Use a Concurrent::Event for CLI signal-trapping loop (#1141)

lib/good_job/cli.rb

@@ -17,6 +17,9 @@ class CLI < Thor
     # Requiring this loads the application's configuration and classes.
     RAILS_ENVIRONMENT_RB = File.expand_path("config/environment.rb")
 
+    # Number of seconds between checking shutdown conditions
+    SHUTDOWN_EVENT_TIMEOUT = 10
+
     class << self
       # Whether the CLI is running from the executable
       # @return [Boolean, nil]
@@ -106,14 +109,15 @@ def start
         probe_server.start
       end
 
-      @stop_good_job_executable = false
+      require 'concurrent/atomic/event'
+      @stop_good_job_executable = Concurrent::Event.new
       %w[INT TERM].each do |signal|
-        trap(signal) { @stop_good_job_executable = true }
+        trap(signal) { Thread.new { @stop_good_job_executable.set }.join }
       end
 
       Kernel.loop do
-        sleep 0.1
-        break if @stop_good_job_executable || capsule.shutdown?
+        @stop_good_job_executable.wait(SHUTDOWN_EVENT_TIMEOUT)
+        break if @stop_good_job_executable.set? || capsule.shutdown?
       end
 
       systemd.stop do

spec/lib/good_job/cli_spec.rb

@@ -7,6 +7,7 @@
 
   before do
     stub_const 'GoodJob::CLI::RAILS_ENVIRONMENT_RB', File.expand_path("demo/config/environment.rb")
+    stub_const 'GoodJob::CLI::SHUTDOWN_EVENT_TIMEOUT', 0.1
     allow(GoodJob).to receive_messages(configuration: GoodJob::Configuration.new({}), capsule: capsule_mock)
   end
 
@@ -25,7 +26,7 @@
       cli = described_class.new([], {}, {})
 
       cli_thread = Concurrent::Promises.future { cli.start }
-      sleep_until { cli.instance_variable_get(:@stop_good_job_executable) == false }
+      sleep_until { cli.instance_variable_get(:@stop_good_job_executable) }
 
       Process.kill 'INT', Process.pid # Send the signal to ourselves
 
@@ -76,7 +77,7 @@
         cli = described_class.new([], {}, {})
 
         cli_thread = Concurrent::Promises.future { cli.start }
-        sleep_until { cli.instance_variable_get(:@stop_good_job_executable) == false }
+        sleep_until { cli.instance_variable_get(:@stop_good_job_executable) }
         expect(GoodJob::SystemdService).to have_received(:new)
         expect(systemd).to have_received(:start)
         expect(systemd).not_to have_received(:stop)