Sequel adapter

lib/statesman.rb

@@ -5,15 +5,15 @@ module Statesman
   autoload :Guard,      'statesman/guard'
   autoload :Version,    'statesman/version'
   module Adapters
-    autoload :Memory,       "statesman/adapters/memory"
-    autoload :ActiveRecord, "statesman/adapters/active_record"
+    autoload :Memory,               "statesman/adapters/memory"
+    autoload :ActiveRecord,         "statesman/adapters/active_record"
     autoload :ActiveRecordTransition,
              "statesman/adapters/active_record_transition"
-    autoload :ActiveRecordQueries,
-             "statesman/adapters/active_record_queries"
-    autoload :Mongoid,      "statesman/adapters/mongoid"
-    autoload :MongoidTransition,
-             "statesman/adapters/mongoid_transition"
+    autoload :ActiveRecordQueries, "statesman/adapters/active_record_queries"
+    autoload :Sequel,              "statesman/adapters/sequel"
+    autoload :SequelTransistion,   "statesman/adapters/sequel_transition"
+    autoload :Mongoid,             "statesman/adapters/mongoid"
+    autoload :MongoidTransition,   "statesman/adapters/mongoid_transition"
   end
 
   # Example:

lib/statesman/adapters/sequel.rb

@@ -0,0 +1,81 @@
+require_relative "../exceptions"
+
+module Statesman
+  module Adapters
+    class Sequel
+      attr_reader :transition_class, :parent_model, :observer
+
+      ::Sequel.extension(:inflector)
+
+      def initialize(transition_class, parent_model, observer)
+        @transition_class = transition_class
+        @parent_model = parent_model
+        @observer = observer
+      end
+
+      def create(from, to, metadata = {})
+        create_transition(from.to_s, to.to_s, metadata)
+      ensure
+        @last_transition = nil
+      end
+
+      def history
+        history_dataset.all
+      end
+
+      def last
+        @last_transition ||= history_dataset.last
+      end
+
+      private
+
+      def history_dataset
+        transitions_for_parent.order(:sort_key)
+      end
+
+      def transitions_for_parent
+        @parent_model.send("#{transition_table_name}_dataset")
+      end
+
+      def next_sort_key
+        (last && last.sort_key + 10) || 0
+      end
+
+      def create_transition(from, to, metadata)
+        transition = transition_class.new(
+          to_state: to,
+          sort_key: next_sort_key,
+          metadata: metadata,
+          parent_model_foreign_key => @parent_model.pk
+        )
+
+        parent_model_class.db.transaction do
+          @observer.execute(:before, from, to, transition)
+          transition.save
+          @last_transition = transition
+          @observer.execute(:after, from, to, transition)
+        end
+
+        @observer.execute(:after_commit, from, to, transition)
+
+        transition
+      end
+
+      def transition_table_name
+        @transition_table_name ||= @transition_class.table_name
+      end
+
+      def parent_model_class
+        @parent_model_class ||= @parent_model.class
+      end
+
+      def parent_association_name
+        parent_model_class.table_name.to_s.singularize.to_sym
+      end
+
+      def parent_model_foreign_key
+        @transition_class.association_reflection(parent_association_name)[:key]
+      end
+    end
+  end
+end

lib/statesman/adapters/sequel_transition.rb

@@ -0,0 +1,12 @@
+require "json"
+require "sequel"
+
+module Statesman
+  module Adapters
+    module SequelTransition
+      def self.included(base)
+        base.send(:plugin, :serialization, :json, :metadata)
+      end
+    end
+  end
+end

spec/spec_helper.rb

@@ -3,7 +3,8 @@
 require "active_record"
 require "support/active_record"
 require "mongoid"
-require 'rspec/its'
+require "sequel"
+require "rspec/its"
 
 RSpec.configure do |config|
   config.raise_errors_for_deprecations!
@@ -38,6 +39,13 @@
     puts "Running with database adapter '#{db_adapter}'"
   end
 
