-# Copyright (c) 2016 Cisco and/or its affiliates.
+# Copyright (c) 2019 Cisco and/or its affiliates.
# 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:
# See the License for the specific language governing permissions and
# limitations under the License.
-import StringIO
-from time import time
+"""Library for SSH connection management."""
+
import socket
-import paramiko
-from paramiko import RSAKey
-from scp import SCPClient
-from interruptingcow import timeout
+import StringIO
+
+from time import time, sleep
+
+from paramiko import RSAKey, SSHClient, AutoAddPolicy
+from paramiko.ssh_exception import SSHException, NoValidConnectionsError
from robot.api import logger
-from robot.utils.asserts import assert_equal
+from scp import SCPClient, SCPException
+
__all__ = ["exec_cmd", "exec_cmd_no_error"]
# TODO: load priv key
+class SSHTimeout(Exception):
+ """This exception is raised when a timeout occurs."""
+ pass
+
+
class SSH(object):
+ """Contains methods for managing and using SSH connections."""
__MAX_RECV_BUF = 10*1024*1024
__existing_connections = {}
def __init__(self):
self._ssh = None
+ self._node = None
@staticmethod
def _node_hash(node):
+ """Get IP address and port hash from node dictionary.
+
+ :param node: Node in topology.
+ :type node: dict
+ :returns: IP address and port for the specified node.
+ :rtype: int
+ """
+
return hash(frozenset([node['host'], node['port']]))
- def connect(self, node):
+ def connect(self, node, attempts=5):
"""Connect to node prior to running exec_command or scp.
If there already is a connection to the node, this method reuses it.
+
+ :param node: Node in topology.
+ :param attempts: Number of reconnect attempts.
+ :type node: dict
+ :type attempts: int
+ :raises IOError: If cannot connect to host.
"""
+ self._node = node
node_hash = self._node_hash(node)
if node_hash in SSH.__existing_connections:
self._ssh = SSH.__existing_connections[node_hash]
- logger.debug('reusing ssh: {0}'.format(self._ssh))
+ if self._ssh.get_transport().is_active():
+ logger.debug('Reusing SSH: {ssh}'.format(ssh=self._ssh))
+ else:
+ if attempts > 0:
+ self._reconnect(attempts-1)
+ else:
+ raise IOError('Cannot connect to {host}'.
+ format(host=node['host']))
else:
- start = time()
- pkey = None
- if 'priv_key' in node:
- pkey = RSAKey.from_private_key(
+ try:
+ start = time()
+ pkey = None
+ if 'priv_key' in node:
+ pkey = RSAKey.from_private_key(
StringIO.StringIO(node['priv_key']))
- self._ssh = paramiko.SSHClient()
- self._ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())
-
- self._ssh.connect(node['host'], username=node['username'],
- password=node.get('password'), pkey=pkey,
- port=node['port'])
-
- SSH.__existing_connections[node_hash] = self._ssh
-
- logger.trace('connect took {} seconds'.format(time() - start))
- logger.debug('new ssh: {0}'.format(self._ssh))
-
- logger.debug('Connect peer: {0}'.
- format(self._ssh.get_transport().getpeername()))
- logger.debug('Connections: {0}'.format(str(SSH.__existing_connections)))
-
- def disconnect(self, node):
+ self._ssh = SSHClient()
+ self._ssh.set_missing_host_key_policy(AutoAddPolicy())
+
+ self._ssh.connect(node['host'], username=node['username'],
+ password=node.get('password'), pkey=pkey,
+ port=node['port'])
+
+ self._ssh.get_transport().set_keepalive(10)
+
+ SSH.__existing_connections[node_hash] = self._ssh
+ logger.debug('New SSH to {peer} took {total} seconds: {ssh}'.
+ format(
+ peer=self._ssh.get_transport().getpeername(),
+ total=(time() - start),
+ ssh=self._ssh))
+ except SSHException:
+ raise IOError('Cannot connect to {host}'.
+ format(host=node['host']))
+ except NoValidConnectionsError as err:
+ logger.error(repr(err))
+ raise IOError('Unable to connect to port {port} on {host}'.
+ format(port=node['port'], host=node['host']))
+
+ def disconnect(self, node=None):
"""Close SSH connection to the node.
- :param node: The node to disconnect from.
- :type node: dict
+ :param node: The node to disconnect from. None means last connected.
