🌐 Mailman 3 October 2008 - Python-list - python.org

Re: renice
by Dan July 14, 2009

July 14, 2009

On Oct 26, 4:30 am, mokhtar <mbmessa...(a)yahoo.com> wrote: > Hi > > Is it possible to renice the python process executing the current python > script ?:confused: > -- > View this message in context:http://www.nabble.com/renice-tf4695834.html#a13422771 > Sent from the Python - python-list mailing list archive at Nabble.com. On UNIX: >>> import os >>> os.system("renice -n %d %d" % ( new_nice, os.getpid() ) ) (untested) I don't know if windows has the concept of renice... -Dan

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Re: SSH utility
by Sean DiZazzo July 8, 2009

July 8, 2009

On Aug 11, 5:17 am, Edwin.Mad...(a)VerizonWireless.com wrote: > for similar tasks, I use pexpecthttp://pypi.python.org/pypi/pexpect. > > spawning bash process and simulate an interactive session. Here sending ls command, retrieving results and exiting. In the spawned process ssh or any other command, is just another command. > > ------------actual session-------------------------- > $ python > Python 2.5.1 (r251:54863, May 18 2007, 16:56:43) > [GCC 3.4.4 (cygming special, gdc 0.12, using dmd 0.125)] on cygwin > Type "help", "copyright", "credits" or "license" for more information.>>> import pexpect > >>> c = pexpect.spawn('/bin/bash') > >>> c.expect([pexpect.TIMEOUT, pexpect.EOF, '\$ ']) > 2 > >>> c.before, c.after > > ('\x1b[?1034hmadared@NJWARHQD0IT696A:~\r\n', '$ ')>>> c.sendline('ls') > 3 > >>> c.expect([pexpect.TIMEOUT, pexpect.EOF, '\$ ']) > 2 > >>> c.before, c.after > > ('ls\r\x.txt xx.txt xy.txt y.txt\r\nmadared@NJWARHQD0IT696A:~\r\n', '$ ')>>> c.sendline('exit') > 5 > >>> c.expect([pexpect.TIMEOUT, pexpect.EOF, '\$ ']) > 1 > >>> c.before, c.after > > ('exit\r\nexit\r\n', <class 'pexpect.EOF'>)>>> exit() > > madared@NJWARHQD0IT696A:~ > $ > --------------------------------------------------------------- > > hope that helps. > > regards. > Edwin > > -----Original Message----- > From: python-list-bounces+edwin.madari=verizonwireless....(a)python.org > > [mailto:python-list-bounces+edwin.madari=verizonwireless....@python.org] > On Behalf Of James Brady > Sent: Monday, August 11, 2008 12:26 AM > To: python-l...(a)python.org > Subject: SSH utility > > Hi all, > I'm looking for a python library that lets me execute shell commands > on remote machines. > > I've tried a few SSH utilities so far: paramiko, PySSH and pssh; > unfortunately all been unreliable, and repeated questions on their > respective mailing lists haven't been answered... > > It seems like the sort of commodity task that there should be a pretty > robust library for. Are there any suggestions for alternative > libraries or approaches? > > Thanks! > James > --http://mail.python.org/mailman/listinfo/python-list > > The information contained in this message and any attachment may be > proprietary, confidential, and privileged or subject to the work > product doctrine and thus protected from disclosure. If the reader > of this message is not the intended recipient, or an employee or > agent responsible for delivering this message to the intended > recipient, you are hereby notified that any dissemination, > distribution or copying of this communication is strictly prohibited. > If you have received this communication in error, please notify me > immediately by replying to this message and deleting it and all > copies and backups thereof. Thank you. I second pexpect and the nice little module that comes with it ssh_session.py. Been using it for ages now! ~Sean

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Problems running on hp dual core processor
by jim-on-linux April 16, 2009

April 16, 2009

Python help, I have a number of clients running a program built with python 2.5. One has just purchased an HP with a duel core processor, 2.2G with .099g ram. On the new hp, when they try to print they get an import error; File win32ui.pyc line 12, in <module> File win32ui.pyc, line 10, in _load ImportError: DLL load failed: The specified module could not be found. The file is there The only difference I could find from their other machines is the processor.

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Unable to abort a FTP command?
by _wdx＠163.com April 15, 2009

April 15, 2009

Hi, I write the following script to retrieve a part of a large file from a FTP site: import ftplib class ftp_getter(object): def __init__(self): self.handle = ftplib.FTP('ftp_server_address') self.handle.set_debuglevel(2) self.login() def login(self): self.handle.login('user', 'pass') self.handle.cwd('/temp1/') def quit(self, is_close = False): self.handle.quit() if is_close: self.handle.close() print 'ftp handle closed' def getpart_callback(self, received): print "received a packet" if self.cnt <= 0: if not self.outf.closed: self.outf.close() if not self.aborted: try: self.handle.abort() self.aborted = True except Exception,ex: pass else: print 'received packet, [0] = %x' % ord(received[0]) self.outf.write(received) self.cnt -= len(received) def getpart(self, ftp_filename, rest, cnt, out_filename): self.outf = open(out_filename, 'wb') self.cnt = cnt self.aborted = False self.handle.retrbinary('RETR ' + ftp_filename, self.getpart_callback, 8192, rest) if not self.outf.closed: self.outf.close() if __name__ == '__main__': g = ftp_getter() g.getpart('FILE_TO_RETRIEVE.DAT', 50000, 20, 'out.dat') g.quit(True) print "all done." As the last four lines shown, I want to connect to my FTP server, retrieve 20 bytes starting at offset 50000 from FILE_TO_RETRIEVE.DAT, and stop retrieving after more than 20 bytes have been received. It's quite simple, but to my suprise, this code does not work. "self.handle.abort()" have been executed and I got the expected response from server(426), but the RETR command does not seem to stop at all. More and more data are received and getpart_callback method is called again and again. Why the RETR command is not actually aborted? Can anyone help me? Thanks Xu Wang