+  if config.exclusion_filter[:sequel]
+    puts "Skipping Sequel tests"
+  else
+    Sequel::Model.db = Sequel.sqlite
+    require "support/sequel"
+  end
+
   config.before(:each, active_record: true) do
     tables = %w(my_active_record_models my_active_record_model_transitions)
     tables.each do |table_name|
@@ -57,4 +65,12 @@ def prepare_transitions_table
       end
     end
   end
+
+  config.before(:each, sequel: true) do
+    SequelMigrator.new(Sequel::Model.db).up
+  end
+
+  config.after(:each, sequel: true)  do
+    SequelMigrator.new(Sequel::Model.db).down
+  end
 end

spec/statesman/adapters/active_record_spec.rb

@@ -1,5 +1,6 @@
 require "spec_helper"
-require "statesman/adapters/shared_examples"
+require "statesman/adapters/adapter_behaviour"
+require "statesman/adapters/sql_adapter_behaviour"
 require "statesman/exceptions"
 
 describe Statesman::Adapters::ActiveRecord, active_record: true do
@@ -12,6 +13,10 @@
   let(:observer) { double(Statesman::Machine, execute: nil) }
   let(:model) { MyActiveRecordModel.create(current_state: :pending) }
   it_behaves_like "an adapter", described_class, MyActiveRecordModelTransition
+  it_behaves_like "a SQL adapter",
+                  described_class, MyActiveRecordModelTransition do
+    let(:association_name) { :my_active_record_model_transitions }
+  end
 
   describe "#initialize" do
     context "with unserialized metadata and non json column type" do
@@ -109,25 +114,6 @@
       described_class.new(MyActiveRecordModelTransition, model, observer)
     end
 
-    before { adapter.create(:x, :y) }
-
-    context "with a previously looked up transition" do
-      before { adapter.last }
-
-      it "caches the transition" do
-        expect_any_instance_of(MyActiveRecordModel).
-          to receive(:my_active_record_model_transitions).never
-        adapter.last
-      end
-
-      context "and a new transition" do
-        before { adapter.create(:y, :z, []) }
-        it "retrieves the new transition from the database" do
-          expect(adapter.last.to_state).to eq("z")
-        end
-      end
-    end
-
     context "with a pre-fetched transition history" do
       before { adapter.create(:x, :y) }
       before { model.my_active_record_model_transitions.load_target }

spec/statesman/adapters/shared_examples.rb → spec/statesman/adapters/adapter_behaviour.rb

@@ -4,7 +4,6 @@
 #   initialize:       Accepts a transition class, parent model and state_attr.
 #   transition_class: Returns the transition class object passed to initialize.
 #   parent_model:     Returns the model class object passed to initialize.
-#   state_attr:       Returns the state attribute to set on the parent.
 #   create:           Accepts to_state, before callbacks, after callbacks and
 #                     optional metadata. Creates a new transition class
 #                     instance and saves metadata to it.
@@ -29,7 +28,7 @@
     let(:create) { adapter.create(from, to) }
     subject { -> { create } }
 
-    it { is_expected.to change(adapter.history, :count).by(1) }
+    it { is_expected.to change { adapter.history.count }.from(0).to(1) }
 
     context "the new transition" do
       subject { create }

spec/statesman/adapters/memory_spec.rb

@@ -1,5 +1,5 @@
 require "spec_helper"
-require "statesman/adapters/shared_examples"
+require "statesman/adapters/adapter_behaviour"
 require "statesman/adapters/memory_transition"
 
 describe Statesman::Adapters::Memory do

spec/statesman/adapters/mongoid_spec.rb

@@ -1,5 +1,5 @@
 require "spec_helper"
-require "statesman/adapters/shared_examples"
+require "statesman/adapters/adapter_behaviour"
 require "statesman/exceptions"
 require "support/mongoid"
 require "mongoid"