+ :type node: dict or None
"""
+ if node is None:
+ node = self._node
+ if node is None:
+ return
node_hash = self._node_hash(node)
if node_hash in SSH.__existing_connections:
+ logger.debug('Disconnecting peer: {host}, {port}'.
+ format(host=node['host'], port=node['port']))
ssh = SSH.__existing_connections.pop(node_hash)
ssh.close()
- def exec_command(self, cmd, timeout=10):
- """Execute SSH command on a new channel on the connected Node.
+ def _reconnect(self, attempts=0):
+ """Close the SSH connection and open it again.
- Returns (return_code, stdout, stderr).
+ :param attempts: Number of reconnect attempts.
+ :type attempts: int
"""
- logger.trace('exec_command on {0}: {1}'
- .format(self._ssh.get_transport().getpeername(), cmd))
- start = time()
- chan = self._ssh.get_transport().open_session()
- if timeout is not None:
- chan.settimeout(int(timeout))
- chan.exec_command(cmd)
- end = time()
- logger.trace('exec_command on {0} took {1} seconds'.format(
- self._ssh.get_transport().getpeername(), end-start))
+ node = self._node
+ self.disconnect(node)
+ self.connect(node, attempts)
+ logger.debug('Reconnecting peer done: {host}, {port}'.
+ format(host=node['host'], port=node['port']))
+
+ def exec_command(self, cmd, timeout=10, log_stdout_err=True):
+ """Execute SSH command on a new channel on the connected Node.
- stdout = ""
+ :param cmd: Command to run on the Node.
+ :param timeout: Maximal time in seconds to wait until the command is
+ done. If set to None then wait forever.
+ :param log_stdout_err: If True, stdout and stderr are logged. stdout
+ and stderr are logged also if the return code is not zero
+ independently of the value of log_stdout_err.
+ :type cmd: str or OptionString
+ :type timeout: int
+ :type log_stdout_err: bool
+ :returns: return_code, stdout, stderr
+ :rtype: tuple(int, str, str)
+ :raises SSHTimeout: If command is not finished in timeout time.
+ """
+ cmd = str(cmd)
+ stdout = StringIO.StringIO()
+ stderr = StringIO.StringIO()
try:
- while True:
- buf = chan.recv(self.__MAX_RECV_BUF)
- stdout += buf
- if not buf:
- break
- except socket.timeout:
- logger.error('Caught timeout exception, current contents '
- 'of buffer: {0}'.format(stdout))
- raise
-
- stderr = ""
- while True:
- buf = chan.recv_stderr(self.__MAX_RECV_BUF)
- stderr += buf
- if not buf:
- break
+ chan = self._ssh.get_transport().open_session(timeout=5)
+ peer = self._ssh.get_transport().getpeername()
+ except AttributeError:
+ self._reconnect()
+ chan = self._ssh.get_transport().open_session(timeout=5)
+ peer = self._ssh.get_transport().getpeername()
+ except SSHException:
+ self._reconnect()
+ chan = self._ssh.get_transport().open_session(timeout=5)
+ peer = self._ssh.get_transport().getpeername()
+ chan.settimeout(timeout)
+
+ logger.trace('exec_command on {peer} with timeout {timeout}: {cmd}'
+ .format(peer=peer, timeout=timeout, cmd=cmd))
+ start = time()
+ chan.exec_command(cmd)
+ while not chan.exit_status_ready() and timeout is not None:
+ if chan.recv_ready():
+ stdout.write(chan.recv(self.__MAX_RECV_BUF))
+
+ if chan.recv_stderr_ready():
+ stderr.write(chan.recv_stderr(self.__MAX_RECV_BUF))
+
+ if time() - start > timeout:
+ raise SSHTimeout(
+ 'Timeout exception during execution of command: {cmd}\n'
+ 'Current contents of stdout buffer: {stdout}\n'
+ 'Current contents of stderr buffer: {stderr}\n'
+ .format(cmd=cmd, stdout=stdout.getvalue(),
+ stderr=stderr.getvalue())
+ )
+
+ sleep(0.1)
return_code = chan.recv_exit_status()
- logger.trace('chan_recv/_stderr took {} seconds'.format(time()-end))
- logger.trace('return RC {}'.format(return_code))
- logger.trace('return STDOUT {}'.format(stdout))
- logger.trace('return STDERR {}'.format(stderr))
- return return_code, stdout, stderr
+ while chan.recv_ready():
+ stdout.write(chan.recv(self.__MAX_RECV_BUF))
+
+ while chan.recv_stderr_ready():
+ stderr.write(chan.recv_stderr(self.__MAX_RECV_BUF))
- def exec_command_sudo(self, cmd, cmd_input=None, timeout=10):
+ end = time()
+ logger.trace('exec_command on {peer} took {total} seconds'.
