Merge remote-tracking branch 'remotes/origin/master' into rmq_removal

1 files changed, 22 insertions, 6 deletions

diff --git a/snekbox.py b/snekbox.py
index 4e3e4fa..5946e12 100644
--- a/snekbox.py
+++ b/snekbox.py
@@ -1,33 +1,49 @@
-import subprocess
 import os
+import subprocess
 import sys
 
 from flask import Flask, render_template, request, jsonify
 
 
-class Snekbox(object):
+class Snekbox:
+    """Core snekbox functionality, providing safe execution of Python code."""
+
     def __init__(self,
                  nsjail_binary='nsjail',
-                 python_binary=os.path.dirname(sys.executable)+os.sep+'python3.6'):
+                 python_binary=os.path.dirname(sys.executable) + os.sep + 'python3.6'):
         self.nsjail_binary = nsjail_binary
         self.python_binary = python_binary
-        self.nsjail_workaround()
+        self._nsjail_workaround()
 
     env = {
-        'PATH': '/snekbox/.venv/bin:/usr/local/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin',
+        'PATH': (
+            '/snekbox/.venv/bin:/usr/local/bin:/usr/local/'
+            'sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin'
+        ),
         'LANG': 'en_US.UTF-8',
         'PYTHON_VERSION': '3.6.5',
         'PYTHON_PIP_VERSION': '10.0.1',
         'PYTHONDONTWRITEBYTECODE': '1',
     }
 
-    def nsjail_workaround(self):
+    def _nsjail_workaround(self):
         dirs = ['/sys/fs/cgroup/pids/NSJAIL', '/sys/fs/cgroup/memory/NSJAIL']
         for d in dirs:
             if not os.path.exists(d):
                 os.makedirs(d)
 
     def python3(self, cmd):
+        """
+        Execute Python 3 code in a isolated environment.
+
+        The value of ``cmd`` is passed using '-c' to a Python
+        interpreter that is started in a ``nsjail``, isolating it
+        from the rest of the system.
+
+        Returns the output of executing the command (stdout) if
+        successful, or a error message if the execution failed.
+        """
+
         args = [self.nsjail_binary, '-Mo',
                 '--rlimit_as', '700',
                 '--chroot', '/',