spec/statesman/adapters/sequel_spec.rb

@@ -0,0 +1,18 @@
+require "spec_helper"
+require "statesman/adapters/adapter_behaviour"
+require "statesman/adapters/sql_adapter_behaviour"
+
+describe Statesman::Adapters::Sequel, sequel: true do
+  before do
+    MySequelModel.dataset = MySequelModel.dataset
+    MySequelModelTransition.dataset = MySequelModelTransition.dataset
+  end
+
+  let(:observer) { double(Statesman::Machine, execute: nil) }
+  let(:model) { MySequelModel.create(current_state: :pending) }
+
+  it_behaves_like "an adapter", described_class, MySequelModelTransition
+  it_behaves_like "a SQL adapter", described_class, MySequelModelTransition do
+    let(:association_name) { :my_sequel_model_transitions_dataset }
+  end
+end

spec/statesman/adapters/sql_adapter_behaviour.rb

@@ -0,0 +1,25 @@
+require "spec_helper"
+
+shared_examples_for "a SQL adapter" do |adapter_class, transition_class|
+  describe "#last" do
+    let(:adapter) { adapter_class.new(transition_class, model, observer) }
+
+    before { adapter.create(:x, :y) }
+
+    context "with a previously looked up transition" do
+      before { adapter.last }
+
+      it "caches the transition" do
+        expect_any_instance_of(model.class).to receive(association_name).never
+        adapter.last
+      end
+
+      context "and a new transition" do
+        before { adapter.create(:y, :z, []) }
+        it "retrieves the new transition from the database" do
+          expect(adapter.last.to_state).to eq("z")
+        end
+      end
+    end
+  end
+end

spec/support/sequel.rb

@@ -0,0 +1,29 @@
+require "json"
+require "sequel"
+require_relative "./sequel_migrations"
+require_relative "../../lib/statesman/adapters/sequel_transition"
+
+class SequelStateMachine
+  include Statesman::Machine
+
+  state :initial, initial: true
+  state :succeeded
+  state :failed
+
+  transition from: :initial, to: [:succeeded, :failed]
+  transition from: :failed,  to: :initial
+end
+
+class MySequelModel < Sequel::Model
+  one_to_many :my_sequel_model_transitions
+
+  def state_machine
+    @state_machine ||= SequelStateMachine.new(
+      self, transition_class: MySequelModelTransition)
+  end
+end
+
+class MySequelModelTransition < Sequel::Model
+  include Statesman::Adapters::SequelTransition
+  many_to_one :my_sequel_model
+end

spec/support/sequel_migrations.rb

@@ -0,0 +1,41 @@
+require "sequel"
+
+class SequelMigrator
+  MODEL_TABLE = "my_sequel_models"
+  TRANSITION_TABLE = "my_sequel_model_transitions"
+
+  def initialize(db)
+    @db = db
+  end
+
+  def up
+    down
+    create_model_table
+    create_transition_table
+  end
+
+  def down
+    [TRANSITION_TABLE, MODEL_TABLE].each do |table_name|
+      @db.execute("DROP TABLE IF EXISTS #{table_name};")
+    end
+  end
+
+  private
+
+  def create_model_table
+    @db.create_table(:my_sequel_models) do
+      primary_key :id, type: Bignum
+      String :current_state
+    end
+  end
+
+  def create_transition_table
+    @db.create_table(:my_sequel_model_transitions) do
+      primary_key :id, type: Bignum
+      String :to_state
+      foreign_key :my_sequel_model_id, :my_sequel_models
+      Bignum :sort_key, index: true, unique: true
+      String :metadata
+    end
+  end
+end

statesman.gemspec

@@ -28,6 +28,7 @@ Gem::Specification.new do |spec|
   spec.add_development_dependency "sqlite3",       "~> 1.3"
   spec.add_development_dependency "mongoid",       ">= 3.1"
   spec.add_development_dependency "activerecord",  ">= 3.2"
+  spec.add_development_dependency "sequel",        "~> 4.20.0"
   spec.add_development_dependency "pg",            "~> 0.18"
   spec.add_development_dependency "mysql2",        "~> 0.3"
   spec.add_development_dependency "ammeter",       "~> 1.1"