1 # Copyright (c) 2016 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.
15 from time import time, sleep
19 from paramiko import RSAKey
20 from paramiko.ssh_exception import SSHException
21 from scp import SCPClient
22 from interruptingcow import timeout
23 from robot.api import logger
24 from robot.utils.asserts import assert_equal
26 __all__ = ["exec_cmd", "exec_cmd_no_error"]
33 __MAX_RECV_BUF = 10*1024*1024
34 __existing_connections = {}
42 return hash(frozenset([node['host'], node['port']]))
44 def connect(self, node):
45 """Connect to node prior to running exec_command or scp.
47 If there already is a connection to the node, this method reuses it.
50 node_hash = self._node_hash(node)
51 if node_hash in SSH.__existing_connections:
52 self._ssh = SSH.__existing_connections[node_hash]
53 logger.debug('reusing ssh: {0}'.format(self._ssh))
57 if 'priv_key' in node:
58 pkey = RSAKey.from_private_key(
59 StringIO.StringIO(node['priv_key']))
61 self._ssh = paramiko.SSHClient()
62 self._ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())
64 self._ssh.connect(node['host'], username=node['username'],
65 password=node.get('password'), pkey=pkey,
68 SSH.__existing_connections[node_hash] = self._ssh
70 logger.trace('connect took {} seconds'.format(time() - start))
71 logger.debug('new ssh: {0}'.format(self._ssh))
73 logger.debug('Connect peer: {0}'.
74 format(self._ssh.get_transport().getpeername()))
75 logger.debug('Connections: {0}'.format(str(SSH.__existing_connections)))
77 def disconnect(self, node):
78 """Close SSH connection to the node.
80 :param node: The node to disconnect from.
83 node_hash = self._node_hash(node)
84 if node_hash in SSH.__existing_connections:
85 logger.debug('Disconnecting peer: {}, {}'.
86 format(node['host'], node['port']))
87 ssh = SSH.__existing_connections.pop(node_hash)
94 logger.debug('Reconnecting peer done: {}'.
95 format(self._ssh.get_transport().getpeername()))
97 def exec_command(self, cmd, timeout=10):
98 """Execute SSH command on a new channel on the connected Node.
100 :param cmd: Command to run on the Node.
101 :param timeout: Maximal time in seconds to wait while the command is
102 done. If is None then wait forever.
105 :return return_code, stdout, stderr
106 :rtype: tuple(int, str, str)
107 :raise socket.timeout: If command is not finished in timeout time.
110 stdout = StringIO.StringIO()
111 stderr = StringIO.StringIO()
113 chan = self._ssh.get_transport().open_session(timeout=5)
114 except AttributeError:
116 chan = self._ssh.get_transport().open_session(timeout=5)
119 chan = self._ssh.get_transport().open_session(timeout=5)
120 chan.settimeout(timeout)
121 logger.trace('exec_command on {0}: {1}'
122 .format(self._ssh.get_transport().getpeername(), cmd))
124 chan.exec_command(cmd)
125 while not chan.exit_status_ready() and timeout is not None:
126 if chan.recv_ready():
127 stdout.write(chan.recv(self.__MAX_RECV_BUF))
129 if chan.recv_stderr_ready():
130 stderr.write(chan.recv_stderr(self.__MAX_RECV_BUF))
132 if time() - start > timeout:
133 raise socket.timeout(
134 'Timeout exception.\n'
135 'Current contents of stdout buffer: {0}\n'
136 'Current contents of stderr buffer: {1}\n'
137 .format(stdout.getvalue(), stderr.getvalue())
141 return_code = chan.recv_exit_status()
143 while chan.recv_ready():
144 stdout.write(chan.recv(self.__MAX_RECV_BUF))
146 while chan.recv_stderr_ready():
147 stderr.write(chan.recv_stderr(self.__MAX_RECV_BUF))
150 logger.trace('exec_command on {0} took {1} seconds'.format(
151 self._ssh.get_transport().getpeername(), end-start))
153 logger.trace('chan_recv/_stderr took {} seconds'.format(time()-end))
155 logger.trace('return RC {}'.format(return_code))
156 logger.trace('return STDOUT {}'.format(stdout.getvalue()))
157 logger.trace('return STDERR {}'.format(stderr.getvalue()))
158 return return_code, stdout.getvalue(), stderr.getvalue()
160 def exec_command_sudo(self, cmd, cmd_input=None, timeout=30):
161 """Execute SSH command with sudo on a new channel on the connected Node.
