feat(spec): Add API implementation

.github/workflows/main.yml

@@ -26,54 +26,9 @@ jobs:
       - uses: ruby/setup-ruby@v1
         with:
           ruby-version: ${{ matrix.ruby }}
-          bundler-cache: true
       - run: bundle install
       - run: bundle exec rake
-
-  rubocop:
-    runs-on: ${{ matrix.os }}
-    name: Rubocop ${{ matrix.ruby }}
-    strategy:
-      fail-fast: false
-      matrix:
-        os: [ubuntu-latest, macos-latest, windows-latest]
-        ruby:
-          - "3.1.2"
-          - "2.7.6"
-          - "3.0.4"
-    env:
-      BUNDLE_GEMFILE: Gemfile
-
-    steps:
-      - uses: actions/checkout@v3
-      - name: Set up Ruby ${{ matrix.ruby }}
-        uses: ruby/setup-ruby@v1
-        with:
-          ruby-version: ${{ matrix.ruby }}
-          bundler-cache: true
       - name: Run style checks
         run: bundle exec rubocop
-
-  test:
-    runs-on: ${{ matrix.os }}
-    name: RSpec ${{ matrix.ruby }}
-    strategy:
-      fail-fast: false
-      matrix:
-        os: [ubuntu-latest, macos-latest, windows-latest]
-        ruby:
-          - "3.1.2"
-          - "2.7.6"
-          - "3.0.4"
-    env:
-      BUNDLE_GEMFILE: Gemfile
-
-    steps:
-      - uses: actions/checkout@v3
-      - name: Set up Ruby ${{ matrix.ruby }}
-        uses: ruby/setup-ruby@v1
-        with:
-          ruby-version: ${{ matrix.ruby }}
-          bundler-cache: true
       - name: Run tests
         run: bundle exec rspec

.rspec

@@ -1,3 +1,4 @@
+-I lib
 --format documentation
 --color
 --require spec_helper

.rubocop.yml

@@ -12,6 +12,13 @@ Style/StringLiteralsInInterpolation:
 
 Layout/LineLength:
   Max: 120
+  Exclude:
+    - 'spec/**/*.rb'
+
+Metrics/BlockLength:
+  Exclude:
+    - 'spec/**/*.rb'
+    - 'openfeature-sdk.gemspec'
 
 Gemspec/RequireMFA:
   Enabled: false

Gemfile

@@ -4,3 +4,5 @@ source "https://rubygems.org"
 
 # Specify your gem's dependencies in openfeature-sdk.gemspec
 gemspec
+
+gem "concurrent-ruby", require: "concurrent"

Gemfile.lock

@@ -1,12 +1,13 @@
 PATH
   remote: .
   specs:
-    openfeature-sdk (0.0.2)
+    openfeature-sdk (0.0.3)
 
 GEM
   remote: https://rubygems.org/
   specs:
     ast (2.4.2)
+    concurrent-ruby (1.1.10)
     diff-lcs (1.5.0)
     json (2.6.2)
     parallel (1.22.1)
@@ -55,6 +56,7 @@ PLATFORMS
   x86_64-linux
 
 DEPENDENCIES
+  concurrent-ruby
   openfeature-sdk!
   rake (~> 13.0)
   rspec (~> 3.12.0)

lib/openfeature/sdk.rb

@@ -1,10 +1,11 @@
 # frozen_string_literal: true
 
 require_relative "sdk/version"
+require_relative "sdk/api"
 
 module OpenFeature
+  # TODO: Add documentation
+  #
   module SDK
-    class Error < StandardError; end
-    # Your code goes here...
   end
 end

lib/openfeature/sdk/api.rb

@@ -0,0 +1,53 @@
+# frozen_string_literal: true
+
+require "forwardable"
+require "singleton"
+
+require_relative "configuration"
+require_relative "client"
+require_relative "metadata"
+require_relative "provider/no_op_provider"
+
+module OpenFeature
+  module SDK
+    # API Initialization and Configuration
+    #
+    # Represents the entry point to the API, including configuration of <tt>Provider</tt>,<tt>Hook</tt>,
+    # and building the <tt>Client</tt>
+    #
+    # To use the SDK, you can optionally configure a <tt>Provider</tt>, with <tt>Hook</tt>
+    #
+    #   OpenFeature::SDK::API.instance.configure do |config|
+    #     config.provider = NoOpProvider.new
+    #   end
+    #
+    # If no provider is specified, the <tt>NoOpProvider</tt> is set as the default <tt>Provider</tt>.
+    # Once the SDK has been configured, a client can be built
+    #
+    #   client = OpenFeature::SDK::API.instance.build_client(name: 'my-open-feature-client')
+    class API
+      include Singleton
+      extend Forwardable
+
+      def_delegator :@configuration, :provider
+      def_delegator :@configuration, :hooks
+      def_delegator :@configuration, :context
+
+      def configuration
+        @configuration ||= Configuration.new
+      end
+
+      def configure(&block)
+        return unless block_given?
+
+        block.call(configuration)
+      end
+
+      def build_client(name: nil, version: nil)
+        client_options = Metadata.new(name: name, version: version).freeze
+        provider = Provider::NoOpProvider.new if provider.nil?
+        Client.new(provider, client_options, context)
+      end
+    end
+  end
+end

