x/deb-python-tempest-lib
Code Issues Proposed changes

Provide alternative ssh exec_command for non-linux environments

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When running tests that use remote validation on OSX (or any
non-Linux OS), the exec_command method would raise an exception
due to the "poll" method not existing for select. While this
implementation is very safe and reliable, paramiko does provide
other means for handling reading the output from commands. This
patch provide a basic alternative to the existing method that is
only used when the poll method is not available.

Change-Id: Ic14b2331fd59a6311ebe51f598d2cc2320c4389e
Closes-Bug: #1480983
This commit is contained in:
Daryl Walleck
2015-08-13 13:24:42 -05:00
parent ae0294be44
commit 736de8113d
2 changed files with 88 additions and 31 deletions
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28
tempest_lib/common/ssh.py
View File

@@ -96,6 +96,10 @@ class Client(object):
def _is_timed_out(self, start_time):
return (time.time() - self.timeout) > start_time
@staticmethod
def _can_system_poll():
return hasattr(select, 'poll')
def exec_command(self, cmd):
"""Execute the specified command on the server
@@ -114,8 +118,12 @@ class Client(object):
channel.fileno() # Register event pipe
channel.exec_command(cmd)
channel.shutdown_write()
out_data = []
err_data = []
exit_status = channel.recv_exit_status()
# If the executing host is linux-based, poll the channel
if self._can_system_poll():
out_data_chunks = []
err_data_chunks = []
poll = select.poll()
poll.register(channel, select.POLLIN)
start_time = time.time()
@@ -133,18 +141,26 @@ class Client(object):
out_chunk = err_chunk = None
if channel.recv_ready():
out_chunk = channel.recv(self.buf_size)
out_data += out_chunk,
out_data_chunks += out_chunk,
if channel.recv_stderr_ready():
err_chunk = channel.recv_stderr(self.buf_size)
err_data += err_chunk,
err_data_chunks += err_chunk,
if channel.closed and not err_chunk and not out_chunk:
break
exit_status = channel.recv_exit_status()
out_data = ''.join(out_data_chunks)
err_data = ''.join(err_data_chunks)
# Just read from the channels
else:
out_file = channel.makefile('rb', self.buf_size)
err_file = channel.makefile_stderr('rb', self.buf_size)
out_data = out_file.read()
err_data = err_file.read()
if 0 != exit_status:
raise exceptions.SSHExecCommandFailed(
command=cmd, exit_status=exit_status,
stderr=err_data, stdout=out_data)
return ''.join(out_data)
return out_data
def test_connection_auth(self):
"""Raises an exception when we can not connect to server via ssh."""

51
tempest_lib/tests/test_ssh.py
View File

@@ -12,6 +12,7 @@
# License for the specific language governing permissions and limitations
# under the License.
from io import StringIO
import socket
import time
@@ -25,6 +26,8 @@ from tempest_lib.tests import base
class TestSshClient(base.TestCase):
SELECT_POLLIN = 1
@mock.patch('paramiko.RSAKey.from_private_key')
@mock.patch('six.StringIO')
def test_pkey_calls_paramiko_RSAKey(self, cs_mock, rsa_mock):
@@ -109,12 +112,16 @@ class TestSshClient(base.TestCase):
self.assertLess((end_time - start_time), 5)
self.assertGreaterEqual((end_time - start_time), 2)
@mock.patch('select.POLLIN', SELECT_POLLIN, create=True)
def test_exec_command(self):
gsc_mock = self.patch('tempest_lib.common.ssh.Client.'
'_get_ssh_connection')
ito_mock = self.patch('tempest_lib.common.ssh.Client._is_timed_out')
select_mock = self.patch('select.poll')
csp_mock = self.patch(
'tempest_lib.common.ssh.Client._can_system_poll')
csp_mock.return_value = True
select_mock = self.patch('select.poll', create=True)
client_mock = mock.MagicMock()
tran_mock = mock.MagicMock()
chan_mock = mock.MagicMock()
@@ -147,8 +154,8 @@ class TestSshClient(base.TestCase):
chan_mock.exec_command.assert_called_once_with("test")
chan_mock.shutdown_write.assert_called_once_with()
SELECT_POLLIN = 1
poll_mock.register.assert_called_once_with(chan_mock, SELECT_POLLIN)
poll_mock.register.assert_called_once_with(
chan_mock, self.SELECT_POLLIN)
poll_mock.poll.assert_called_once_with(10)
# Test for proper reading of STDOUT and STDERROR and closing
@@ -177,8 +184,9 @@ class TestSshClient(base.TestCase):
chan_mock.exec_command.assert_called_once_with("test")
chan_mock.shutdown_write.assert_called_once_with()
SELECT_POLLIN = 1
poll_mock.register.assert_called_once_with(chan_mock, SELECT_POLLIN)
select_mock.assert_called_once_with()
poll_mock.register.assert_called_once_with(
chan_mock, self.SELECT_POLLIN)
poll_mock.poll.assert_called_once_with(10)
chan_mock.recv_ready.assert_called_once_with()
chan_mock.recv.assert_called_once_with(1024)
@@ -186,3 +194,36 @@ class TestSshClient(base.TestCase):
chan_mock.recv_stderr.assert_called_once_with(1024)
chan_mock.recv_exit_status.assert_called_once_with()
closed_prop.assert_called_once_with()
def test_exec_command_no_select(self):
gsc_mock = self.patch('tempest_lib.common.ssh.Client.'
'_get_ssh_connection')
csp_mock = self.patch(
'tempest_lib.common.ssh.Client._can_system_poll')
csp_mock.return_value = False
select_mock = self.patch('select.poll', create=True)
client_mock = mock.MagicMock()
tran_mock = mock.MagicMock()
chan_mock = mock.MagicMock()
# Test for proper reading of STDOUT and STDERROR
gsc_mock.return_value = client_mock
client_mock.get_transport.return_value = tran_mock
tran_mock.open_session.return_value = chan_mock
chan_mock.recv_exit_status.return_value = 0
std_out_mock = mock.MagicMock(StringIO)
std_err_mock = mock.MagicMock(StringIO)
chan_mock.makefile.return_value = std_out_mock
chan_mock.makefile_stderr.return_value = std_err_mock
client = ssh.Client('localhost', 'root', timeout=2)
client.exec_command("test")
chan_mock.makefile.assert_called_once_with('rb', 1024)
chan_mock.makefile_stderr.assert_called_once_with('rb', 1024)
std_out_mock.read.assert_called_once_with()
std_err_mock.read.assert_called_once_with()
self.assertFalse(select_mock.called)