Ts/global lock awareness

app/models/shipit/lock_providers/config.rb

@@ -0,0 +1,27 @@
+# frozen_string_literal: true
+
+module Shipit
+  module LockProviders
+    class Config
+      class MissingConfigError < StandardError; end
+      attr_accessor :provider
+
+      class << self
+        delegate :provider, to: :config
+
+        def configure
+          yield config
+          config
+        end
+
+        def config
+          @config ||= new(provider: NullProvider.new)
+        end
+      end
+
+      def initialize(provider:)
+        @provider = provider
+      end
+    end
+  end
+end

app/models/shipit/lock_providers/null_provider.rb

@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+module Shipit
+  module LockProviders
+    class NullProvider < Provider
+      def try_lock
+        nil
+      end
+    end
+  end
+end

app/models/shipit/lock_providers/provider.rb

@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+module Shipit
+  module LockProviders
+    class Provider
+      def try_lock
+        raise NotImplementedError, "you must implement #try_lock"
+      end
+    end
+  end
+end

app/models/shipit/stack.rb

@@ -469,6 +469,8 @@ def occupied
     end
 
     def locked?
+      LockProviders::Config.provider.try_lock
+
       lock_reason.present?
     end
 

test/models/shipit/lock_providers/config_test.rb

@@ -0,0 +1,31 @@
+# frozen_string_literal: true
+
+require 'test_helper'
+
+module Shipit
+  module LockProviders
+    class ConfigTest < ActiveSupport::TestCase
+      class TestProvider < Provider
+        def try_lock
+          nil
+        end
+      end
+
+      def setup
+        @original_config = Config.config
+        Config.instance_variable_set(:@config, nil)
+      end
+
+      def teardown
+        Config.instance_variable_set(:@config, @original_config)
+      end
+
+      test "configure creates a new config instance with default provider" do
+        config = Config.configure do |c|
+          c.provider = TestProvider
+        end
+        assert_equal TestProvider, config.provider
+      end
+    end
+  end
+end

test/models/shipit/lock_providers/null_provider_test.rb

@@ -0,0 +1,13 @@
+# frozen_string_literal: true
+
+require 'test_helper'
+
+module Shipit
+  module LockProviders
+    class NullProviderTest < ActiveSupport::TestCase
+      test "try_lock returns nil" do
+        assert_nil NullProvider.new.try_lock
+      end
+    end
+  end
+end

test/models/shipit/lock_providers/provider_test.rb

@@ -0,0 +1,22 @@
+# frozen_string_literal: true
+
+require 'test_helper'
+
+module Shipit
+  module LockProviders
+    class ProviderTest < ActiveSupport::TestCase
+      test "try_lock raises NotImplementedError" do
+        provider = Provider.new
+        assert_raises(NotImplementedError, "you must implement #try_lock") do
+          provider.try_lock
+        end
+      end
+
+      test "BaseProvider is abstract and cannot be instantiated directly" do
+        assert_raises(NotImplementedError) do
+          Provider.new.try_lock
+        end
+      end
+    end
+  end
+end

test/models/shipit/stack_test.rb

@@ -749,6 +749,25 @@ def self.deliver(event, stack, payload)
       assert_equal expected, @stack.locked_since
     end
 
+    test "#locked? updates lock if LockProvider finds lock" do
+      class LockedProvider < LockProviders::Provider
+        def initialize(stack)
+          @stack = stack
+        end
+
+        def try_lock
+          @stack.lock("test lock", AnonymousUser.new)
+        end
+      end
+
+      refute @stack.locked?
+      LockProviders::Config.configure { |c| c.provider = LockedProvider.new(@stack) }
+      assert @stack.locked?
+      assert_equal "test lock", @stack.lock_reason
+    ensure
+      LockProviders::Config.configure { |c| c.provider = LockProvides::NullProvider.new }
+    end
+
     test "#lock sets reason and user" do
       reason = "Here comes the walrus"
       user = shipit_users(:walrus)