lib/openfeature/sdk/client.rb

@@ -0,0 +1,19 @@
+# frozen_string_literal: true
+
+module OpenFeature
+  module SDK
+    # TODO: Write documentation
+    #
+    class Client
+      attr_reader :metadata
+
+      attr_accessor :hooks
+
+      def initialize(provider, client_options, context)
+        @provider = provider
+        @client_options = client_options
+        @context = context
+      end
+    end
+  end
+end

lib/openfeature/sdk/configuration.rb

@@ -0,0 +1,25 @@
+# frozen_string_literal: true
+
+require "concurrent"
+
+require_relative "api"
+
+module OpenFeature
+  module SDK
+    # Represents the configuration object for the global API where <tt>Provider</tt>, <tt>Hook</tt>,
+    # and <tt>Context</tt> are configured.
+    # This class is not meant to be interacted with directly but instead through the <tt>OpenFeature::SDK.configure</tt>
+    # method
+    class Configuration
+      extend Forwardable
+
+      attr_accessor :context, :provider, :hooks
+
+      def_delegator :@provider, :metadata
+
+      def initialize
+        @hooks = Concurrent::Array.new([])
+      end
+    end
+  end
+end

lib/openfeature/sdk/metadata.rb

@@ -0,0 +1,35 @@
+# frozen_string_literal: true
+
+module OpenFeature
+  module SDK
+    # Metadata structure that defines general metadata relating to a <tt>Provider</tt> or <tt>Client</tt>
+    #
+    # Within the Metadata structure, the following attribute readers are available:
+    #
+    # * <tt>name</tt> - Defines the name of the structure
+    #
+    # * <tt>version</tt> - Allows you to specify version of the Metadata structure
+    #
+    # Usage:
+    #
+    #   metadata = Metadata.new(name: 'name-for-metadata', version: 'v1.1.3')
+    #   metadata.name # 'name-for-metadata'
+    #   metadata.version # version
+    #   metadata_two = Metadata.new(name: 'name-for-metadata')
+    #   metadata_two == metadata # true - equality based on values
+    class Metadata
+      attr_reader :name, :version
+
+      def initialize(name:, version: nil)
+        @name = name
+        @version = version
+      end
+
+      def ==(other)
+        raise ArgumentError("Expected comparison to be between Metadata object") unless other.is_a?(Metadata)
+
+        @name == other.name && @version == other.version
+      end
+    end
+  end
+end

lib/openfeature/sdk/provider/no_op_provider.rb

@@ -0,0 +1,62 @@
+# frozen_string_literal: true
+
+require_relative "../metadata"
+
+# rubocop:disable Lint/UnusedMethodArgument
+module OpenFeature
+  module SDK
+    module Provider
+      # Defines the default provider that is set if no provider is specified.
+      #
+      # To use <tt>NoOpProvider</tt>, it can be set during the configuration of the SDK
+      #
+      #   OpenFeature::SDK.configure do |config|
+      #     config.provider = NoOpProvider.new
+      #   end
+      #
+      # Within the <tt>NoOpProvider</tt>, the following methods exist
+      #
+      # * <tt>fetch_boolean_value</tt> - Retrieve feature flag boolean value
+      #
+      # * <tt>fetch_string_value</tt> - Retrieve feature flag string value
+      #
+      # * <tt>fetch_number_value</tt> - Retrieve feature flag number value
+      #
+      # * <tt>fetch_object_value</tt> - Retrieve feature flag object value
+      #
+      class NoOpProvider
+        REASON_NO_OP = "No-op"
+        NAME = "No-op Provider"
+
+        attr_reader :metadata
+
+        def initialize
+          @metadata = Metadata.new(name: NAME).freeze
+        end
+
+        def fetch_boolean_value(flag_key:, default_value:, evaluation_context: nil)
+          no_op(default_value)
+        end
+
+        def fetch_string_value(flag_key:, default_value:, evaluation_context: nil)
+          no_op(default_value)
+        end
+
+        def fetch_number_value(flag_key:, default_value:, evaluation_context: nil)
+          no_op(default_value)
+        end
+
+        def fetch_object_value(flag_key:, default_value:, evaluation_context: nil)
+          no_op(default_value)
+        end
+
+        private
+
+        def no_op(default_value)
+          Struct.new("ResolutionDetails", :value, :reason)
+        end
+      end
+    end
+  end
+end
+# rubocop:enable Lint/UnusedMethodArgument