Use INotify to wait for ansible-runner pid file

Gemfile

@@ -68,6 +68,7 @@ gem "query_relation",                 "~>0.1.0",       :require => false
 gem "rails",                          "~>5.2.4", ">=5.2.4.4"
 gem "rails-i18n",                     "~>5.x"
 gem "rake",                           ">=12.3.3",      :require => false
+gem "rb-inotify",                     "~>0.10.0",      :require => false
 gem "rest-client",                    "~>2.1.0",       :require => false
 gem "ripper_ruby_parser",             "~>1.5.1",       :require => false
 gem "ruby-progressbar",               "~>1.7.0",       :require => false

lib/ansible/runner.rb

@@ -216,7 +216,11 @@ def run_via_cli(hosts, credentials, env_vars, extra_vars, tags: nil, ansible_run
 
         begin
           fetch_galaxy_roles(playbook_or_role_args)
-          result = AwesomeSpawn.run("ansible-runner", :env => env_vars_hash, :params => params)
+
+          result = wait_for(pid_file(base_dir)) do
+            AwesomeSpawn.run("ansible-runner", :env => env_vars_hash, :params => params)
+          end
+
           res = response(base_dir, ansible_runner_method, result)
         ensure
           # Clean up the tmp dir for the sync method, for async we will clean it up after the job is finished and we've
@@ -354,6 +358,37 @@ def env_dir(base_dir)
         FileUtils.mkdir_p(File.join(base_dir, "env")).first
       end
 
+      def pid_file(base_dir)
+        File.join(base_dir, "pid")
+      end
+
+      def wait_for(path)
+        require "rb-inotify"
+        dir_name  = File.dirname(path)
+        file_name = File.basename(path)
+
+        path_created = Concurrent::Event.new
+
+        notifier = INotify::Notifier.new
+        notifier.watch(dir_name, :moved_to, :create) do |event|
+          # Once the file we are looking for is created set the concurrent event
+          path_created.set if event.name == file_name
+        end
+
+        thread = Thread.new { notifier.run }
+
+        res = yield
+
+        # Wait for the target file to exist
+        path_created.wait
+
+        # Shutdown the inotify loop and join the thread
+        notifier.close
+        thread.join
+
+        res
+      end
+
       PYTHON2_MODULE_PATHS = %w[
         /var/lib/manageiq/venv/lib/python2.7/site-packages
       ].freeze