+ format(peer=peer, total=end-start))
+
+ logger.trace('return RC {rc}'.format(rc=return_code))
+ if log_stdout_err or int(return_code):
+ logger.trace('return STDOUT {stdout}'.
+ format(stdout=stdout.getvalue()))
+ logger.trace('return STDERR {stderr}'.
+ format(stderr=stderr.getvalue()))
+ return return_code, stdout.getvalue(), stderr.getvalue()
+
+ def exec_command_sudo(self, cmd, cmd_input=None, timeout=30,
+ log_stdout_err=True):
"""Execute SSH command with sudo on a new channel on the connected Node.
:param cmd: Command to be executed.
:param cmd_input: Input redirected to the command.
:param timeout: Timeout.
- :return: return_code, stdout, stderr
+ :param log_stdout_err: If True, stdout and stderr are logged.
+ :type cmd: str
+ :type cmd_input: str
+ :type timeout: int
+ :type log_stdout_err: bool
+ :returns: return_code, stdout, stderr
+ :rtype: tuple(int, str, str)
:Example:
command = 'sudo -S {c}'.format(c=cmd)
else:
command = 'sudo -S {c} <<< "{i}"'.format(c=cmd, i=cmd_input)
+ return self.exec_command(command, timeout,
+ log_stdout_err=log_stdout_err)
+
+ def exec_command_lxc(self, lxc_cmd, lxc_name, lxc_params='', sudo=True,
+ timeout=30):
+ """Execute command in LXC on a new SSH channel on the connected Node.
+
+ :param lxc_cmd: Command to be executed.
+ :param lxc_name: LXC name.
+ :param lxc_params: Additional parameters for LXC attach.
+ :param sudo: Run in privileged LXC mode. Default: privileged
+ :param timeout: Timeout.
+ :type lxc_cmd: str
+ :type lxc_name: str
+ :type lxc_params: str
+ :type sudo: bool
+ :type timeout: int
+ :returns: return_code, stdout, stderr
+ """
+ command = "lxc-attach {p} --name {n} -- /bin/sh -c '{c}'"\
+ .format(p=lxc_params, n=lxc_name, c=lxc_cmd)
+
+ if sudo:
+ command = 'sudo -S {c}'.format(c=command)
return self.exec_command(command, timeout)
- def interactive_terminal_open(self, time_out=10):
+ def interactive_terminal_open(self, time_out=45):
"""Open interactive terminal on a new channel on the connected Node.
:param time_out: Timeout in seconds.
- :return: SSH channel with opened terminal.
+ :returns: SSH channel with opened terminal.
.. warning:: Interruptingcow is used here, and it uses
signal(SIGALRM) to let the operating system interrupt program
chan.get_pty()
chan.invoke_shell()
chan.settimeout(int(time_out))
+ chan.set_combine_stderr(True)
buf = ''
- try:
- with timeout(time_out, exception=RuntimeError):
- while not buf.endswith(':~$ '):
- if chan.recv_ready():
- buf = chan.recv(4096)
- except RuntimeError:
- raise Exception('Open interactive terminal timeout.')
+ while not buf.endswith((":~# ", ":~$ ", "~]$ ", "~]# ")):
+ try:
+ chunk = chan.recv(self.__MAX_RECV_BUF)
+ if not chunk:
+ break
+ buf += chunk
+ if chan.exit_status_ready():
+ logger.error('Channel exit status ready')
+ break
+ except socket.timeout:
+ logger.error('Socket timeout: {0}'.format(buf))
+ raise Exception('Socket timeout: {0}'.format(buf))
return chan
- @staticmethod
- def interactive_terminal_exec_command(chan, cmd, prompt,
- time_out=10):
+ def interactive_terminal_exec_command(self, chan, cmd, prompt):
"""Execute command on interactive terminal.
interactive_terminal_open() method has to be called first!
:param cmd: Command to be executed.
:param prompt: Command prompt, sequence of characters used to
indicate readiness to accept commands.
- :param time_out: Timeout in seconds.
- :return: Command output.
+ :returns: Command output.
