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  • MultiThreading question

    - by TiGer
    Hi, I am developing on Android but the question might be just as valid on any other Java platform. I have developed a multi-threaded app. Lets say I have a first class that needs to do a time-intensive task, thus this work is done in another Thread. When it's done that same Thread will return the time-intensive task result to another (3rd) class. This last class will do something and return it's result to the first-starting class. I have noticed though that the first class will be waiting the whole time, maybe because this is some kind of loop ? Also I'd like the Thread-class to stop itself, as in when it has passed it's result to the third class it should simply stop. The third class has to do it's work without being "incapsulated" in the second class (the Thread one). Anyone knows how to accomplish this ? right now the experience is that the first one seems to be waiting (hanging) till the second and the third one are done :(

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  • can a python script know that another instance of the same script is running... and then talk to it?

    - by Justin Grant
    I'd like to prevent multiple instances of the same long-running python command-line script from running at the same time, and I'd like the new instance to be able to send data to the original insance before the new instance commits suicide. How can I do this in a cross-platform way? Specifically, I'd like to enable the following behavior: "foo.py" is launched from the command line, and it will stay running for a long time-- days or weeks until the machine is rebooted or the parent process kills it. every few minutes the same script is launched again, but with different command-line parameters when launched, the script should see if any other instances are running. if other instances are running, then instance #2 should send its command-line parameters to instance #1, and then instance #2 should exit. instance #1, if it receives command-line parameters from another script, should spin up a new thread and (using the command-line parameters sent in the step above) start performing the work that instance #2 was going to perform. So I'm looking for two things: how can a python program know another instance of itself is running, and then how can one python command-line program communicate with another? Making this more complicated, the same script needs to run on both Windows and Linux, so ideally the solution would use only the Python standard library and not any OS-specific calls. Although if I need to have a Windows codepath and an *nix codepath (and a big if statement in my code to choose one or the other), that's OK if a "same code" solution isn't possible. I realize I could probably work out a file-based approach (e.g. instance #1 watches a directory for changes and each instance drops a file into that directory when it wants to do work) but I'm a little concerned about cleaning up those files after a non-graceful machine shutdown. I'd ideally be able to use an in-memory solution. But again I'm flexible, if a persistent-file-based approach is the only way to do it, I'm open to that option. More details: I'm trying to do this because our servers are using a monitoring tool which supports running python scripts to collect monitoring data (e.g. results of a database query or web service call) which the monitoring tool then indexes for later use. Some of these scripts are very expensive to start up but cheap to run after startup (e.g. making a DB connection vs. running a query). So we've chosen to keep them running in an infinite loop until the parent process kills them. This works great, but on larger servers 100 instances of the same script may be running, even if they're only gathering data every 20 minutes each. This wreaks havoc with RAM, DB connection limits, etc. We want to switch from 100 processes with 1 thread to one process with 100 threads, each executing the work that, previously, one script was doing. But changing how the scripts are invoked by the monitoring tool is not possible. We need to keep invocation the same (launch a process with different command-line parameters) but but change the scripts to recognize that another one is active, and have the "new" script send its work instructions (from the command line params) over to the "old" script.

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  • Python — Time complexity of built-in functions versus manually-built functions in finite fields

    - by stackuser
    Generally, I'm wondering about the advantages versus disadvantages of using the built-in arithmetic functions versus rolling your own in Python. Specifically, I'm taking in GF(2) finite field polynomials in string format, converting to base 2 values, performing arithmetic, then output back into polynomials as string format. So a small example of this is in multiplication: Rolling my own: def multiply(a,b): bitsa = reversed("{0:b}".format(a)) g = [(b<<i)*int(bit) for i,bit in enumerate(bitsa)] return reduce(lambda x,y: x+y,g) Versus the built-in: def multiply(a,b): # a,b are GF(2) polynomials in binary form .... return a*b #returns product of 2 polynomials in gf2 Currently, operations like multiplicative inverse (with for example 20 bit exponents) take a long time to run in my program as it's using all of Python's built-in mathematical operations like // floor division and % modulus, etc. as opposed to making my own division, remainder, etc. I'm wondering how much of a gain in efficiency and performance I can get by building these manually (as shown above). I realize the gains are dependent on how well the manual versions are built, that's not the question. I'd like to find out 'basically' how much advantage there is over the built-in's. So for instance, if multiplication (as in the example above) is well-suited for base 10 (decimal) arithmetic but has to jump through more hoops to change bases to binary and then even more hoops in operating (so it's lower efficiency), that's what I'm wondering. Like, I'm wondering if it's possible to bring the time down significantly by building them myself in ways that maybe some professionals here have already come across.

