1 # Copyright (c) 2019 Cisco and/or its affiliates.
2 # Licensed under the Apache License, Version 2.0 (the "License");
3 # you may not use this file except in compliance with the License.
4 # You may obtain a copy of the License at:
6 # http://www.apache.org/licenses/LICENSE-2.0
8 # Unless required by applicable law or agreed to in writing, software
9 # distributed under the License is distributed on an "AS IS" BASIS,
10 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
11 # See the License for the specific language governing permissions and
12 # limitations under the License.
14 """Library for SSH connection management."""
20 from time import time, sleep
22 from paramiko import RSAKey, SSHClient, AutoAddPolicy
23 from paramiko.ssh_exception import SSHException, NoValidConnectionsError
24 from robot.api import logger
25 from scp import SCPClient, SCPException
28 __all__ = ["exec_cmd", "exec_cmd_no_error"]
33 class SSHTimeout(Exception):
34 """This exception is raised when a timeout occurs."""
39 """Contains methods for managing and using SSH connections."""
41 __MAX_RECV_BUF = 10*1024*1024
42 __existing_connections = {}
50 """Get IP address and port hash from node dictionary.
52 :param node: Node in topology.
54 :returns: IP address and port for the specified node.
58 return hash(frozenset([node['host'], node['port']]))
60 def connect(self, node, attempts=5):
61 """Connect to node prior to running exec_command or scp.
63 If there already is a connection to the node, this method reuses it.
65 :param node: Node in topology.
66 :param attempts: Number of reconnect attempts.
69 :raises IOError: If cannot connect to host.
72 node_hash = self._node_hash(node)
73 if node_hash in SSH.__existing_connections:
74 self._ssh = SSH.__existing_connections[node_hash]
75 if self._ssh.get_transport().is_active():
76 logger.debug('Reusing SSH: {ssh}'.format(ssh=self._ssh))
79 self._reconnect(attempts-1)
81 raise IOError('Cannot connect to {host}'.
82 format(host=node['host']))
87 if 'priv_key' in node:
88 pkey = RSAKey.from_private_key(
89 StringIO.StringIO(node['priv_key']))
91 self._ssh = SSHClient()
92 self._ssh.set_missing_host_key_policy(AutoAddPolicy())
94 self._ssh.connect(node['host'], username=node['username'],
95 password=node.get('password'), pkey=pkey,
98 self._ssh.get_transport().set_keepalive(10)
100 SSH.__existing_connections[node_hash] = self._ssh
101 logger.debug('New SSH to {peer} took {total} seconds: {ssh}'.
103 peer=self._ssh.get_transport().getpeername(),
104 total=(time() - start),
107 raise IOError('Cannot connect to {host}'.
108 format(host=node['host']))
109 except NoValidConnectionsError as err:
110 logger.error(repr(err))
111 raise IOError('Unable to connect to port {port} on {host}'.
112 format(port=node['port'], host=node['host']))
114 def disconnect(self, node):
115 """Close SSH connection to the node.
117 :param node: The node to disconnect from.
120 node_hash = self._node_hash(node)
121 if node_hash in SSH.__existing_connections:
122 logger.debug('Disconnecting peer: {host}, {port}'.
123 format(host=node['host'], port=node['port']))
124 ssh = SSH.__existing_connections.pop(node_hash)
127 def _reconnect(self, attempts=0):
128 """Close the SSH connection and open it again.
130 :param attempts: Number of reconnect attempts.
134 self.disconnect(node)
135 self.connect(node, attempts)
136 logger.debug('Reconnecting peer done: {host}, {port}'.
137 format(host=node['host'], port=node['port']))
139 def exec_command(self, cmd, timeout=10):
140 """Execute SSH command on a new channel on the connected Node.
142 :param cmd: Command to run on the Node.
143 :param timeout: Maximal time in seconds to wait until the command is
144 done. If set to None then wait forever.
147 :return return_code, stdout, stderr
148 :rtype: tuple(int, str, str)
149 :raise SSHTimeout: If command is not finished in timeout time.
151 stdout = StringIO.StringIO()
152 stderr = StringIO.StringIO()
154 chan = self._ssh.get_transport().open_session(timeout=5)
155 peer = self._ssh.get_transport().getpeername()
156 except AttributeError:
158 chan = self._ssh.get_transport().open_session(timeout=5)
159 peer = self._ssh.get_transport().getpeername()
162 chan = self._ssh.get_transport().open_session(timeout=5)
163 peer = self._ssh.get_transport().getpeername()
164 chan.settimeout(timeout)
166 logger.trace('exec_command on {peer} with timeout {timeout}: {cmd}'
167 .format(peer=peer, timeout=timeout, cmd=cmd))
170 chan.exec_command(cmd)
171 while not chan.exit_status_ready() and timeout is not None:
172 if chan.recv_ready():
173 stdout.write(chan.recv(self.__MAX_RECV_BUF))
175 if chan.recv_stderr_ready():
176 stderr.write(chan.recv_stderr(self.__MAX_RECV_BUF))
178 if time() - start > timeout:
180 'Timeout exception during execution of command: {cmd}\n'
181 'Current contents of stdout buffer: {stdout}\n'
182 'Current contents of stderr buffer: {stderr}\n'
183 .format(cmd=cmd, stdout=stdout.getvalue(),
184 stderr=stderr.getvalue())
188 return_code = chan.recv_exit_status()
190 while chan.recv_ready():
191 stdout.write(chan.recv(self.__MAX_RECV_BUF))
193 while chan.recv_stderr_ready():
194 stderr.write(chan.recv_stderr(self.__MAX_RECV_BUF))
197 logger.trace('exec_command on {peer} took {total} seconds'.
