Catch exceptions when parsing config file

cli/tests/data/config/parse_error.toml

@@ -0,0 +1,2 @@
+header]
+key=value

cli/tests/integrations/test_config.py

@@ -440,6 +440,19 @@ def test_timeout(missing_env):
     _unset_value('marathon.url', None, missing_env)
 
 
+def test_parse_error():
+    env = os.environ.copy()
+    path = os.path.join('tests', 'data', 'config', 'parse_error.toml')
+    env['DCOS_CONFIG'] = path
+
+    assert_command(['dcos', 'config', 'show'],
+                   returncode=1,
+                   stderr=six.b(("Error parsing config file at [{}]: Found "
+                                 "invalid character in key name: ']'. "
+                                 "Try quoting the key name.\n").format(path)),
+                   env=env)
+
+
 def _fail_url_validation(command, key, value, env):
     returncode_, stdout_, stderr_ = exec_command(
         ['dcos', 'config', command, key, value], env=env)

dcos/config.py

@@ -2,6 +2,7 @@ import collections
 
 import toml
 from dcos import util
+from dcos.errors import DCOSException
 
 
 def load_from_path(path, mutable=False):
@@ -17,7 +18,11 @@ def load_from_path(path, mutable=False):
 
     util.ensure_file_exists(path)
     with util.open_file(path, 'r') as config_file:
-        toml_obj = toml.loads(config_file.read())
+        try:
+            toml_obj = toml.loads(config_file.read())
+        except Exception as e:
+            raise DCOSException(
+                'Error parsing config file at [{}]: {}'.format(path, e))
         return (MutableToml if mutable else Toml)(toml_obj)