SSH: Do not rely on the .closed attribute
This patch is updating the logic in the SSH module to not rely on the
"closed" attribute of the channel object when polling the data. The
"closed" attribute may not set to True as part of the exec_command()
execution stack and in that case would cause the exec_command() (from
the tempest SSH module) to hang.
This patch also uses the context manager when creating the channel so
it gets properly closed at the end of the execution scope.
Closes-Bug: #1571492
Change-Id: I5169faf25c36cfb494c9c1fafb14fb4f7f82cd9e
diff --git a/tempest/lib/common/ssh.py b/tempest/lib/common/ssh.py
index 511dd08..a831dbd 100644
--- a/tempest/lib/common/ssh.py
+++ b/tempest/lib/common/ssh.py
@@ -117,56 +117,56 @@
"""
ssh = self._get_ssh_connection()
transport = ssh.get_transport()
- channel = transport.open_session()
- channel.fileno() # Register event pipe
- channel.exec_command(cmd)
- channel.shutdown_write()
- exit_status = channel.recv_exit_status()
+ with transport.open_session() as channel:
+ channel.fileno() # Register event pipe
+ channel.exec_command(cmd)
+ channel.shutdown_write()
+ 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()
+ # 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()
- while True:
- ready = poll.poll(self.channel_timeout)
- if not any(ready):
- if not self._is_timed_out(start_time):
+ while True:
+ ready = poll.poll(self.channel_timeout)
+ if not any(ready):
+ if not self._is_timed_out(start_time):
+ continue
+ raise exceptions.TimeoutException(
+ "Command: '{0}' executed on host '{1}'.".format(
+ cmd, self.host))
+ if not ready[0]: # If there is nothing to read.
continue
- raise exceptions.TimeoutException(
- "Command: '{0}' executed on host '{1}'.".format(
- cmd, self.host))
- if not ready[0]: # If there is nothing to read.
- continue
- out_chunk = err_chunk = None
- if channel.recv_ready():
- out_chunk = channel.recv(self.buf_size)
- out_data_chunks += out_chunk,
- if channel.recv_stderr_ready():
- err_chunk = channel.recv_stderr(self.buf_size)
- err_data_chunks += err_chunk,
- if channel.closed and not err_chunk and not out_chunk:
- break
- out_data = b''.join(out_data_chunks)
- err_data = b''.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 encoding:
- out_data = out_data.decode(encoding)
- err_data = err_data.decode(encoding)
+ out_chunk = err_chunk = None
+ if channel.recv_ready():
+ out_chunk = channel.recv(self.buf_size)
+ out_data_chunks += out_chunk,
+ if channel.recv_stderr_ready():
+ err_chunk = channel.recv_stderr(self.buf_size)
+ err_data_chunks += err_chunk,
+ if not err_chunk and not out_chunk:
+ break
+ out_data = b''.join(out_data_chunks)
+ err_data = b''.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 encoding:
+ out_data = out_data.decode(encoding)
+ err_data = err_data.decode(encoding)
- if 0 != exit_status:
- raise exceptions.SSHExecCommandFailed(
- command=cmd, exit_status=exit_status,
- stderr=err_data, stdout=out_data)
- return out_data
+ if 0 != exit_status:
+ raise exceptions.SSHExecCommandFailed(
+ command=cmd, exit_status=exit_status,
+ stderr=err_data, stdout=out_data)
+ return out_data
def test_connection_auth(self):
"""Raises an exception when we can not connect to server via ssh."""
diff --git a/tempest/tests/lib/test_ssh.py b/tempest/tests/lib/test_ssh.py
index f6efd47..d001c51 100644
--- a/tempest/tests/lib/test_ssh.py
+++ b/tempest/tests/lib/test_ssh.py
@@ -141,8 +141,6 @@
def test_exec_command(self):
chan_mock, poll_mock, select_mock = (
self._set_mocks_for_select([[1, 0, 0]], True))
- closed_prop = mock.PropertyMock(return_value=True)
- type(chan_mock).closed = closed_prop
chan_mock.recv_exit_status.return_value = 0
chan_mock.recv.return_value = b''
@@ -164,7 +162,6 @@
chan_mock.recv_stderr_ready.assert_called_once_with()
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 _set_mocks_for_select(self, poll_data, ito_value=False):
gsc_mock = self.patch('tempest.lib.common.ssh.Client.'
@@ -184,7 +181,7 @@
gsc_mock.return_value = client_mock
ito_mock.return_value = ito_value
client_mock.get_transport.return_value = tran_mock
- tran_mock.open_session.return_value = chan_mock
+ tran_mock.open_session().__enter__.return_value = chan_mock
if isinstance(poll_data[0], list):
poll_mock.poll.side_effect = poll_data
else:
@@ -242,7 +239,7 @@
gsc_mock.return_value = client_mock
client_mock.get_transport.return_value = tran_mock
- tran_mock.open_session.return_value = chan_mock
+ tran_mock.open_session().__enter__.return_value = chan_mock
chan_mock.recv_exit_status.return_value = 0
std_out_mock = mock.MagicMock(StringIO)