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Diffstat (limited to 'Monitoring/MonitoringService/Driver/SshExec.py')
| -rw-r--r-- | Monitoring/MonitoringService/Driver/SshExec.py | 170 |
1 files changed, 170 insertions, 0 deletions
diff --git a/Monitoring/MonitoringService/Driver/SshExec.py b/Monitoring/MonitoringService/Driver/SshExec.py new file mode 100644 index 0000000..454253c --- /dev/null +++ b/Monitoring/MonitoringService/Driver/SshExec.py @@ -0,0 +1,170 @@ +''' +Created on Jul 18, 2011 + +@author: steger, jozsef +@organization: ELTE +@contact: steger@complex.elte.hu +''' + +from Driver import Driver, DriverError +from paramiko import SSHClient, RSAKey, SSHException, AutoAddPolicy +from Credential.credentialtypes import UsernamePassword, UsernameRSAKey +from time import sleep +import socket +import logging + +class SshDriver(Driver): + ''' + @summary: implements a driver to build an SSH connection to a server using paramiko package. + @cvar timeout: a timeout to set up the connection + @type timeout: float + @cvar trials: how many times to retry if a time out event occurs or if the remote server is busy to respond + @type trials: int + @cvar wait: how long to wait between two trials + @type wait: .2 + @ivar client: the api of the ssh client + @type client: paramiko.SSHClient or None + @ivar host: the host name of the remote ssh server + @type host: str or None + @ivar isconnected: indicates whether the connection is set up + @type isconnected: bool + ''' + timeout = 5 + trials = 3 + wait = .2 + + def __init__(self): + ''' + @summary: bind the paramiko loggers to the "NOVI.DRIVER" + ''' + self.client = None + self.host = None + #bind paramiko.transport logger to the same handlers used by NOVI.DRIVER + l = logging.getLogger("paramiko.transport") + for hlr in self.logger.handlers: + l.addHandler(hlr) + + def __del__(self): + ''' + @summary: close connection upon an implicit deletion of the driver + ''' + self.close() + + def connect(self, host, credential, port = 22, known_host = None): + ''' + @summary: set up the connection + @param host: the host name of the remote server + @type host: str + @param credential: the secret to use for connection set up + @type credential: L{Credential} + @param port: the port remote ssh server is listening + @type port: int + @param known_host: a file name containing host signatures to check, if None AutoAddPolicy applies + @type known_host: str + ''' + self.client = SSHClient() + if known_host is None: + self.client.set_missing_host_key_policy( AutoAddPolicy() ) + else: + self.client.load_host_keys(filename = known_host) + if isinstance(credential, UsernamePassword): + # use password authentication + self.client.connect(hostname = host, port = port, + username = credential.username, password =credential.password, + timeout = self.timeout, look_for_keys = False, compress = True) + elif isinstance(credential, UsernameRSAKey): + # use the RSA key + if credential.password: + pw = credential.password + else: + pw = None + key = RSAKey(password = pw, filename = credential.rsakey) + n = self.trials + while n: + try: + self.client.connect(hostname = host, port = port, + username = credential.username, pkey = key, + timeout = self.timeout, look_for_keys = False, compress = True) + break + except SSHException, e: + if e.message.startswith("Error reading SSH protocol banner"): + n -= 1 + self.logger.warn("retry %d times to connect @%s in %f seconds" % (n, host, self.wait)) + sleep(self.wait) + else: + self.logger.error("cannot connect @%s" % (host)) + raise DriverError("Cannot connect @%s " % host) + except socket.timeout: + n -= 1 + self.logger.warn("time out, retry %d times to connect @%s in %f seconds" % (n, host, self.wait)) + sleep(self.wait) + if not self.isConnected: + self.close() + self.logger.error("cannot connect @%s" % (host)) + raise DriverError("Cannot connect @%s " % host) + self.host = host + self.logger.info("ssh connected @ %s:%d" % (self.host, port)) + + def close(self): + ''' + @summary: closes the ssh connection + ''' + try: + self.client.close() + self.logger.info("ssh disconnected @ %s" % (self.host)) + except: + pass + finally: + self.client = None + self.host = None + + @property + def isConnected(self): + try: + return self.client.get_transport().is_active() + except: + return False + +class SshExec(SshDriver): + ''' + @summary: an extension of the L{SshDriver} to execute commands on the remote machine + @ivar command: the string representation of the command to run + @type command: str + ''' + + def __init__(self, host, credential, port = 22, command = "echo helloworld @ `hostname`", known_host = None): + ''' + @summary: initializes an ssh connection and stores a default command + @param host: the host name of the remote server + @type host: str + @param credential: the secret to use for connection set up + @type credential: L{Credential} + @param port: the port remote ssh server is listening + @type port: int + @param command: the default remote command + @type command: str + @param known_host: a file name containing host signatures to check, if None AutoAddPolicy applies + @type known_host: str + ''' + SshDriver.__init__(self) + self.connect(host, credential, port, known_host) + self.command = command + + def execute(self, command = None): + ''' + @summary: executes a remote command + @param command: the command to run, if None, the default command is issued + @type command: str or None + @return: the standard output of the command run + @rtype: paramico.ChannelFile + ''' + if not self.isConnected: + raise DriverError("Not connected") + if command is None: + command = self.command + _, stout, sterr = self.client.exec_command(command = command) + e = sterr.read() + self.logger.debug("executed @%s '%s'" % (self.host, command)) + if len(e): + self.logger.warning("execution @%s '%s' failed: %s" % (self.host, command, e)) + return stout |