X-Git-Url: https://gerrit.fd.io/r/gitweb?a=blobdiff_plain;f=resources%2Flibraries%2Fpython%2Fssh.py;h=287ad31d657525b204cf6aab2dc83bd44cc055fd;hb=80e71dac74145241aef844491ebf21cc486d4a23;hp=67193c11e2ca8e9082089d2535d8fdde4f48bd38;hpb=8c12ff59f1a5e750151f5eb0e806dcc80e91c3c2;p=csit.git diff --git a/resources/libraries/python/ssh.py b/resources/libraries/python/ssh.py index 67193c11e2..287ad31d65 100644 --- a/resources/libraries/python/ssh.py +++ b/resources/libraries/python/ssh.py @@ -11,14 +11,17 @@ # See the License for the specific language governing permissions and # limitations under the License. +"""Library for SSH connection management.""" + import StringIO -from time import time +from time import time, sleep import socket import paramiko from paramiko import RSAKey +from paramiko.ssh_exception import SSHException from scp import SCPClient -from interruptingcow import timeout +from interruptingcow import timeout as icTimeout from robot.api import logger from robot.utils.asserts import assert_equal @@ -28,15 +31,25 @@ __all__ = ["exec_cmd", "exec_cmd_no_error"] 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 + :return: IP address and port for the specified node. + :rtype: int + """ + return hash(frozenset([node['host'], node['port']])) def connect(self, node): @@ -44,6 +57,7 @@ class SSH(object): If there already is a connection to the node, this method reuses it. """ + self._node = node node_hash = self._node_hash(node) if node_hash in SSH.__existing_connections: self._ssh = SSH.__existing_connections[node_hash] @@ -53,7 +67,7 @@ class SSH(object): pkey = None if 'priv_key' in node: pkey = RSAKey.from_private_key( - StringIO.StringIO(node['priv_key'])) + StringIO.StringIO(node['priv_key'])) self._ssh = paramiko.SSHClient() self._ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy()) @@ -62,6 +76,8 @@ class SSH(object): password=node.get('password'), pkey=pkey, port=node['port']) + self._ssh.get_transport().set_keepalive(10) + SSH.__existing_connections[node_hash] = self._ssh logger.trace('connect took {} seconds'.format(time() - start)) @@ -79,53 +95,84 @@ class SSH(object): """ node_hash = self._node_hash(node) if node_hash in SSH.__existing_connections: + logger.debug('Disconnecting peer: {}, {}'. + format(node['host'], node['port'])) ssh = SSH.__existing_connections.pop(node_hash) ssh.close() + def _reconnect(self): + """Close the SSH connection and open it again.""" + + node = self._node + self.disconnect(node) + self.connect(node) + logger.debug('Reconnecting peer done: {}'. + format(self._ssh.get_transport().getpeername())) + def exec_command(self, cmd, timeout=10): """Execute SSH command on a new channel on the connected Node. - Returns (return_code, stdout, stderr). + :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. + :type cmd: str + :type timeout: int + :return return_code, stdout, stderr + :rtype: tuple(int, str, str) + :raise socket.timeout: If command is not finished in timeout time. """ + start = time() + stdout = StringIO.StringIO() + stderr = StringIO.StringIO() + try: + chan = self._ssh.get_transport().open_session(timeout=5) + except AttributeError: + self._reconnect() + chan = self._ssh.get_transport().open_session(timeout=5) + except SSHException: + self._reconnect() + chan = self._ssh.get_transport().open_session(timeout=5) + chan.settimeout(timeout) 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) + 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 socket.timeout( + 'Timeout exception.\n' + 'Current contents of stdout buffer: {0}\n' + 'Current contents of stderr buffer: {1}\n' + .format(stdout.getvalue(), stderr.getvalue()) + ) + + sleep(0.1) + return_code = chan.recv_exit_status() + + 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)) + end = time() logger.trace('exec_command on {0} took {1} seconds'.format( self._ssh.get_transport().getpeername(), end-start)) - stdout = "" - 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 - - 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 + logger.trace('return STDOUT {}'.format(stdout.getvalue())) + logger.trace('return STDERR {}'.format(stderr.getvalue())) + return return_code, stdout.getvalue(), stderr.getvalue() - def exec_command_sudo(self, cmd, cmd_input=None, timeout=10): + def exec_command_sudo(self, cmd, cmd_input=None, timeout=30): """Execute SSH command with sudo on a new channel on the connected Node. :param cmd: Command to be executed. @@ -169,7 +216,7 @@ class SSH(object): buf = '' try: - with timeout(time_out, exception=RuntimeError): + with icTimeout(time_out, exception=RuntimeError): while not buf.endswith(':~$ '): if chan.recv_ready(): buf = chan.recv(4096) @@ -179,7 +226,7 @@ class SSH(object): @staticmethod def interactive_terminal_exec_command(chan, cmd, prompt, - time_out=10): + time_out=30): """Execute command on interactive terminal. interactive_terminal_open() method has to be called first! @@ -201,7 +248,7 @@ class SSH(object): chan.sendall('{c}\n'.format(c=cmd)) buf = '' try: - with timeout(time_out, exception=RuntimeError): + with icTimeout(time_out, exception=RuntimeError): while not buf.endswith(prompt): if chan.recv_ready(): buf += chan.recv(4096) @@ -234,7 +281,7 @@ class SSH(object): 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): """Convenience function to ssh/exec/return rc, out & err. Returns (rc, stdout, stderr). @@ -249,9 +296,9 @@ def exec_cmd(node, cmd, timeout=None, sudo=False): ssh = SSH() try: ssh.connect(node) - except Exception, e: - logger.error("Failed to connect to node" + e) - return None + except Exception as err: + logger.error("Failed to connect to node" + str(err)) + return None, None, None try: if not sudo: @@ -259,21 +306,21 @@ def exec_cmd(node, cmd, timeout=None, sudo=False): else: (ret_code, stdout, stderr) = ssh.exec_command_sudo(cmd, timeout=timeout) - except Exception, e: - logger.error(e) - return None + except Exception as err: + logger.error(err) + return None, None, None 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): """Convenience function to ssh/exec/return out & err. Verifies that return code is zero. Returns (stdout, stderr). """ - (rc, stdout, stderr) = exec_cmd(node, cmd, timeout=timeout, sudo=sudo) - assert_equal(rc, 0, 'Command execution failed: "{}"\n{}'. + (ret_code, stdout, stderr) = exec_cmd(node, cmd, timeout=timeout, sudo=sudo) + assert_equal(ret_code, 0, 'Command execution failed: "{}"\n{}'. format(cmd, stderr)) return stdout, stderr