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  • Newbie, deciding Python or Erlang

    - by Joe
    Hi Guys, I'm a Administrator (unix, Linux and some windows apps such as Exchange) by experience and have never worked on any programming language besides C# and scripting on Bash and lately on powershell. I'm starting out as a service provider and using multiple network/server monitoring tools based on open source (nagios, opennms etc) in order to monitor them. At this moment, being inspired by a design that I came up with, to do more than what is available with the open source at this time, I would like to start programming and test some of these ideas. The requirement is that a server software that captures a stream of data and store them in a database(CouchDB or MongoDB preferably) and the client side (agent installed on a server) would be sending this stream of data on a schedule of every 10 minutes or so. For these two core ideas, I have been reading about Python and Erlang besides ruby. I do plan to use either Amazon or Rackspace where the server platform would run. This gives me the scalability needed when we have more customers with many servers. For that reason alone, I thought Erlang was a better fit(I could be totally wrong, new to this game) and I understand that Erlang has limited support in some ways compared to Ruby or Python. But also I'm totally new to the programming realm of things and any advise would be appreciated grately. Jo

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  • Where can I find out the following info on python (coming from Ruby)

    - by Michael Durrant
    I'm coming from Ruby and Ruby on Rails to Python. Where can I find or find resources about: The command prompt, what is python's version of 'irb' django, what is a good resource for installing, using, etc. pythoncasts... is there anything like railscats, i.e. good video tutorials web sites with the api info about what version have what and which to use. info and recommendations on editors, plugins and IDE's common gotchas for newbies and good things to know at the outset scaling issues, common reasons what is the equivalent of 'gems', i.e. components I can plug in what are popular plugins for django authentication and forms similar to devise and simple_form testing, what's available, anything similar to rspec? database adapters - any preferences? framework info - is django MVC like rails? OO'yness. Is everything an object that gets send messages? Different paradign? syntax - anything like jslint for checking for well-formed code?

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  • python: os.system does not execute shell comand

    - by capoluca
    I need to execute shell command in python program (I have ubuntu). More specifically I want to create graph using graphviz in python script. My code is os.system("dot -Tpng graph.dot -o graph.png") It does not work, but if I just type dot -Tpng graph.dot -o graph.png in command line then everything is fine. Do you know what the problem? Thank you! Edit: Does not work means that nothing happens, there are no errors. Output from dot -v -Tpng graph.dot -o graph.png: dot - graphviz version 2.26.3 (20100126.1600) Activated plugin library: libgvplugin_pango.so.6 Using textlayout: textlayout:cairo Activated plugin library: libgvplugin_dot_layout.so.6 Using layout: dot:dot_layout Using render: cairo:cairo Using device: png:cairo:cairo The plugin configuration file: /usr/lib/graphviz/config6 was successfully loaded. render : cairo dot fig gd map ps svg tk vml vrml xdot layout : circo dot fdp neato nop nop1 nop2 osage patchwork sfdp twopi textlayout : textlayout device : canon cmap cmapx cmapx_np dot eps fig gd gd2 gif gv imap imap_np ismap jpe jpeg jpg pdf plain plain-ext png ps ps2 svg svgz tk vml vmlz vrml wbmp x11 xdot xlib loadimage : (lib) eps gd gd2 gif jpe jpeg jpg png ps svg

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  • Ruby or Python?

    - by Bobby Tables
    Hi all, This question is extremely subjective and open-ended. It might even sound like something I should just research for myself and make my own decision. But I'd like to put it out there and get some thoughts from others. Long story short - I burned out with the rat race and am on a self-funded sabbatical this year. Much of it is to take a break from the corporate grind and travel around, but I also want to play around with new technologies and do some self-learning projects, to stay up to speed on programming, and well - I just love tinkering with programming, when there's no pressure! Here's the thing: I am a lifetime C/C++/Java programmer. I'm a bit of a squiggly bracket snob since I've been working with this family of languages for my entire programming career. So I'd like to learn a language which isn't so closely syntactically related to this group. What I'm basically looking for is a language which is relatively general purpose, fun to learn, has some new concepts that are different from C++/Java, and has a good community. A secondary consideration is that it has good web development frameworks. A tertiary consideration is that it's not totally academic (read: there are real world jobs out there using it). I've narrowed it down to Ruby or Python. My impression of Ruby is that it is extremely web oriented - that the only real application of it is as a server side scripting language for doing web stuff (mainly Ruby on Rails). For Python I'm not so sure. TL;DR and to put it as succinctly as possible: which of these would be better for a C++/Java guy to learn to get some new perspectives on programming? And which is more open and general purpose and applicable to a wider set of applications? I'm leaning towards Ruby at the moment, but I worry to an extent that it looks like it's used as nothing but a server side web language.

