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Diffstat (limited to 'tempest_lib/common/ssh.py')
| -rw-r--r-- | tempest_lib/common/ssh.py | 152 |
1 files changed, 152 insertions, 0 deletions
diff --git a/tempest_lib/common/ssh.py b/tempest_lib/common/ssh.py new file mode 100644 index 0000000..6ee0daf --- /dev/null +++ b/tempest_lib/common/ssh.py @@ -0,0 +1,152 @@ +# Copyright 2012 OpenStack Foundation +# All Rights Reserved. +# +# Licensed under the Apache License, Version 2.0 (the "License"); you may +# not use this file except in compliance with the License. You may obtain +# a copy of the License at +# +# http://www.apache.org/licenses/LICENSE-2.0 +# +# Unless required by applicable law or agreed to in writing, software +# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT +# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the +# License for the specific language governing permissions and limitations +# under the License. + + +import select +import socket +import time +import warnings + +from oslo_log import log as logging +import six + +from tempest_lib import exceptions + + +with warnings.catch_warnings(): + warnings.simplefilter("ignore") + import paramiko + + +LOG = logging.getLogger(__name__) + + +class Client(object): + + def __init__(self, host, username, password=None, timeout=300, pkey=None, + channel_timeout=10, look_for_keys=False, key_filename=None): + self.host = host + self.username = username + self.password = password + if isinstance(pkey, six.string_types): + pkey = paramiko.RSAKey.from_private_key( + six.StringIO(str(pkey))) + self.pkey = pkey + self.look_for_keys = look_for_keys + self.key_filename = key_filename + self.timeout = int(timeout) + self.channel_timeout = float(channel_timeout) + self.buf_size = 1024 + + def _get_ssh_connection(self, sleep=1.5, backoff=1): + """Returns an ssh connection to the specified host.""" + bsleep = sleep + ssh = paramiko.SSHClient() + ssh.set_missing_host_key_policy( + paramiko.AutoAddPolicy()) + _start_time = time.time() + if self.pkey is not None: + LOG.info("Creating ssh connection to '%s' as '%s'" + " with public key authentication", + self.host, self.username) + else: + LOG.info("Creating ssh connection to '%s' as '%s'" + " with password %s", + self.host, self.username, str(self.password)) + attempts = 0 + while True: + try: + ssh.connect(self.host, username=self.username, + password=self.password, + look_for_keys=self.look_for_keys, + key_filename=self.key_filename, + timeout=self.channel_timeout, pkey=self.pkey) + LOG.info("ssh connection to %s@%s successfuly created", + self.username, self.host) + return ssh + except (socket.error, + paramiko.SSHException) as e: + if self._is_timed_out(_start_time): + LOG.exception("Failed to establish authenticated ssh" + " connection to %s@%s after %d attempts", + self.username, self.host, attempts) + raise exceptions.SSHTimeout(host=self.host, + user=self.username, + password=self.password) + bsleep += backoff + attempts += 1 + LOG.warning("Failed to establish authenticated ssh" + " connection to %s@%s (%s). Number attempts: %s." + " Retry after %d seconds.", + self.username, self.host, e, attempts, bsleep) + time.sleep(bsleep) + + def _is_timed_out(self, start_time): + return (time.time() - self.timeout) > start_time + + def exec_command(self, cmd): + """Execute the specified command on the server + + Note that this method is reading whole command outputs to memory, thus + shouldn't be used for large outputs. + + :param str cmd: Command to run at remote server. + :returns: data read from standard output of the command. + :raises: SSHExecCommandFailed if command returns nonzero + status. The exception contains command status stderr content. + :raises: TimeoutException if cmd doesn't end when timeout expires. + """ + 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() + out_data = [] + err_data = [] + 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): + 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 += out_chunk, + if channel.recv_stderr_ready(): + err_chunk = channel.recv_stderr(self.buf_size) + err_data += err_chunk, + if channel.closed and not err_chunk and not out_chunk: + break + exit_status = channel.recv_exit_status() + if 0 != exit_status: + raise exceptions.SSHExecCommandFailed( + command=cmd, exit_status=exit_status, + strerror=''.join(err_data)) + return ''.join(out_data) + + def test_connection_auth(self): + """Raises an exception when we can not connect to server via ssh.""" + connection = self._get_ssh_connection() + connection.close() |