Merge pull request #495 from edx/dcs/config-perm

Check for file permissions

edx_proctoring/apps.py

@@ -40,10 +40,15 @@ def make_worker_config(backends, out='/tmp/workers.json'):
         except KeyError:
             warnings.warn('%r does not contain a `main` entry' % package_file)
     if config:
-        with open(out, 'wb') as outfp:
-            json.dump(config, outfp)
-        os.chmod(out, 0o664)
-        return True
+        try:
+            with open(out, 'wb+') as outfp:
+                json.dump(config, outfp)
+        except IOError:
+            warnings.warn("Could not write worker config to %s" % out)
+        else:
+            # make sure that this file is group writable, because it may be written by different users
+            os.chmod(out, 0o664)
+            return True
     return False
 
 

edx_proctoring/tests/test_workerconfig.py

@@ -80,6 +80,13 @@ def test_no_module(self):
         self.assertFalse(make_worker_config([backend], self.outfile))
         self._check_outfile(None)
 
+    def test_no_permission(self):
+        self.outfile = '/etc/workers-test.json'
+        backend = TestBackendProvider()
+        backend.npm_module = self._make_npm_module('test-1234', 'foo/bar/baz.js')
+        self.assertFalse(make_worker_config([backend], self.outfile))
+        self._check_outfile(None)
+
     @patch('django.conf.settings.NODE_MODULES_ROOT', None)
     def test_no_setting(self):
         backend = TestBackendProvider()