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  • How to distribute python GTK applications?

    - by Nik
    This is in correlation with the previous question I asked here. My aim is to create and package an application for easy installation in Ubuntu and other debian distributions. I understand that the best way to do this is by creating .deb file with which users can easily install my application on their system. However, I would also like to make sure my application is available in multiple languages. This is why I raised the question before which you can read here. In the answers that were provided, I was asked to use disutils for my packaging. I am however missing the bigger picture here. Why is there a need to include a setup.py file when I distribute my application in .deb format? My purpose is to ensure that users do not need to perform python setup.py to install my application but rather just click on the .deb file. I already know how to create a deb file from the excellent tutorial available here. It clearly shows how to edit rules, changelog and everything required to create a clean deb file. You can look at my application source code and folder structure at Github if it helps you better understand my situation. Please note I have glanced through the official python documentation found here. But I am hoping that I would get an answer which would help even a lame man understand since my knowledge is pretty poor in this regard.

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  • Strategies for managUse of types in Python

    - by dave
    I'm a long time programmer in C# but have been coding in Python for the past year. One of the big hurdles for me was the lack of type definitions for variables and parameters. Whereas I totally get the idea of duck typing, I do find it frustrating that I can't tell the type of a variable just by looking at it. This is an issue when you look at someone else's code where they've used ambiguous names for method parameters (see edit below). In a few cases, I've added asserts to ensure parameters comply with an expected type but this goes against the whole duck typing thing. On some methods, I'll document the expected type of parameters (eg: list of user objects), but even this seems to go against the idea of just using an object and let the runtime deal with exceptions. What strategies do you use to avoid typing problems in Python? Edit: Example of the parameter naming issues: If our code base we have a task object (ORM object) and a task_obj object (higher level object that embeds a task). Needless to say, many methods accept a parameter named 'task'. The method might expect a task or a task_obj or some other construct such as a dictionary of task properties - it is not clear. It is them up to be to look at how that parameter is used in order to work out what the method expects.

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  • Strategies for managing use of types in Python

    - by dave
    I'm a long time programmer in C# but have been coding in Python for the past year. One of the big hurdles for me was the lack of type definitions for variables and parameters. Whereas I totally get the idea of duck typing, I do find it frustrating that I can't tell the type of a variable just by looking at it. This is an issue when you look at someone else's code where they've used ambiguous names for method parameters (see edit below). In a few cases, I've added asserts to ensure parameters comply with an expected type but this goes against the whole duck typing thing. On some methods, I'll document the expected type of parameters (eg: list of user objects), but even this seems to go against the idea of just using an object and let the runtime deal with exceptions. What strategies do you use to avoid typing problems in Python? Edit: Example of the parameter naming issues: If our code base we have a task object (ORM object) and a task_obj object (higher level object that embeds a task). Needless to say, many methods accept a parameter named 'task'. The method might expect a task or a task_obj or some other construct such as a dictionary of task properties - it is not clear. It is them up to be to look at how that parameter is used in order to work out what the method expects.

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  • Python and mechanize login script