198 format(peer=peer, total=end-start))
200 logger.trace('return RC {rc}'.format(rc=return_code))
201 logger.trace('return STDOUT {stdout}'.format(stdout=stdout.getvalue()))
202 logger.trace('return STDERR {stderr}'.format(stderr=stderr.getvalue()))
203 return return_code, stdout.getvalue(), stderr.getvalue()
205 def exec_command_sudo(self, cmd, cmd_input=None, timeout=30):
206 """Execute SSH command with sudo on a new channel on the connected Node.
208 :param cmd: Command to be executed.
209 :param cmd_input: Input redirected to the command.
210 :param timeout: Timeout.
211 :returns: return_code, stdout, stderr
215 >>> from ssh import SSH
217 >>> ssh.connect(node)
218 >>> # Execute command without input (sudo -S cmd)
219 >>> ssh.exec_command_sudo("ifconfig eth0 down")
220 >>> # Execute command with input (sudo -S cmd <<< "input")
221 >>> ssh.exec_command_sudo("vpp_api_test", "dump_interface_table")
223 if cmd_input is None:
224 command = 'sudo -S {c}'.format(c=cmd)
226 command = 'sudo -S {c} <<< "{i}"'.format(c=cmd, i=cmd_input)
227 return self.exec_command(command, timeout)
229 def exec_command_lxc(self, lxc_cmd, lxc_name, lxc_params='', sudo=True,
231 """Execute command in LXC on a new SSH channel on the connected Node.
233 :param lxc_cmd: Command to be executed.
234 :param lxc_name: LXC name.
235 :param lxc_params: Additional parameters for LXC attach.
236 :param sudo: Run in privileged LXC mode. Default: privileged
237 :param timeout: Timeout.
240 :type lxc_params: str
243 :returns: return_code, stdout, stderr
245 command = "lxc-attach {p} --name {n} -- /bin/sh -c '{c}'"\
246 .format(p=lxc_params, n=lxc_name, c=lxc_cmd)
249 command = 'sudo -S {c}'.format(c=command)
250 return self.exec_command(command, timeout)
252 def interactive_terminal_open(self, time_out=45):
253 """Open interactive terminal on a new channel on the connected Node.
255 :param time_out: Timeout in seconds.
256 :returns: SSH channel with opened terminal.
258 .. warning:: Interruptingcow is used here, and it uses
259 signal(SIGALRM) to let the operating system interrupt program
260 execution. This has the following limitations: Python signal
261 handlers only apply to the main thread, so you cannot use this
262 from other threads. You must not use this in a program that
263 uses SIGALRM itself (this includes certain profilers)
265 chan = self._ssh.get_transport().open_session()
268 chan.settimeout(int(time_out))
269 chan.set_combine_stderr(True)
272 while not buf.endswith((":~# ", ":~$ ", "~]$ ", "~]# ")):
274 chunk = chan.recv(self.__MAX_RECV_BUF)
278 if chan.exit_status_ready():
279 logger.error('Channel exit status ready')
281 except socket.timeout:
282 logger.error('Socket timeout: {0}'.format(buf))
283 raise Exception('Socket timeout: {0}'.format(buf))
286 def interactive_terminal_exec_command(self, chan, cmd, prompt):
287 """Execute command on interactive terminal.
289 interactive_terminal_open() method has to be called first!
291 :param chan: SSH channel with opened terminal.
292 :param cmd: Command to be executed.
293 :param prompt: Command prompt, sequence of characters used to
294 indicate readiness to accept commands.
295 :returns: Command output.
297 .. warning:: Interruptingcow is used here, and it uses
298 signal(SIGALRM) to let the operating system interrupt program
299 execution. This has the following limitations: Python signal
300 handlers only apply to the main thread, so you cannot use this
301 from other threads. You must not use this in a program that
302 uses SIGALRM itself (this includes certain profilers)
304 chan.sendall('{c}\n'.format(c=cmd))
306 while not buf.endswith(prompt):
308 chunk = chan.recv(self.__MAX_RECV_BUF)
312 if chan.exit_status_ready():
313 logger.error('Channel exit status ready')
315 except socket.timeout:
316 logger.error('Socket timeout during execution of command: '
317 '{0}\nBuffer content:\n{1}'.format(cmd, buf))
318 raise Exception('Socket timeout during execution of command: '
319 '{0}\nBuffer content:\n{1}'.format(cmd, buf))
320 tmp = buf.replace(cmd.replace('\n', ''), '')
322 tmp.replace(item, '')
326 def interactive_terminal_close(chan):
327 """Close interactive terminal SSH channel.
