diff options
| -rw-r--r-- | cloudinit/gpg.py | 52 | ||||
| -rw-r--r-- | cloudinit/tests/test_gpg.py | 54 |
2 files changed, 96 insertions, 10 deletions
diff --git a/cloudinit/gpg.py b/cloudinit/gpg.py index d58d73e0..7fe17a2e 100644 --- a/cloudinit/gpg.py +++ b/cloudinit/gpg.py @@ -10,6 +10,8 @@ from cloudinit import log as logging from cloudinit import util +import time + LOG = logging.getLogger(__name__) @@ -25,16 +27,46 @@ def export_armour(key): return armour -def recv_key(key, keyserver): - """Receive gpg key from the specified keyserver""" - LOG.debug('Receive gpg key "%s"', key) - try: - util.subp(["gpg", "--keyserver", keyserver, "--recv", key], - capture=True) - except util.ProcessExecutionError as error: - raise ValueError(('Failed to import key "%s" ' - 'from server "%s" - error %s') % - (key, keyserver, error)) +def recv_key(key, keyserver, retries=(1, 1)): + """Receive gpg key from the specified keyserver. + + Retries are done by default because keyservers can be unreliable. + Additionally, there is no way to determine the difference between + a non-existant key and a failure. In both cases gpg (at least 2.2.4) + exits with status 2 and stderr: "keyserver receive failed: No data" + It is assumed that a key provided to cloud-init exists on the keyserver + so re-trying makes better sense than failing. + + @param key: a string key fingerprint (as passed to gpg --recv-keys). + @param keyserver: the keyserver to request keys from. + @param retries: an iterable of sleep lengths for retries. + Use None to indicate no retries.""" + LOG.debug("Importing key '%s' from keyserver '%s'", key, keyserver) + cmd = ["gpg", "--keyserver=%s" % keyserver, "--recv-keys", key] + if retries is None: + retries = [] + trynum = 0 + error = None + sleeps = iter(retries) + while True: + trynum += 1 + try: + util.subp(cmd, capture=True) + LOG.debug("Imported key '%s' from keyserver '%s' on try %d", + key, keyserver, trynum) + return + except util.ProcessExecutionError as e: + error = e + try: + naplen = next(sleeps) + LOG.debug( + "Import failed with exit code %d, will try again in %ss", + error.exit_code, naplen) + time.sleep(naplen) + except StopIteration: + raise ValueError( + ("Failed to import key '%s' from keyserver '%s' " + "after %d tries: %s") % (key, keyserver, trynum, error)) def delete_key(key): diff --git a/cloudinit/tests/test_gpg.py b/cloudinit/tests/test_gpg.py new file mode 100644 index 00000000..0562b966 --- /dev/null +++ b/cloudinit/tests/test_gpg.py @@ -0,0 +1,54 @@ +# This file is part of cloud-init. See LICENSE file for license information. +"""Test gpg module.""" + +from cloudinit import gpg +from cloudinit import util +from cloudinit.tests.helpers import CiTestCase + +import mock + + +@mock.patch("cloudinit.gpg.time.sleep") +@mock.patch("cloudinit.gpg.util.subp") +class TestReceiveKeys(CiTestCase): + """Test the recv_key method.""" + + def test_retries_on_subp_exc(self, m_subp, m_sleep): + """retry should be done on gpg receive keys failure.""" + retries = (1, 2, 4) + my_exc = util.ProcessExecutionError( + stdout='', stderr='', exit_code=2, cmd=['mycmd']) + m_subp.side_effect = (my_exc, my_exc, ('', '')) + gpg.recv_key("ABCD", "keyserver.example.com", retries=retries) + self.assertEqual([mock.call(1), mock.call(2)], m_sleep.call_args_list) + + def test_raises_error_after_retries(self, m_subp, m_sleep): + """If the final run fails, error should be raised.""" + naplen = 1 + keyid, keyserver = ("ABCD", "keyserver.example.com") + m_subp.side_effect = util.ProcessExecutionError( + stdout='', stderr='', exit_code=2, cmd=['mycmd']) + with self.assertRaises(ValueError) as rcm: + gpg.recv_key(keyid, keyserver, retries=(naplen,)) + self.assertIn(keyid, str(rcm.exception)) + self.assertIn(keyserver, str(rcm.exception)) + m_sleep.assert_called_with(naplen) + + def test_no_retries_on_none(self, m_subp, m_sleep): + """retry should not be done if retries is None.""" + m_subp.side_effect = util.ProcessExecutionError( + stdout='', stderr='', exit_code=2, cmd=['mycmd']) + with self.assertRaises(ValueError): + gpg.recv_key("ABCD", "keyserver.example.com", retries=None) + m_sleep.assert_not_called() + + def test_expected_gpg_command(self, m_subp, m_sleep): + """Verify gpg is called with expected args.""" + key, keyserver = ("DEADBEEF", "keyserver.example.com") + retries = (1, 2, 4) + m_subp.return_value = ('', '') + gpg.recv_key(key, keyserver, retries=retries) + m_subp.assert_called_once_with( + ['gpg', '--keyserver=%s' % keyserver, '--recv-keys', key], + capture=True) + m_sleep.assert_not_called() |