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.
14 from paramiko import RSAKey
16 from scp import SCPClient
18 from robot.api import logger
19 from interruptingcow import timeout
20 from robot.utils.asserts import assert_equal, assert_not_equal
22 __all__ = ["exec_cmd", "exec_cmd_no_error"]
29 __MAX_RECV_BUF = 10*1024*1024
30 __existing_connections = {}
35 def _node_hash(self, node):
36 return hash(frozenset([node['host'], node['port']]))
38 def connect(self, node):
39 """Connect to node prior to running exec_command or scp.
41 If there already is a connection to the node, this method reuses it.
43 node_hash = self._node_hash(node)
44 if node_hash in SSH.__existing_connections:
45 self._ssh = SSH.__existing_connections[node_hash]
46 logger.debug('reusing ssh: {0}'.format(self._ssh))
50 if 'priv_key' in node:
51 pkey = RSAKey.from_private_key(
52 StringIO.StringIO(node['priv_key']))
54 self._ssh = paramiko.SSHClient()
55 self._ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())
57 self._ssh.connect(node['host'], username=node['username'],
58 password=node.get('password'), pkey=pkey,
61 SSH.__existing_connections[node_hash] = self._ssh
63 logger.trace('connect took {} seconds'.format(time() - start))
64 logger.debug('new ssh: {0}'.format(self._ssh))
66 logger.debug('Connect peer: {0}'.
67 format(self._ssh.get_transport().getpeername()))
68 logger.debug('Connections: {0}'.format(str(SSH.__existing_connections)))
70 def disconnect(self, node):
71 """Close SSH connection to the node.
73 :param node: The node to disconnect from.
76 node_hash = self._node_hash(node)
77 if node_hash in SSH.__existing_connections:
78 ssh = SSH.__existing_connections.pop(node_hash)
81 def exec_command(self, cmd, timeout=10):
82 """Execute SSH command on a new channel on the connected Node.
84 Returns (return_code, stdout, stderr).
86 logger.trace('exec_command on {0}: {1}'
87 .format(self._ssh.get_transport().getpeername(), cmd))
89 chan = self._ssh.get_transport().open_session()
90 if timeout is not None:
91 chan.settimeout(int(timeout))
92 chan.exec_command(cmd)
94 logger.trace('exec_command on {0} took {1} seconds'.format(
95 self._ssh.get_transport().getpeername(), end-start))
99 buf = chan.recv(self.__MAX_RECV_BUF)
106 buf = chan.recv_stderr(self.__MAX_RECV_BUF)
111 return_code = chan.recv_exit_status()
112 logger.trace('chan_recv/_stderr took {} seconds'.format(time()-end))
114 logger.trace('return RC {}'.format(return_code))
115 logger.trace('return STDOUT {}'.format(stdout))
116 logger.trace('return STDERR {}'.format(stderr))
117 return return_code, stdout, stderr
119 def exec_command_sudo(self, cmd, cmd_input=None, timeout=10):
120 """Execute SSH command with sudo on a new channel on the connected Node.
122 :param cmd: Command to be executed.
123 :param cmd_input: Input redirected to the command.
124 :param timeout: Timeout.
125 :return: return_code, stdout, stderr
129 >>> from ssh import SSH
131 >>> ssh.connect(node)
132 >>> #Execute command without input (sudo -S cmd)
133 >>> ssh.exec_command_sudo("ifconfig eth0 down")
134 >>> #Execute command with input (sudo -S cmd <<< "input")
135 >>> ssh.exec_command_sudo("vpp_api_test", "dump_interface_table")
137 if cmd_input is None:
138 command = 'sudo -S {c}'.format(c=cmd)
140 command = 'sudo -S {c} <<< "{i}"'.format(c=cmd, i=cmd_input)
141 return self.exec_command(command, timeout)
143 def interactive_terminal_open(self, time_out=10):
144 """Open interactive terminal on a new channel on the connected Node.
146 :param time_out: Timeout in seconds.
147 :return: SSH channel with opened terminal.
149 .. warning:: Interruptingcow is used here, and it uses
150 signal(SIGALRM) to let the operating system interrupt program
151 execution. This has the following limitations: Python signal
152 handlers only apply to the main thread, so you cannot use this
153 from other threads. You must not use this in a program that
154 uses SIGALRM itself (this includes certain profilers)
156 chan = self._ssh.get_transport().open_session()
159 chan.settimeout(int(time_out))
163 with timeout(time_out, exception=RuntimeError):
164 while not buf.endswith(':~$ '):
165 if chan.recv_ready():
166 buf = chan.recv(4096)
168 raise Exception('Open interactive terminal timeout.')
171 def interactive_terminal_exec_command(self, chan, cmd, prompt,
173 """Execute command on interactive terminal.
175 interactive_terminal_open() method has to be called first!
177 :param chan: SSH channel with opened terminal.
178 :param cmd: Command to be executed.
179 :param prompt: Command prompt, sequence of characters used to
180 indicate readiness to accept commands.
181 :param time_out: Timeout in seconds.
182 :return: Command output.
184 .. warning:: Interruptingcow is used here, and it uses
185 signal(SIGALRM) to let the operating system interrupt program
186 execution. This has the following limitations: Python signal
187 handlers only apply to the main thread, so you cannot use this
188 from other threads. You must not use this in a program that
189 uses SIGALRM itself (this includes certain profilers)
191 chan.sendall('{c}\n'.format(c=cmd))
194 with timeout(time_out, exception=RuntimeError):
195 while not buf.endswith(prompt):
196 if chan.recv_ready():
197 buf += chan.recv(4096)
199 raise Exception("Exec '{c}' timeout.".format(c=cmd))
200 tmp = buf.replace(cmd.replace('\n', ''), '')
201 return tmp.replace(prompt, '')
203 def interactive_terminal_close(self, chan):
204 """Close interactive terminal SSH channel.
206 :param: chan: SSH channel to be closed.
210 def scp(self, local_path, remote_path):
211 """Copy files from local_path to remote_path.
213 connect() method has to be called first!
215 logger.trace('SCP {0} to {1}:{2}'.format(
216 local_path, self._ssh.get_transport().getpeername(), remote_path))
217 # SCPCLient takes a paramiko transport as its only argument
218 scp = SCPClient(self._ssh.get_transport())
220 scp.put(local_path, remote_path)
223 logger.trace('SCP took {0} seconds'.format(end-start))
226 def exec_cmd(node, cmd, timeout=None, sudo=False):
227 """Convenience function to ssh/exec/return rc, out & err.
229 Returns (rc, stdout, stderr).
232 raise TypeError('Node parameter is None')
234 raise TypeError('Command parameter is None')
236 raise ValueError('Empty command parameter')
242 logger.error("Failed to connect to node" + e)
247 (ret_code, stdout, stderr) = ssh.exec_command(cmd, timeout=timeout)
249 (ret_code, stdout, stderr) = ssh.exec_command_sudo(cmd,
255 return (ret_code, stdout, stderr)
257 def exec_cmd_no_error(node, cmd, timeout=None, sudo=False):
258 """Convenience function to ssh/exec/return out & err.
259 Verifies that return code is zero.
261 Returns (stdout, stderr).
263 (rc, stdout, stderr) = exec_cmd(node, cmd, timeout=timeout, sudo=sudo)
264 assert_equal(rc, 0, 'Command execution failed: "{}"\n{}'.
266 return (stdout, stderr)