329 :param chan: SSH channel to be closed.
333 def scp(self, local_path, remote_path, get=False, timeout=30,
335 """Copy files from local_path to remote_path or vice versa.
337 connect() method has to be called first!
339 :param local_path: Path to local file that should be uploaded; or
340 path where to save remote file.
341 :param remote_path: Remote path where to place uploaded file; or
342 path to remote file which should be downloaded.
343 :param get: scp operation to perform. Default is put.
344 :param timeout: Timeout value in seconds.
345 :param wildcard: If path has wildcard characters. Default is false.
346 :type local_path: str
347 :type remote_path: str
353 logger.trace('SCP {0} to {1}:{2}'.format(
354 local_path, self._ssh.get_transport().getpeername(),
357 logger.trace('SCP {0}:{1} to {2}'.format(
358 self._ssh.get_transport().getpeername(), remote_path,
360 # SCPCLient takes a paramiko transport as its only argument
362 scp = SCPClient(self._ssh.get_transport(), socket_timeout=timeout)
364 scp = SCPClient(self._ssh.get_transport(), sanitize=lambda x: x,
365 socket_timeout=timeout)
368 scp.put(local_path, remote_path)
370 scp.get(remote_path, local_path)
373 logger.trace('SCP took {0} seconds'.format(end-start))
376 def exec_cmd(node, cmd, timeout=600, sudo=False):
377 """Convenience function to ssh/exec/return rc, out & err.
379 Returns (rc, stdout, stderr).
381 :param node: The node to execute command on.
382 :param cmd: Command to execute.
383 :param timeout: Timeout value in seconds. Default: 600.
384 :param sudo: Sudo privilege execution flag. Default: False.
389 :returns: RC, Stdout, Stderr.
390 :rtype: tuple(int, str, str)
393 raise TypeError('Node parameter is None')
395 raise TypeError('Command parameter is None')
397 raise ValueError('Empty command parameter')
401 if node.get('host_port') is not None:
403 ssh_node['host'] = '127.0.0.1'
404 ssh_node['port'] = node['port']
405 ssh_node['username'] = node['username']
406 ssh_node['password'] = node['password']
408 options = '-o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null'
409 tnl = '-L {port}:127.0.0.1:{port}'.format(port=node['port'])
410 ssh_cmd = 'ssh {tnl} {op} {user}@{host} -p {host_port}'.\
411 format(tnl=tnl, op=options, user=node['host_username'],
412 host=node['host'], host_port=node['host_port'])
413 logger.trace('Initializing local port forwarding:\n{ssh_cmd}'.
414 format(ssh_cmd=ssh_cmd))
415 child = pexpect.spawn(ssh_cmd)
416 child.expect('.* password: ')
417 logger.trace(child.after)
418 child.sendline(node['host_password'])
419 child.expect('Welcome .*')
420 logger.trace(child.after)
421 logger.trace('Local port forwarding finished.')
426 ssh.connect(ssh_node)
427 except SSHException as err:
428 logger.error("Failed to connect to node" + repr(err))
429 return None, None, None
433 (ret_code, stdout, stderr) = ssh.exec_command(cmd, timeout=timeout)
435 (ret_code, stdout, stderr) = ssh.exec_command_sudo(cmd,
437 except SSHException as err:
438 logger.error(repr(err))
439 return None, None, None
441 return ret_code, stdout, stderr
444 def exec_cmd_no_error(node, cmd, timeout=600, sudo=False, message=None):
445 """Convenience function to ssh/exec/return out & err.
447 Verifies that return code is zero.
449 :param node: DUT node.
450 :param cmd: Command to be executed.
451 :param timeout: Timeout value in seconds. Default: 600.
452 :param sudo: Sudo privilege execution flag. Default: False.
453 :param message: Error message in case of failure. Default: None.
459 :returns: Stdout, Stderr.
460 :rtype: tuple(str, str)
461 :raises RuntimeError: If bash return code is not 0.
463 ret_code, stdout, stderr = exec_cmd(node, cmd, timeout=timeout, sudo=sudo)
464 msg = ('Command execution failed: "{cmd}"\n{stderr}'.
465 format(cmd=cmd, stderr=stderr) if message is None else message)
467 raise RuntimeError(msg)
469 return stdout, stderr
471 def scp_node(node, local_path, remote_path, get=False, timeout=30):
472 """Copy files from local_path to remote_path or vice versa.
474 :param node: SUT node.
475 :param local_path: Path to local file that should be uploaded; or
476 path where to save remote file.
477 :param remote_path: Remote path where to place uploaded file; or
478 path to remote file which should be downloaded.
479 :param get: scp operation to perform. Default is put.
480 :param timeout: Timeout value in seconds.
482 :type local_path: str
483 :type remote_path: str
486 :raises RuntimeError: If SSH connection failed or SCP transfer failed.
493 raise RuntimeError('Failed to connect to {host}!'
494 .format(host=node['host']))
496 ssh.scp(local_path, remote_path, get, timeout)
498 raise RuntimeError('SCP execution failed on {host}!'
499 .format(host=node['host']))