title: Flask app on Heroku keeps booting workers
body: <p>I have a flask app running on Heroku. Until yesterday everything worked fine.
  Now for some reason today, the web app keeps booting workers:</p>
  
  <pre><code>2017-09-28T07:02:06.869090+00:00 app[web.1]: [2017-09-28 07:02:06 +0000] [3882] [INFO] Booting worker with pid: 3882
  2017-09-28T07:02:07.308558+00:00 app[web.1]: [2017-09-28 07:02:07 +0000] [3899] [INFO] Booting worker with pid: 3899
  2017-09-28T07:02:07.626838+00:00 app[web.1]: [2017-09-28 07:02:07 +0000] [3901] [INFO] Booting worker with pid: 3901
  2017-09-28T07:02:07.906617+00:00 app[web.1]: [2017-09-28 07:02:07 +0000] [3909] [INFO] Booting worker with pid: 3909
  2017-09-28T07:02:08.701473+00:00 app[web.1]: [2017-09-28 07:02:08 +0000] [3926] [INFO] Booting worker with pid: 3926
  2017-09-28T07:02:08.890857+00:00 app[web.1]: [2017-09-28 07:02:08 +0000] [3928] [INFO] Booting worker with pid: 3928
  2017-09-28T07:02:09.543447+00:00 app[web.1]: [2017-09-28 07:02:09 +0000] [3936] [INFO] Booting worker with pid: 3936
  2017-09-28T07:02:10.724376+00:00 app[web.1]: [2017-09-28 07:02:10 +0000] [3946] [INFO] Booting worker with pid: 3946
  2017-09-28T07:02:11.771921+00:00 app[web.1]: [2017-09-28 07:02:11 +0000] [3962] [INFO] Booting worker with pid: 3962
  2017-09-28T07:02:11.830635+00:00 app[web.1]: [2017-09-28 07:02:11 +0000] [3963] [INFO] Booting worker with pid: 3963
  </code></pre>
  
  <p>Of course now the app cannot work normally anymore, any requests sent to it is timed-out.
  Here is the Procfile:</p>
  
  <pre><code>web: gunicorn app:app
  </code></pre>
  
  <p>And the requirement.txt:</p>
  
  <pre><code>scipy
  numpy
  flask
  gunicorn
  pillow
  tensorflow
  </code></pre>
  
  <p>The app works fine when I run it locally with the command:</p>
  
  <pre><code>heroku local web
  </code></pre>
  
  <p>I have submitted a ticket to Heroku, but in case anybody can help here it would save me a lot of time.</p>
  
  <p>Thanks</p>