title: Error when creating log file in uwsgi ini file using date
body: <p>I am trying to deploy my Flask app on Nginx using uWSGI.
  I used <a href="https://www.digitalocean.com/community/tutorials/how-to-serve-flask-applications-with-uwsgi-and-nginx-on-ubuntu-16-04" rel="nofollow noreferrer">this</a> tutorial to deploy my flask app.
  I have the following ini file:
  extractor.ini</p>
  
  <pre><code>    [uwsgi]
      module = wsgi:app
  
      master = true 
      processes = 5
  
      socket = extractor.sock
      chmod-socket = 660
  
      vacuum = true
  
      log-date = @(exec://date +%%F-%%H-%%M)
      logdir = /home/rkok/extractor/logs/
      daemonize = %(logdir)uwsgi-%(log-date).log
  
      die-on-term = true
  </code></pre>
  
  <p>However when I try to start my project using </p>
  
  <pre><code>sudo systemctl start extractor
  </code></pre>
  
  <p>it shows the following error when I check the service status:</p>
  
  <pre><code>uwsgi[31788]: /bin/sh: 1: date: not found
  </code></pre>
  
  <p>I have read <a href="https://stackoverflow.com/a/28344067">here</a> that all 2.x versions should support @(exec://date +%%F-%%H-%%M).
  %%F-%%H-%%M should become YYYY-mm-dd-HH-MM format in the ini file.</p>
  
  <p>I the reactions it says that it could be my path, but I am unsure about how to check my path inside an ini file, as I am using a virtualenv instead of my system environment.
  My system setting:</p>
  
  <pre><code>Ubuntu 16.04 LTS x64
  Python 3.5.2
  Virtualenv 15.1.0
  uWSGI 2.0.15
  Nginx 1.10.3
  </code></pre>
  
  <p>So my question is: How can I get uWSGI to generate a new log file using the system datetime inside the ini file?</p>
  
  <p>ps. My flask app deploys succesfully when I leave out the @(exec://date +%%F-%%H-%%M) part.</p>