    - by Perun
    Hi fellow programmers! I am trying to write a script to login into my universities "food balance" page using python and the mechanize module... This is the page I am trying to log into: http://www.wcu.edu/11407.asp The website has the following form to login: <FORM method=post action=https://itapp.wcu.edu/BanAuthRedirector/Default.aspx><INPUT value=https://cf.wcu.edu/busafrs/catcard/idsearch.cfm type=hidden name=wcuirs_uri> <P><B>WCU ID Number<BR></B><INPUT maxLength=12 size=12 type=password name=id> </P> <P><B>PIN<BR></B><INPUT maxLength=20 type=password name=PIN> </P> <P></P> <P><INPUT value="Request Access" type=submit name=submit> </P></FORM> From this we know that I need to fill in the following fields: 1. name=id 2. name=PIN With the action: action=https://itapp.wcu.edu/BanAuthRedirector/Default.aspx This is the script I have written thus far: #!/usr/bin/python2 -W ignore import mechanize, cookielib from time import sleep url = 'http://www.wcu.edu/11407.asp' myId = '11111111111' myPin = '22222222222' # Browser #br = mechanize.Browser() #br = mechanize.Browser(factory=mechanize.DefaultFactory(i_want_broken_xhtml_support=True)) br = mechanize.Browser(factory=mechanize.RobustFactory()) # Use this because of bad html tags in the html... # Cookie Jar cj = cookielib.LWPCookieJar() br.set_cookiejar(cj) # Browser options br.set_handle_equiv(True) br.set_handle_gzip(True) br.set_handle_redirect(True) br.set_handle_referer(True) br.set_handle_robots(False) # Follows refresh 0 but not hangs on refresh > 0 br.set_handle_refresh(mechanize._http.HTTPRefreshProcessor(), max_time=1) # User-Agent (fake agent to google-chrome linux x86_64) br.addheaders = [('User-agent','Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/535.11 (KHTML, like Gecko) Chrome/17.0.963.56 Safari/535.11'), ('Accept', 'text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8'), ('Accept-Encoding', 'gzip,deflate,sdch'), ('Accept-Language', 'en-US,en;q=0.8'), ('Accept-Charset', 'ISO-8859-1,utf-8;q=0.7,*;q=0.3')] # The site we will navigate into br.open(url) # Go though all the forms (for debugging only) for f in br.forms(): print f # Select the first (index two) form br.select_form(nr=2) # User credentials br.form['id'] = myId br.form['PIN'] = myPin br.form.action = 'https://itapp.wcu.edu/BanAuthRedirector/Default.aspx' # Login br.submit() # Wait 10 seconds sleep(10) # Save to a file f = file('mycatpage.html', 'w') f.write(br.response().read()) f.close() Now the problem... For some odd reason the page I get back (in mycatpage.html) is the login page and not the expected page that displays my "cat cash balance" and "number of block meals" left... Does anyone have any idea why? Keep in mind that everything is correct with the header files and while the id and pass are not really 111111111 and 222222222, the correct values do work with the website (using a browser...) Thanks in advance EDIT Another script I tried: from urllib import urlopen, urlencode import urllib2 import httplib url = 'https://itapp.wcu.edu/BanAuthRedirector/Default.aspx' myId = 'xxxxxxxx' myPin = 'xxxxxxxx' data = { 'id':myId, 'PIN':myPin, 'submit':'Request Access', 'wcuirs_uri':'https://cf.wcu.edu/busafrs/catcard/idsearch.cfm' } opener = urllib2.build_opener() opener.addheaders = [('User-agent','Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/535.11 (KHTML, like Gecko) Chrome/17.0.963.56 Safari/535.11'), ('Accept', 'text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8'), ('Accept-Encoding', 'gzip,deflate,sdch'), ('Accept-Language', 'en-US,en;q=0.8'), ('Accept-Charset', 'ISO-8859-1,utf-8;q=0.7,*;q=0.3')] request = urllib2.Request(url, urlencode(data)) open("mycatpage.html", 'w').write(opener.open(request)) This has the same behavior...

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  • Python 2.7 list of lists manipulation functionality

