title: Run task from another periodic task with celery
body: <p>I have periodic task which should trigger another task. Final expected behavior: first task should collect some data from external service and then loop over this data (list) and call another task with passing over argument (current iteration in loop). I want to have those tasks in loop being asynchronical.</p>
  <p>I wrote code that runs a task in period, but I can't figure out how this task should call another task, because when I do it by <code>.delay()</code> method then nothing happens.</p>
  <p>Here is some simplified code that I want to run:</p>
  <pre><code>@celery_app.task(name=&quot;Hello World&quot;)
  def hello_world():
      print(f&quot;HELLO WORLD PRINT&quot;)
      add.delay(2, 2)
      return 'Hello'
  
  
  @celery_app.task
  def add(x, y):
      with open(f&quot;./{str(datetime.datetime.now())}.txt&quot;, 'w') as file:
          file.write(str(x+y))
      print(f&quot;x + y = {x + y}&quot;)
      return x + y
  </code></pre>
  <p>For now <code>hello_world()</code> is running every 30 sec and as a result I receive HELLO WORLD PRINT in logs, but add task is not running. I can't see either print or file that should be created by this task.</p>
  <p>Update for comment, here is how I use queue:</p>
  <pre><code>celery_app.conf.task_routes = {
      &quot;project.app.hello_world&quot;: {
          &quot;queue&quot;: 'test_queue'
      },
      &quot;project.app.add&quot;: {
          &quot;queue&quot;: 'test_queue'
      },
  </code></pre>