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Writing a well-behaved daemon
by Ben Finney March 25, 2009

March 25, 2009

Howdy all, Writing a Python program to become a Unix daemon is relatively well-documented: there's a recipe for detaching the process and running in its own process group. However, there's much more to a Unix daemon than simply detaching. At a minimum, a well-behaved Unix daemon must at least: * Detach the process into its own process group * Close stdin, redirect stdout and stderr to a null device * Handle its own PID file: refuse to start if the PID file already exists, write the PID file on startup otherwise, and remove the PID file on termination * Revoke setuid and setgid privileges, which are strongly deprecated these days * Handle interrupts, cleaning up the process and PID file as necessary * (possible others) There are also many other commonly-expected tasks that well-behaved Unix daemons perform (drop privileges to a nominated non-root user and group after daemonising, redirect output to syslog instead, operate in a chroot jail, respawn when terminated, etc.). All of this stuff has been done numerous times before, and the basics are mostly agreed upon. Yet all of these are tricky to implement correctly, and tedious to re-implement in every program intended to run as a daemon. The 'daemon' program <URL:http://www.libslack.org/daemon/> covers all these, and allows an arbitrary process to be started as a well-behaved Unix daemon process. It's not a good assumption that this program is installed on an arbitrary system though, and it seems excessive to ask the recipient of one's program to get a third-party program just in order to make a daemon process. I'd love to be able to have something similar for Python programs, e.g. a 'become_well_behaved_daemon()' function that implements all the above and perhaps takes optional arguments for the optional features. My searches for such functionality haven't borne much fruit though. Apart from scattered recipes, none of which cover all the essentials (let alone the optional features) of 'daemon', I can't find anything that could be relied upon. This is surprising, since I'd expect this in Python's standard library. Can anyone point me to the equivalent of the 'daemon' program in the form of a well-tested Python library? -- \ “Tis more blessed to give than to receive; for example, wedding | `\ presents.” —Henry L. Mencken | _o__) | Ben Finney

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decorators tutorials
by james_027 March 23, 2009

March 23, 2009

Hi, I am learning python by learning django, and I stumble upon decorator which is very cool, any beginners resources for python decorators, although I can google it, I just want to get a good tutorial for this topic. Thanks james

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Re: Implementaion of random.shuffle
by Hrvoje Niksic Feb. 20, 2009

Feb. 20, 2009

Steve Holden <steve(a)holdenweb.com> writes: > So it would appear that the developers chose the Knuth algorithm > (with a slight variation) for *their* implementation. Now you have > to ask yourself whether your surmise is genuinely correct (in which > case the documentation may contain a bug) or whether the > documentation is indeed correct and you are in error. That is a good question. The random module uses the Mersenne twister, which has a repetition period of 2**19937. The number of n-sized permutations of a list with n elements is n!, while each shuffle requires n calls to the PRNG. This means that to be able to generate all permutations, the PRNG must have a period of at least n! * n. In the case of MT, it means that, regarding the period, you are safe for lists with around 2079 elements. shuffle's documentation may have been written before the random module was converted to use the MT. 2**19937 being a really huge number, it's impossible to exhaust the Mersenne twister by running it in sequence. However, there is also the question of the spread of the first shuffle. Ideally we'd want any shuffle, including the first one, to be able to produce any of the n! permutations. To achieve that, the initial state of the PRNG must be able to support at least n! different outcomes, which means that the PRNG must be seeded by at least log2(n!) bits of randomness from an outside source. For reference, Linux's /dev/random stops blocking when 64 bits of randomness are available from the entropy pool, which means that, in the worst case, shuffling more than 20 elements cannot represent all permutations in the first shuffle!

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is it possible to add a property to an instance?
by Darren Dale Feb. 20, 2009

Feb. 20, 2009

Does anyone know if it is possible to add a property to an instance at runtime? I didn't see anything about it in the standard library's new module, google hasn't turned up much either. Thanks, Darren

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Re: Python is slow?
by Lawrence D'Oliveiro Feb. 15, 2009

Feb. 15, 2009

In message <mailman.1764.1222798473.3487.python-list(a)python.org>, José Matos wrote: > The gnuplot license is a free software according to FSF ... Not listed as one <http://www.fsf.org/licensing/licenses/index_html/view?searchterm=license>.

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PyQt, Cannot send events to objects owned by a different thread?
by Alexander Tuchacek Jan. 18, 2009

Jan. 18, 2009

hallo, i try to adress an qt object self.statusbar.showMessage("rtt %s...." % (n.rtt)) in an callback function, comming from a shared lib importet by ctypes, on osx this works wonderfull when i run the same code on linux (ubuntu gutsy), i get this core dump, ok, i understand that the problem is, that i cant speak to the qt thread, but why does it work on osx? shall i recompile python? pyqt or sip? without threads? could somebody give me a hint what to do best? how can i call a qt object in an c-lib callback? thanks for any help, alex ASSERT failure in QCoreApplication::sendEvent: "Cannot send events to objects owned by a different thread. Current thread 82c31e8. Receiver 'MainWindow' (of type 'MainWindow') was created in thread 81f5060", file kernel/qcoreapplication.cpp, line 269 Aborted (core dumped)

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