title: How to determine what user and group a Python script is running as?
body: <p>I have a CGI script that is getting an <code>"IOError: [Errno 13] Permission denied"</code> error in the stack trace in the web server's error log.</p>
  
  <p>As part of debugging this problem, I'd like to add a little bit of code to the script to print the user and (especially) group that the script is running as, into the error log (presumably STDERR).</p>
  
  <p>I know I can just print the values to <code>sys.stderr</code>, but how do I figure out what user and group the script is running as?</p>
  
  <p>(I'm particularly interested in the group, so the <code>$USER</code> environment variable won't help; the CGI script has the setgid bit set so it should be running as group "list" instead of the web server's "www-data" - but I need code to see if that's actually happening.)</p>