    - by user3688163
    I am trying to perform several operations on the myList list of lists below and am having some trouble figuring it out. I am very new to Python. myList = [ ['Issue Id','1.Completeness for OTC','Break',3275,33,33725102303,296384802,20140107], ['Issue Id','2.Validity check1 for OTC','Break',3308,0,34021487105,0,20140107], ['Issue Id','3.Validity check2 for OTC','Break',3308,0,34021487105,0,20140107], ['Issue Id','4.Completeness for RST','Break',73376,1,8.24931E+11,44690130,20140107], ['Issue Id','5.Validity check1 for RST','Break',73377,0,8.24976E+11,0,20140107], ['Liquidity','1. OTC - Null','Break',7821 0,2.28291E+11,0,20140110], ['Liquidity','2. OTC - Unmapped','Break',7778,43,2.27712E+11,579021732.8,20140110], ['Liquidity','3. RST - Null','Break',335120,0,1.01425E+12,0,20140110], ['Liquidity','4. RST - Unmapped','Break',334608,512,1.01351E+12,735465433.1,20140110], ['Liquidity','5. RST - Valid','Break',335120,0,1.01425E+12,0,20140110], ['Issue Id','1.Completeness for OTC','Break',3292,33,32397924450,306203929,20140110], ['Issue Id','2.Validity check1 for OTC','Break',3325,0,32704128379,0,20140110], ['Issue Id','3.Validity check2 for OTC','Break',3325,0,32704128379,0,20140110], ['Issue Id','4.Completeness for RST','Break',73594,3,8.5352E+11,69614602,20140110], ['Issue Id','5.Validity check1 for RST','Break',73597,0,8.5359E+11,0,20140110], ['Unlinked Silver ID','DQ','Break',3201318,176,20000000,54974.33386,20140101], ['Missing GCI','DQ','Break',3201336,158,68000000,49351.9588,20140101], ['Missing Book','DQ Break',3192720,8774,3001000000,2740595.484,20140101], ['Matured Trades','DQ','Break',3201006,488,1371000000,152428.8348,20140101], ['Illiquid Trades','1.Completeness Check for range','Break',43122,47,88597695671,54399061.43,20140107], ['Illiquid Trades','2.Completeness Check for non','Break',39033,0,79133622401,0,20140107] ] I am trying to get the result below but do not know how to do so: newList = [ ['Issue Id','1.Completeness for OTC:2.Validity check1 for OTC:3.Validity check2 for OTC','Break',3275,33,33725102303,296384802,20140107], ['Issue Id','4.Completeness for RST:5.Validity check1 for RST','Break',73376,1,8.24931E+11,44690130,20140107], ['Liquidity','1. OTC - Null','Break:2. OTC - Unmapped','Break',7821 0,2.28291E+11,0,20140110], ['Liquidity','3. RST - Null:4. RST - Unmapped:5. RST - Valid','Break',335120,0,1.01425E+12,0,20140110], ['Issue Id','1.Completeness for OTC:2.Validity check1 for OTC:3.Validity check2 for OTC','Break',3292,33,32397924450,306203929,20140110], ['Issue Id','4.Completeness for RST:5. RST - Valid','Break',73594,3,8.5352E+11,69614602,20140110], ['Unlinked Silver ID','DQ','Break',3201318,176,20000000,54974.33386,20140101], ['Missing GCI','DQ','Break',3201336,158,68000000,49351.9588,20140101], ['Missing Book','DQ Break',3192720,8774,3001000000,2740595.484,20140101], ['Matured Trades','DQ','Break',3201006,488,1371000000,152428.8348,20140101], ['Illiquid Trades','1.Completeness Check for range','Break',43122,47,88597695671,54399061.43,20140107], ['Illiquid Trades','2.Completeness Check for non','Break',39033,0,79133622401,0,20140107] ] Rules to create newList. Create a new list in the newList list of lists if the values in the lists meet the following conditions: multiple lists that match on `myList[i][0]` and `myList[i][7]` but with have (1) sums of `myList[i][3]` and `myList[i][4]` and (2) sums of `myList[i][5]` and `myList[i][6]` that are different from each other are just listed as is in newList if multiple lists match on both `myList[i][0]` (this is the type) and `myList[i][7]` (this is the date) are the same then create a new list for each set of lists with mathcing `myList[i][0]` and `myList[i][7]` that have (1) sums of `myList[i][3]` and `myList[i][4]` and (2) sums of `myList[i][5]` and `myList[i][6]` that are different from the other lists with mathcing `myList[i][0]` and `myList[i][7]`. I also am trying to concatenate `myList[i][1]` separated by a ':' for all those lists with matching `myList[i][0]` and `myList[i][7]` and with sums of `myList[i][3]` + `myList[i][4]` and `myList[i][5]` + `myList[i][6]` that match. So essentially for this case only those lists in `myList` with sums of `myList[i][3]` + `myList[i][4]` and `myList[i][5]` + `myList[i][6]` are different from the other lists are then listed in newList. The above newList illustrates these results I am trying to achieve. If anyone has any ideas how to do this they would be greatly appreciated. Thank you!

