title: Supervisord using environment variables in command
body: <p>My supervisor configuration file</p>
  
  <pre><code>environment=USER=%(ENV_FLOWER_USER_NAME),PASS=%(ENV_FLOWER_PASSWORD)
  command=/usr/local/opt/python/bin/flower --basic_auth=%(ENV_USER}:%(ENV_PASS)
  </code></pre>
  
  <p>When I start supervisord, I receive the following error</p>
  
  <blockquote>
    <p>Restarting supervisor: Error: Format string
    'USER=%(ENV_FLOWER_USER_NAME),PASS=%(ENV_FLOWER_PASSWORD)' for
    'environment' is badly formatted</p>
  </blockquote>
  
  <p>Any ideas?</p>