.. warning:: Interruptingcow is used here, and it uses
signal(SIGALRM) to let the operating system interrupt program
"""
chan.sendall('{c}\n'.format(c=cmd))
buf = ''
- try:
- with timeout(time_out, exception=RuntimeError):
- while not buf.endswith(prompt):
- if chan.recv_ready():
- buf += chan.recv(4096)
- except RuntimeError:
- raise Exception("Exec '{c}' timeout.".format(c=cmd))
+ while not buf.endswith(prompt):
+ try:
+ chunk = chan.recv(self.__MAX_RECV_BUF)
+ if not chunk:
+ break
+ buf += chunk
+ if chan.exit_status_ready():
+ logger.error('Channel exit status ready')
+ break
+ except socket.timeout:
+ logger.error('Socket timeout during execution of command: '
+ '{0}\nBuffer content:\n{1}'.format(cmd, buf))
+ raise Exception('Socket timeout during execution of command: '
+ '{0}\nBuffer content:\n{1}'.format(cmd, buf))
tmp = buf.replace(cmd.replace('\n', ''), '')
- return tmp.replace(prompt, '')
+ for item in prompt:
+ tmp.replace(item, '')
+ return tmp
@staticmethod
def interactive_terminal_close(chan):
"""Close interactive terminal SSH channel.
- :param: chan: SSH channel to be closed.
+ :param chan: SSH channel to be closed.
"""
chan.close()
- def scp(self, local_path, remote_path):
- """Copy files from local_path to remote_path.
+ def scp(self, local_path, remote_path, get=False, timeout=30,
+ wildcard=False):
+ """Copy files from local_path to remote_path or vice versa.
connect() method has to be called first!
+
+ :param local_path: Path to local file that should be uploaded; or
+ path where to save remote file.
+ :param remote_path: Remote path where to place uploaded file; or
+ path to remote file which should be downloaded.
+ :param get: scp operation to perform. Default is put.
+ :param timeout: Timeout value in seconds.
+ :param wildcard: If path has wildcard characters. Default is false.
+ :type local_path: str
+ :type remote_path: str
+ :type get: bool
+ :type timeout: int
+ :type wildcard: bool
"""
- logger.trace('SCP {0} to {1}:{2}'.format(
- local_path, self._ssh.get_transport().getpeername(), remote_path))
+ if not get:
+ logger.trace('SCP {0} to {1}:{2}'.format(
+ local_path, self._ssh.get_transport().getpeername(),
+ remote_path))
+ else:
+ logger.trace('SCP {0}:{1} to {2}'.format(
+ self._ssh.get_transport().getpeername(), remote_path,
+ local_path))
# SCPCLient takes a paramiko transport as its only argument
- scp = SCPClient(self._ssh.get_transport())
+ if not wildcard:
+ scp = SCPClient(self._ssh.get_transport(), socket_timeout=timeout)
+ else:
+ scp = SCPClient(self._ssh.get_transport(), sanitize=lambda x: x,
+ socket_timeout=timeout)
start = time()
- scp.put(local_path, remote_path)
+ if not get:
+ scp.put(local_path, remote_path)
+ else:
+ scp.get(remote_path, local_path)
scp.close()
end = time()
logger.trace('SCP took {0} seconds'.format(end-start))
-def exec_cmd(node, cmd, timeout=None, sudo=False):
+def exec_cmd(node, cmd, timeout=600, sudo=False, disconnect=False):
"""Convenience function to ssh/exec/return rc, out & err.
Returns (rc, stdout, stderr).
+
+ :param node: The node to execute command on.
+ :param cmd: Command to execute.
+ :param timeout: Timeout value in seconds. Default: 600.
+ :param sudo: Sudo privilege execution flag. Default: False.
+ :param disconnect: Close the opened SSH connection if True.
+ :type node: dict
+ :type cmd: str or OptionString
+ :type timeout: int
+ :type sudo: bool
+ :type disconnect: bool
+ :returns: RC, Stdout, Stderr.
+ :rtype: tuple(int, str, str)
"""
if node is None:
raise TypeError('Node parameter is None')
if cmd is None:
raise TypeError('Command parameter is None')
- if len(cmd) == 0:
+ if not cmd:
raise ValueError('Empty command parameter')
ssh = SSH()
+
+ if node.get('host_port') is not None:
+ ssh_node = dict()
+ ssh_node['host'] = '127.0.0.1'
+ ssh_node['port'] = node['port']
+ ssh_node['username'] = node['username']
+ ssh_node['password'] = node['password']
+ import pexpect
+ options = '-o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null'
+ tnl = '-L {port}:127.0.0.1:{port}'.format(port=node['port'])
+ ssh_cmd = 'ssh {tnl} {op} {user}@{host} -p {host_port}'.\
+ format(tnl=tnl, op=options, user=node['host_username'],
+ host=node['host'], host_port=node['host_port'])
+ logger.trace('Initializing local port forwarding:\n{ssh_cmd}'.
