUM+xrTlxt38mHoPI2yxNqjDb2Adah0MGq++Bd3w==

test/fixtures/features-02.yaml

@@ -0,0 +1,13 @@
+---
+  features:
+    inspec-test-feature-01:
+      description: Fun for the whole security organization
+      env_preview: true
+    inspec-test-feature-02:
+      description: Fun for the whole security organization
+      env_preview: true
+    inspec-test-feature-03:
+      description: A great use of your time
+      env_preview: false
+    inspec-test-feature-04:
+      description: A great use of your time and also fun

test/unit/feature_test.rb

@@ -130,5 +130,66 @@ describe "Inspec::Feature" do
         _ { Inspec::Feature::Config.new(tampered_config_file) }.must_raise(Inspec::FeatureConfigTamperedError)
       end
     end
+
+    describe "When using feature preview flag" do
+      let(:feature_config_file) { File.join(fixtures_path, "features-02.yaml") }
+      # you should be able to load it from a test file
+      let(:cfg) { Inspec::Feature::Config.new(feature_config_file) }
+
+      before do
+        # Setting ENV value for test feature 1
+        ENV["CHEF_PREVIEW_TEST_FEATURE_01"] = "1"
+      end
+      after do
+        ENV.delete("CHEF_PREVIEW_TEST_FEATURE_01")
+      end
+
+      it "yields block only when previewable and ENV value is set" do
+        test_feature_01 = cfg.features[0]
+        test_feature_01_called = false
+        Inspec.with_feature("inspec-test-feature-01", config: cfg) do
+          test_feature_01_called = true
+        end
+        _(test_feature_01_called).must_equal true
+        _(test_feature_01.previewable?).must_equal true
+      end
+
+      it "does not yields block when preview_env true but ENV value is not set" do
+        test_feature_02 = cfg.features[1]
+        test_feature_02_called = false
+        Inspec.with_feature("inspec-test-feature-02", config: cfg) do
+          test_feature_02_called = true
+        end
+        _(test_feature_02_called).must_equal false
+        _(test_feature_02.previewable?).must_equal false
+      end
+
+      it "does not yields block when not previewable" do
+        test_feature_03 = cfg.features[2]
+        test_feature_03_called = false
+        Inspec.with_feature("inspec-test-feature-03", config: cfg) do
+          test_feature_03_called = true
+        end
+        _(test_feature_03_called).must_equal false
+        _(test_feature_03.previewable?).must_equal false
+      end
+    end
+
+    describe "When not using feature preview flag" do
+      let(:feature_config_file) { File.join(fixtures_path, "features-02.yaml") }
+      # you should be able to load it from a test file
+      let(:cfg) { Inspec::Feature::Config.new(feature_config_file) }
+
+      it "yields block when flag not set" do
+        test_feature_04 = cfg.features[3]
+        test_feature_04_called = false
+        Inspec.with_feature("inspec-test-feature-04", config: cfg) do
+          test_feature_04_called = true
+        end
+        _(test_feature_04_called).must_equal true
+        _(test_feature_04.previewable?).must_equal false
+        _(test_feature_04.no_preview?).must_equal true
+      end
+    end
   end
 end