Add util.check_call

certbot-postfix/certbot_postfix/util.py

@@ -7,6 +7,24 @@ import subprocess
 logger = logging.getLogger(__name__)
 
 
+def check_call(*args, **kwargs):
+    """A simple wrapper of subprocess.check_call that logs errors.
+
+    :param tuple args: positional arguments to subprocess.check_call
+    :param dict kargs: keyword arguments to subprocess.check_call
+
+    :raises subprocess.CalledProcessError: if the call fails
+
+    """
+    try:
+        subprocess.check_call(*args, **kwargs)
+    except subprocess.CalledProcessError:
+        cmd = _get_cmd(*args, **kwargs)
+        logger.debug("%s exited with a non-zero status.",
+                     "".join(cmd), exc_info=True)
+        raise
+
+
 def check_output(*args, **kwargs):
     """Backported version of subprocess.check_output for Python 2.6+.
 
@@ -43,10 +61,19 @@ def check_output(*args, **kwargs):
     output, unused_err = process.communicate()
     retcode = process.poll()
     if retcode:
-        cmd = kwargs.get('args')
-        if cmd is None:
-            cmd = args[0]
+        cmd = _get_cmd(*args, **kwargs)
         logger.debug(
             "'%s' exited with %d. Output was:\n%s", cmd, retcode, output)
         raise subprocess.CalledProcessError(retcode, cmd)
     return output
+
+
+def _get_cmd(*args, **kwargs):
+    """Return the command from Popen args.
+
+    :param tuple args: Popen args
+    :param dict kwargs: Popen kwargs
+
+    """
+    cmd = kwargs.get('args')
+    return args[0] if cmd is None else cmd

certbot-postfix/certbot_postfix/util_test.py

@@ -5,6 +5,29 @@ import unittest
 
 import mock
 
+class CheckCallTest(unittest.TestCase):
+    """Tests for certbot_postfix.util.check_call."""
+
+    @classmethod
+    def _call(cls, *args, **kwargs):
+        from certbot_postfix.util import check_call
+        return check_call(*args, **kwargs)
+
+    @mock.patch('certbot_postfix.util.logger')
+    @mock.patch('certbot_postfix.util.subprocess.check_call')
+    def test_failure(self, mock_check_call, mock_logger):
+        cmd = "postconf smtpd_use_tls=yes".split()
+        mock_check_call.side_effect = subprocess.CalledProcessError(42, cmd)
+        self.assertRaises(subprocess.CalledProcessError, self._call, cmd)
+        self.assertTrue(mock_logger.method_calls)
+
+    @mock.patch('certbot_postfix.util.subprocess.check_call')
+    def test_success(self, mock_check_call):
+        cmd = "postconf smtpd_use_tls=yes".split()
+        self._call(cmd)
+        mock_check_call.assert_called_once_with(cmd)
+
+
 class CheckOutputTest(unittest.TestCase):
     """Tests for certbot_postfix.util.check_output."""