Do not allow GoodJob to automatically start after Rails initializatio…

…n if previously shutdown (#976)

lib/good_job/capsule.rb

@@ -15,17 +15,18 @@ def initialize(configuration: GoodJob.configuration)
       self.class.instances << self
       @configuration = configuration
 
-      @autostart = true
+      @startable = true
       @running = false
       @mutex = Mutex.new
     end
 
-    # Start executing jobs (if not already running).
-    def start
-      return if @running
+    # Start the capsule once. After a shutdown, {#restart} must be used to start again.
+    # @return [nil, Boolean] Whether the capsule was started.
+    def start(force: false)
+      return unless startable?(force: force)
 
       @mutex.synchronize do
-        return if @running
+        return unless startable?(force: force)
 
         @notifier = GoodJob::Notifier.new(enable_listening: @configuration.enable_listen_notify)
         @poller = GoodJob::Poller.new(poll_interval: @configuration.poll_interval)
@@ -35,7 +36,7 @@ def start
 
         @cron_manager = GoodJob::CronManager.new(@configuration.cron_entries, start_on_initialize: true) if @configuration.enable_cron?
 
-        @autostart = false
+        @startable = false
         @running = true
       end
     end
@@ -50,7 +51,7 @@ def start
     def shutdown(timeout: :default)
       timeout = timeout == :default ? @configuration.shutdown_timeout : timeout
       GoodJob._shutdown_all([@notifier, @poller, @scheduler, @cron_manager].compact, timeout: timeout)
-      @autostart = false
+      @startable = false
       @running = false
     end
 
@@ -61,7 +62,7 @@ def restart(timeout: :default)
       raise ArgumentError, "Capsule#restart cannot be called with a timeout of nil" if timeout.nil?
 
       shutdown(timeout: timeout)
-      start
+      start(force: true)
     end
 
     # @return [Boolean] Whether the capsule is currently running.
@@ -76,10 +77,16 @@ def shutdown?
 
     # Creates an execution thread(s) with the given attributes.
     # @param job_state [Hash, nil] See {GoodJob::Scheduler#create_thread}.
-    # @return [Boolean, nil] Whether work was started.
+    # @return [Boolean, nil] Whether the thread was created.
     def create_thread(job_state = nil)
-      start if !running? && @autostart
+      start if startable?
       @scheduler&.create_thread(job_state)
     end
+
+    private
+
+    def startable?(force: false)
+      !@running && (@startable || force)
+    end
   end
 end

spec/lib/good_job/capsule_spec.rb

@@ -26,9 +26,35 @@
       capsule.shutdown
       expect(GoodJob::Scheduler.instances.size).to eq 1
     end
+
+    it 'will not start if previously shutdown' do
+      capsule = described_class.new
+      capsule.shutdown
+
+      expect { capsule.start }.not_to change(capsule, :running?).from(false)
+    end
+  end
+
+  describe '#restart' do
+    it 'can start a previously shutdown capsule' do
+      capsule = described_class.new
+      capsule.shutdown
+
+      expect { capsule.restart }.to change(capsule, :running?).from(false).to(true)
+      expect { capsule.restart }.not_to change(capsule, :running?).from(true)
+      expect { capsule.shutdown }.to change(capsule, :running?).from(true).to(false)
+    end
   end
 
   describe '#shutdown' do
+    it 'shuts down the capsule' do
+      capsule = described_class.new
+      capsule.start
+
+      expect { capsule.shutdown }.to change(capsule, :running?).from(true).to(false)
+      expect(GoodJob::Notifier.instances).to all be_shutdown
+    end
+
     it 'operates if the capsule has not been started' do
       capsule = described_class.new
       expect { capsule.shutdown }.not_to raise_error