+ format(ssh_cmd=ssh_cmd))
+ child = pexpect.spawn(ssh_cmd)
+ child.expect('.* password: ')
+ logger.trace(child.after)
+ child.sendline(node['host_password'])
+ child.expect('Welcome .*')
+ logger.trace(child.after)
+ logger.trace('Local port forwarding finished.')
+ else:
+ ssh_node = node
+
try:
- ssh.connect(node)
- except Exception, e:
- logger.error("Failed to connect to node" + str(e))
- return None
+ ssh.connect(ssh_node)
+ except SSHException as err:
+ logger.error("Failed to connect to node" + repr(err))
+ return None, None, None
try:
if not sudo:
else:
(ret_code, stdout, stderr) = ssh.exec_command_sudo(cmd,
timeout=timeout)
- except Exception, e:
- logger.error(e)
- return None
+ except SSHException as err:
+ logger.error(repr(err))
+ return None, None, None
+ finally:
+ if disconnect:
+ ssh.disconnect()
return ret_code, stdout, stderr
-def exec_cmd_no_error(node, cmd, timeout=None, sudo=False):
+def exec_cmd_no_error(
+ node, cmd, timeout=600, sudo=False, message=None, disconnect=False,
+ retries=0):
"""Convenience function to ssh/exec/return out & err.
Verifies that return code is zero.
-
- Returns (stdout, stderr).
+ Supports retries, timeout is related to each try separately then. There is
+ sleep(1) before each retry.
+ Disconnect (if enabled) is applied after each try.
+
+ :param node: DUT node.
+ :param cmd: Command to be executed.
+ :param timeout: Timeout value in seconds. Default: 600.
+ :param sudo: Sudo privilege execution flag. Default: False.
+ :param message: Error message in case of failure. Default: None.
+ :param disconnect: Close the opened SSH connection if True.
+ :param retries: How many times to retry on failure.
+ :type node: dict
+ :type cmd: str or OptionString
+ :type timeout: int
+ :type sudo: bool
+ :type message: str
+ :type disconnect: bool
+ :type retries: int
+ :returns: Stdout, Stderr.
+ :rtype: tuple(str, str)
+ :raises RuntimeError: If bash return code is not 0.
"""
- (rc, stdout, stderr) = exec_cmd(node, cmd, timeout=timeout, sudo=sudo)
- assert_equal(rc, 0, 'Command execution failed: "{}"\n{}'.
- format(cmd, stderr))
+ for _ in range(retries + 1):
+ ret_code, stdout, stderr = exec_cmd(
+ node, cmd, timeout=timeout, sudo=sudo, disconnect=disconnect)
+ if ret_code == 0:
+ break
+ sleep(1)
+ else:
+ msg = ('Command execution failed: "{cmd}"\n{stderr}'.
+ format(cmd=cmd, stderr=stderr) if message is None else message)
+ raise RuntimeError(msg)
+
return stdout, stderr
+
+def scp_node(
+ node, local_path, remote_path, get=False, timeout=30, disconnect=False):
+ """Copy files from local_path to remote_path or vice versa.
+
+ :param node: SUT node.
+ :param local_path: Path to local file that should be uploaded; or
+ path where to save remote file.
+ :param remote_path: Remote path where to place uploaded file; or
+ path to remote file which should be downloaded.
+ :param get: scp operation to perform. Default is put.
+ :param timeout: Timeout value in seconds.
+ :param disconnect: Close the opened SSH connection if True.
+ :type node: dict
+ :type local_path: str
+ :type remote_path: str
+ :type get: bool
+ :type timeout: int
+ :type disconnect: bool
+ :raises RuntimeError: If SSH connection failed or SCP transfer failed.
+ """
+ ssh = SSH()
+
+ try:
+ ssh.connect(node)
+ except SSHException:
+ raise RuntimeError('Failed to connect to {host}!'
+ .format(host=node['host']))
+ try:
+ ssh.scp(local_path, remote_path, get, timeout)
+ except SCPException:
+ raise RuntimeError('SCP execution failed on {host}!'
+ .format(host=node['host']))
+ finally:
+ if disconnect:
+ ssh.disconnect()
Code Review / csit.git / blobdiff