Hi All,
A day back I install Twisted and Conch on RHEL5. I am a novice user of
Twisted software.
I copied an example from dev-shed website (attached herewith). This example
script uses conch to talk to a ssh deamon.
This script was able to capture and return the output of simple commands
such as - ls, cat etc.
I mean, when I run the script to execute 'ls -al' on a remote machine it
does and returns the prompt.
Where as, when I run the script to execute '*tail -f /path/to/mylog.txt*' I
get the ouput of this command but the prompt never returns.
When I press ^C (Control-C) I get the following run-time error.
*Traceback (most recent call last):
File
"/usr/lib/python2.4/site-packages/Twisted-8.2.0-py2.4-linux-i686.egg/twisted/internet/tcp.py",
line 520, in connectionLost
protocol.connectionLost(reason)
File
"/usr/lib/python2.4/site-packages/Twisted-8.2.0-py2.4-linux-i686.egg/twisted/conch/ssh/transport.py",
line 166, in connectionLost
self.service.serviceStopped()
File
"/usr/lib/python2.4/site-packages/Twisted-8.2.0-py2.4-linux-i686.egg/twisted/conch/ssh/connection.py",
line 59, in serviceStopped
map(self.channelClosed, self.channels.values())
File
"/usr/lib/python2.4/site-packages/Twisted-8.2.0-py2.4-linux-i686.egg/twisted/conch/ssh/connection.py",
line 580, in channelClosed
log.callWithLogger(channel, channel.closed)
--- <exception caught here> ---
File
"/usr/lib/python2.4/site-packages/Twisted-8.2.0-py2.4-linux-i686.egg/twisted/python/log.py",
line 84, in callWithLogger
return callWithContext({"system": lp}, func, *args, **kw)
File
"/usr/lib/python2.4/site-packages/Twisted-8.2.0-py2.4-linux-i686.egg/twisted/python/log.py",
line 69, in callWithContext
return context.call({ILogContext: newCtx}, func, *args, **kw)
File
"/usr/lib/python2.4/site-packages/Twisted-8.2.0-py2.4-linux-i686.egg/twisted/python/context.py",
line 59, in callWithContext
return self.currentContext().callWithContext(ctx, func, *args, **kw)
File
"/usr/lib/python2.4/site-packages/Twisted-8.2.0-py2.4-linux-i686.egg/twisted/python/context.py",
line 37, in callWithContext
return func(*args,**kw)
File "shankha.py", line 56, in closed
reactor.stop()
File
"/usr/lib/python2.4/site-packages/Twisted-8.2.0-py2.4-linux-i686.egg/twisted/internet/base.py",
line 526, in stop
raise error.ReactorNotRunning(
twisted.internet.error.ReactorNotRunning: Can't stop reactor that isn't
running.*
*I know that 'tail -f' command is expecting "Control-C" or Break to return
the prompt on remote host.
But my attempt to send the ^C character is failing..
I am doing somethink like this:
python sshc.py <hostname> 'tail -f mylog.txt ; \x03'
What is the recommended method to adopt such cases?
*Cheers!!
Harsha Reddy
from twisted.conch import error
from twisted.conch.ssh import transport, connection, keys, userauth, channel, common
from twisted.internet import defer, protocol, reactor
class ClientCommandTransport(transport.SSHClientTransport):
def __init__(self, username, password, command) :
self.username = username
self.password = password
self.command = command
def verifyHostKey(self, pubKey, fingerprint):
# in a real app, you should verify that the fingerprint matches
# the one you expected to get from this server
return defer.succeed(True)
def connectionSecure(self):
self.requestService(
PasswordAuth(self.username, self.password,
ClientConnection(self.command)))
class PasswordAuth(userauth.SSHUserAuthClient):
def __init__(self, user, password, connection):
userauth.SSHUserAuthClient.__init__(self, user, connection)
self.password = password
def getPassword(self, prompt=None):
return defer.succeed(self.password)
class ClientConnection(connection.SSHConnection):
def __init__(self, cmd, *args, **kwargs):
connection.SSHConnection.__init__(self)
self.command = cmd
def serviceStarted(self):
self.openChannel(CommandChannel(self.command, conn=self))
class CommandChannel(channel.SSHChannel):
name = 'session'
def __init__(self, command, *args, **kwargs):
channel.SSHChannel.__init__(self, *args, **kwargs)
self.command = command
def channelOpen(self, data):
self.conn.sendRequest(
self, 'exec', common.NS(self.command), wantReply=True).addCallback(
self._gotResponse)
def _gotResponse(self, _):
self.conn.sendEOF(self)
def dataReceived(self, data):
print data
def closed(self):
reactor.stop()
class ClientCommandFactory(protocol.ClientFactory):
def __init__(self, username, password, command):
self.username = username
self.password = password
self.command = command
def buildProtocol(self, addr):
protocol = ClientCommandTransport(
self.username, self.password, self.command)
return protocol
if __name__ == "__main__":
import sys, getpass
server = sys.argv[1]
command = sys.argv[2]
username = raw_input("Username: ")
password = getpass.getpass("Password: ")
factory = ClientCommandFactory(username, password, command)
reactor.connectTCP(server, 22, factory)
reactor.run() _______________________________________________
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