163 :param cmd: Command to be executed.
164 :param cmd_input: Input redirected to the command.
165 :param timeout: Timeout.
166 :return: return_code, stdout, stderr
170 >>> from ssh import SSH
172 >>> ssh.connect(node)
173 >>> # Execute command without input (sudo -S cmd)
174 >>> ssh.exec_command_sudo("ifconfig eth0 down")
175 >>> # Execute command with input (sudo -S cmd <<< "input")
176 >>> ssh.exec_command_sudo("vpp_api_test", "dump_interface_table")
178 if cmd_input is None:
179 command = 'sudo -S {c}'.format(c=cmd)
181 command = 'sudo -S {c} <<< "{i}"'.format(c=cmd, i=cmd_input)
182 return self.exec_command(command, timeout)
184 def interactive_terminal_open(self, time_out=10):
185 """Open interactive terminal on a new channel on the connected Node.
187 :param time_out: Timeout in seconds.
188 :return: SSH channel with opened terminal.
190 .. warning:: Interruptingcow is used here, and it uses
191 signal(SIGALRM) to let the operating system interrupt program
192 execution. This has the following limitations: Python signal
193 handlers only apply to the main thread, so you cannot use this
194 from other threads. You must not use this in a program that
195 uses SIGALRM itself (this includes certain profilers)
197 chan = self._ssh.get_transport().open_session()
200 chan.settimeout(int(time_out))
204 with timeout(time_out, exception=RuntimeError):
205 while not buf.endswith(':~$ '):
206 if chan.recv_ready():
207 buf = chan.recv(4096)
209 raise Exception('Open interactive terminal timeout.')
213 def interactive_terminal_exec_command(chan, cmd, prompt,
215 """Execute command on interactive terminal.
217 interactive_terminal_open() method has to be called first!
219 :param chan: SSH channel with opened terminal.
220 :param cmd: Command to be executed.
221 :param prompt: Command prompt, sequence of characters used to
222 indicate readiness to accept commands.
223 :param time_out: Timeout in seconds.
224 :return: Command output.
226 .. warning:: Interruptingcow is used here, and it uses
227 signal(SIGALRM) to let the operating system interrupt program
228 execution. This has the following limitations: Python signal
229 handlers only apply to the main thread, so you cannot use this
230 from other threads. You must not use this in a program that
231 uses SIGALRM itself (this includes certain profilers)
233 chan.sendall('{c}\n'.format(c=cmd))
236 with timeout(time_out, exception=RuntimeError):
237 while not buf.endswith(prompt):
238 if chan.recv_ready():
239 buf += chan.recv(4096)
241 raise Exception("Exec '{c}' timeout.".format(c=cmd))
242 tmp = buf.replace(cmd.replace('\n', ''), '')
243 return tmp.replace(prompt, '')
246 def interactive_terminal_close(chan):
247 """Close interactive terminal SSH channel.
249 :param: chan: SSH channel to be closed.
253 def scp(self, local_path, remote_path):
254 """Copy files from local_path to remote_path.
256 connect() method has to be called first!
258 logger.trace('SCP {0} to {1}:{2}'.format(
259 local_path, self._ssh.get_transport().getpeername(), remote_path))
260 # SCPCLient takes a paramiko transport as its only argument
261 scp = SCPClient(self._ssh.get_transport())
263 scp.put(local_path, remote_path)
266 logger.trace('SCP took {0} seconds'.format(end-start))
269 def exec_cmd(node, cmd, timeout=600, sudo=False):
270 """Convenience function to ssh/exec/return rc, out & err.
272 Returns (rc, stdout, stderr).
275 raise TypeError('Node parameter is None')
277 raise TypeError('Command parameter is None')
279 raise ValueError('Empty command parameter')
285 logger.error("Failed to connect to node" + str(e))
286 return None, None, None
290 (ret_code, stdout, stderr) = ssh.exec_command(cmd, timeout=timeout)
292 (ret_code, stdout, stderr) = ssh.exec_command_sudo(cmd,
296 return None, None, None
298 return ret_code, stdout, stderr
301 def exec_cmd_no_error(node, cmd, timeout=600, sudo=False):
302 """Convenience function to ssh/exec/return out & err.
304 Verifies that return code is zero.
306 Returns (stdout, stderr).
308 (rc, stdout, stderr) = exec_cmd(node, cmd, timeout=timeout, sudo=sudo)
309 assert_equal(rc, 0, 'Command execution failed: "{}"\n{}'.
311 return stdout, stderr