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  • Trac FastCGI + Python on dreamhost leaves zombie python running

    - by Katsuke
    Hello there, Recently I installed trac in one of my dreamhost domains. I followed the instructions of http://trac.mlalonde.net/wiki/CreamyTrac and everything worked perfectly. At least i thought that was the case. After a few days, i started to notice that i was getting random 500 pages. I quickly checked the error log, and found a bunch of: [Fri Apr 16 14:35:34 2010] [error] [client *.*.*.*] Premature end of script headers: dispatch.fcgi [Fri Apr 16 14:35:54 2010] [error] [client *.*.*.*] Premature end of script headers: dispatch.fcgi, referer: http://www.trac.****.com/login [Fri Apr 16 16:05:58 2010] [error] [client *.*.*.*] Premature end of script headers: dispatch.fcgi, referer: http://www.trac.****.com/timeline The trac instance has very low traffic so it is possible that this might have been triggered faster if there was more use of it. So next step i went to look at top and am amazed by what i see: (this is NOT exactly what i saw, i just reproduced this from memory) 23730 rl_inst 20 0 44516 15m 4012 S 0.0 0.4 0:00.17 python2.4 23731 rl_inst 20 0 44616 15m 4012 S 0.0 0.4 0:03.17 python2.4 23732 rl_inst 20 0 44116 15m 4012 S 0.0 0.4 0:01.17 python2.4 23733 rl_inst 20 0 44826 15m 4012 S 0.0 0.4 0:04.17 python2.4 23734 rl_inst 20 0 44216 15m 4012 S 0.0 0.4 0:02.17 python2.4 23735 rl_inst 20 0 44416 15m 4012 S 0.0 0.4 0:01.17 python2.4 I opened the trac site again and that changed to this: 23730 rl_inst 20 0 44516 15m 4012 S 0.0 0.4 0:00.17 python2.4 23731 rl_inst 20 0 44616 15m 4012 S 0.0 0.4 0:03.17 python2.4 23732 rl_inst 20 0 44116 15m 4012 S 0.0 0.4 0:01.17 python2.4 23733 rl_inst 20 0 44826 15m 4012 S 0.0 0.4 0:04.17 python2.4 23734 rl_inst 20 0 44216 15m 4012 S 0.0 0.4 0:02.17 python2.4 23735 rl_inst 20 0 44416 15m 4012 S 0.0 0.4 0:01.17 python2.4 28378 rl_inst 20 0 2608 1208 1008 S 0.0 0.0 0:00.00 dispatch.fcgi 28382 rl_inst 20 0 44248 15m 4012 S 0.0 0.4 0:02.19 python2.4 So the dispatch.fcgi was being called correctly and was spawning correctly other python2.4 process. After the IDLE time passed this is the results: 23730 rl_inst 20 0 44516 15m 4012 S 0.0 0.4 0:00.17 python2.4 23731 rl_inst 20 0 44616 15m 4012 S 0.0 0.4 0:03.17 python2.4 23732 rl_inst 20 0 44116 15m 4012 S 0.0 0.4 0:01.17 python2.4 23733 rl_inst 20 0 44826 15m 4012 S 0.0 0.4 0:04.17 python2.4 23734 rl_inst 20 0 44216 15m 4012 S 0.0 0.4 0:02.17 python2.4 23735 rl_inst 20 0 44416 15m 4012 S 0.0 0.4 0:01.17 python2.4 28382 rl_inst 20 0 44248 15m 4012 S 0.0 0.4 0:02.19 python2.4 dispatch.fcgi was gone but the corresponding python2.4 was still there o_O. I had started with 5 sleeping processes of python and after idle time i ended up with 6. I repeated this and found that it kept spawning more and more python2.4, this was indeed what was causing my 500s indirectly. Let me explain my findings. Am on a shared hosting so my processes get killed if they are way too many. So everytime i opened trac 2 new processes spawned and one remained, to the point that dreamhost was killing a random process when i reached my limit. Sometimes killing the python2.4 that actually was rendering the current page. Hence header premature ending, python is gone the .fcgi doesnt know what to do and throws an 500. I found a dirty solution to this. I changed my dispatch.fcgi to contain a line that killed any currently running python2.4 process and then spawn a new one. Since then i dont get any rogues what so ever. But i dont think this is the best solution, calling killall in every fcgi just seems wrong. Anyone has run into this issue and found a cleaner solution? Is there anything that i have overlooked?

