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.
19 from paramiko import RSAKey
20 from scp import SCPClient
21 from interruptingcow import timeout
22 from robot.api import logger
23 from robot.utils.asserts import assert_equal
25 __all__ = ["exec_cmd", "exec_cmd_no_error"]
32 __MAX_RECV_BUF = 10*1024*1024
33 __existing_connections = {}
40 return hash(frozenset([node['host'], node['port']]))
42 def connect(self, node):
43 """Connect to node prior to running exec_command or scp.
45 If there already is a connection to the node, this method reuses it.
47 node_hash = self._node_hash(node)
48 if node_hash in SSH.__existing_connections:
49 self._ssh = SSH.__existing_connections[node_hash]
50 logger.debug('reusing ssh: {0}'.format(self._ssh))
54 if 'priv_key' in node:
55 pkey = RSAKey.from_private_key(
56 StringIO.StringIO(node['priv_key']))
58 self._ssh = paramiko.SSHClient()
59 self._ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())
61 self._ssh.connect(node['host'], username=node['username'],
62 password=node.get('password'), pkey=pkey,
65 SSH.__existing_connections[node_hash] = self._ssh
67 logger.trace('connect took {} seconds'.format(time() - start))
68 logger.debug('new ssh: {0}'.format(self._ssh))
70 logger.debug('Connect peer: {0}'.
71 format(self._ssh.get_transport().getpeername()))
72 logger.debug('Connections: {0}'.format(str(SSH.__existing_connections)))
74 def disconnect(self, node):
75 """Close SSH connection to the node.
77 :param node: The node to disconnect from.
80 node_hash = self._node_hash(node)
81 if node_hash in SSH.__existing_connections:
82 ssh = SSH.__existing_connections.pop(node_hash)
85 def exec_command(self, cmd, timeout=10):
86 """Execute SSH command on a new channel on the connected Node.
88 Returns (return_code, stdout, stderr).
90 logger.trace('exec_command on {0}: {1}'
91 .format(self._ssh.get_transport().getpeername(), cmd))
93 chan = self._ssh.get_transport().open_session()
94 if timeout is not None:
95 chan.settimeout(int(timeout))
96 chan.exec_command(cmd)
98 logger.trace('exec_command on {0} took {1} seconds'.format(
99 self._ssh.get_transport().getpeername(), end-start))
104 buf = chan.recv(self.__MAX_RECV_BUF)
108 except socket.timeout:
109 logger.error('Caught timeout exception, current contents '
110 'of buffer: {0}'.format(stdout))
115 buf = chan.recv_stderr(self.__MAX_RECV_BUF)
120 return_code = chan.recv_exit_status()
121 logger.trace('chan_recv/_stderr took {} seconds'.format(time()-end))
123 logger.trace('return RC {}'.format(return_code))
124 logger.trace('return STDOUT {}'.format(stdout))
125 logger.trace('return STDERR {}'.format(stderr))
126 return return_code, stdout, stderr
128 def exec_command_sudo(self, cmd, cmd_input=None, timeout=10):
129 """Execute SSH command with sudo on a new channel on the connected Node.
131 :param cmd: Command to be executed.
132 :param cmd_input: Input redirected to the command.
133 :param timeout: Timeout.
134 :return: return_code, stdout, stderr
138 >>> from ssh import SSH
140 >>> ssh.connect(node)
141 >>> # Execute command without input (sudo -S cmd)
142 >>> ssh.exec_command_sudo("ifconfig eth0 down")
143 >>> # Execute command with input (sudo -S cmd <<< "input")
144 >>> ssh.exec_command_sudo("vpp_api_test", "dump_interface_table")
146 if cmd_input is None:
147 command = 'sudo -S {c}'.format(c=cmd)
149 command = 'sudo -S {c} <<< "{i}"'.format(c=cmd, i=cmd_input)
150 return self.exec_command(command, timeout)
152 def interactive_terminal_open(self, time_out=10):
153 """Open interactive terminal on a new channel on the connected Node.
155 :param time_out: Timeout in seconds.
156 :return: SSH channel with opened terminal.
158 .. warning:: Interruptingcow is used here, and it uses
159 signal(SIGALRM) to let the operating system interrupt program
160 execution. This has the following limitations: Python signal
161 handlers only apply to the main thread, so you cannot use this
162 from other threads. You must not use this in a program that
163 uses SIGALRM itself (this includes certain profilers)
165 chan = self._ssh.get_transport().open_session()
168 chan.settimeout(int(time_out))
172 with timeout(time_out, exception=RuntimeError):
173 while not buf.endswith(':~$ '):
174 if chan.recv_ready():
175 buf = chan.recv(4096)
177 raise Exception('Open interactive terminal timeout.')
181 def interactive_terminal_exec_command(chan, cmd, prompt,
183 """Execute command on interactive terminal.
185 interactive_terminal_open() method has to be called first!
187 :param chan: SSH channel with opened terminal.
188 :param cmd: Command to be executed.
189 :param prompt: Command prompt, sequence of characters used to
190 indicate readiness to accept commands.
191 :param time_out: Timeout in seconds.
192 :return: Command output.
194 .. warning:: Interruptingcow is used here, and it uses
195 signal(SIGALRM) to let the operating system interrupt program
196 execution. This has the following limitations: Python signal
197 handlers only apply to the main thread, so you cannot use this
198 from other threads. You must not use this in a program that
199 uses SIGALRM itself (this includes certain profilers)
201 chan.sendall('{c}\n'.format(c=cmd))
204 with timeout(time_out, exception=RuntimeError):
205 while not buf.endswith(prompt):
206 if chan.recv_ready():
207 buf += chan.recv(4096)
209 raise Exception("Exec '{c}' timeout.".format(c=cmd))
210 tmp = buf.replace(cmd.replace('\n', ''), '')
211 return tmp.replace(prompt, '')
214 def interactive_terminal_close(chan):
215 """Close interactive terminal SSH channel.
217 :param: chan: SSH channel to be closed.
221 def scp(self, local_path, remote_path):
222 """Copy files from local_path to remote_path.
224 connect() method has to be called first!
226 logger.trace('SCP {0} to {1}:{2}'.format(
227 local_path, self._ssh.get_transport().getpeername(), remote_path))
228 # SCPCLient takes a paramiko transport as its only argument
229 scp = SCPClient(self._ssh.get_transport())
231 scp.put(local_path, remote_path)
234 logger.trace('SCP took {0} seconds'.format(end-start))
237 def exec_cmd(node, cmd, timeout=None, sudo=False):
238 """Convenience function to ssh/exec/return rc, out & err.
240 Returns (rc, stdout, stderr).
243 raise TypeError('Node parameter is None')
245 raise TypeError('Command parameter is None')
247 raise ValueError('Empty command parameter')
253 logger.error("Failed to connect to node" + str(e))
258 (ret_code, stdout, stderr) = ssh.exec_command(cmd, timeout=timeout)
260 (ret_code, stdout, stderr) = ssh.exec_command_sudo(cmd,
266 return ret_code, stdout, stderr
269 def exec_cmd_no_error(node, cmd, timeout=None, sudo=False):
270 """Convenience function to ssh/exec/return out & err.
272 Verifies that return code is zero.
274 Returns (stdout, stderr).
276 (rc, stdout, stderr) = exec_cmd(node, cmd, timeout=timeout, sudo=sudo)
277 assert_equal(rc, 0, 'Command execution failed: "{}"\n{}'.
279 return stdout, stderr