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  • How to set up Mod_WSGI for Python on Ubuntu

    - by AutomatedTester
    Hi, I am trying to setup MOD_WSGI on my Ubuntu box. I have found steps that said I needed to do the following steps I found at http://ubuntuforums.org/showthread.php?t=833766 sudo apt-get install libapache2-mod-wsgi sudo a2enmod mod-wsgi sudo /etc/init.d/apache2 restart sudo gedit /etc/apache2/sites-available/default and update the Directory <Directory /var/www/> Options Indexes FollowSymLinks MultiViews ExecCGI AddHandler cgi-script .cgi AddHandler wsgi-script .wsgi AllowOverride None Order allow,deny allow from all </Directory> sudo /etc/init.d/apache2 restart Created test.wsgi with def application(environ, start_response): status = '200 OK' output = 'Hello World!' response_headers = [('Content-type', 'text/plain'), ('Content-Length', str(len(output)))] start_response(status, response_headers) return [output] Step 2 fails because it says it can't find mod-wsgi even though the apt-get found it. If I carry on with the steps the python app just shows as plain text in a browser. Any ideas what I have done wrong? EDIT: Results for questions asked automatedtester@ubuntu:~$ dpkg -l libapache2-mod-wsgi Desired=Unknown/Install/Remove/Purge/Hold | Status=Not/Inst/Cfg-files/Unpacked/Failed-cfg/Half-inst/trig-aWait/Trig-pend |/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad) ||/ Name Version Description +++-======================================-======================================-============================================================================================ ii libapache2-mod-wsgi 2.5-1 Python WSGI adapter module for Apache automatedtester@ubuntu:~$ dpkg -s libapache2-mod-wsgi Package: libapache2-mod-wsgi Status: install ok installed Priority: optional Section: python Installed-Size: 376 Maintainer: Ubuntu MOTU Developers <[email protected]> Architecture: i386 Source: mod-wsgi Version: 2.5-1 Depends: apache2, apache2.2-common, libc6 (>= 2.4), libpython2.6 (>= 2.6), python (>= 2.5), python (<< 2.7) Suggests: apache2-mpm-worker | apache2-mpm-event Conffiles: /etc/apache2/mods-available/wsgi.load 06d2b4d2c95b28720f324bd650b7cbd6 /etc/apache2/mods-available/wsgi.conf 408487581dfe024e8475d2fbf993a15c Description: Python WSGI adapter module for Apache The mod_wsgi adapter is an Apache module that provides a WSGI (Web Server Gateway Interface, a standard interface between web server software and web applications written in Python) compliant interface for hosting Python based web applications within Apache. The adapter provides significantly better performance than using existing WSGI adapters for mod_python or CGI. Original-Maintainer: Debian Python Modules Team <[email protected]> Homepage: http://www.modwsgi.org/ automatedtester@ubuntu:~$ sudo a2enmod libapache2-mod-wsgi ERROR: Module libapache2-mod-wsgi does not exist! automatedtester@ubuntu:~$ sudo a2enmod mod-wsgi ERROR: Module mod-wsgi does not exist! FURTHER EDIT FOR RMYates automatedtester@ubuntu:~$ apache2ctl -t -D DUMP_MODULES apache2: Could not reliably determine the server's fully qualified domain name, using 127.0.1.1 for ServerName Loaded Modules: core_module (static) log_config_module (static) logio_module (static) mpm_worker_module (static) http_module (static) so_module (static) alias_module (shared) auth_basic_module (shared) authn_file_module (shared) authz_default_module (shared) authz_groupfile_module (shared) authz_host_module (shared) authz_user_module (shared) autoindex_module (shared) cgid_module (shared) deflate_module (shared) dir_module (shared) env_module (shared) mime_module (shared) negotiation_module (shared) python_module (shared) setenvif_module (shared) status_module (shared) Syntax OK automatedtester@ubuntu:~$

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  • Which key:value store to use with Python?

    - by Kurt
    So I'm looking at various key:value (where value is either strictly a single value or possibly an object) stores for use with Python, and have found a few promising ones. I have no specific requirement as of yet because I am in the evaluation phase. I'm looking for what's good, what's bad, what are the corner cases these things handle well or don't, etc. I'm sure some of you have already tried them out so I'd love to hear your findings/problems/etc. on the various key:value stores with Python. I'm looking primarily at: memcached - http://www.danga.com/memcached/ python clients: http://pypi.python.org/pypi/python-memcached/1.40 http://www.tummy.com/Community/software/python-memcached/ CouchDB - http://couchdb.apache.org/ python clients: http://code.google.com/p/couchdb-python/ Tokyo Tyrant - http://1978th.net/tokyotyrant/ python clients: http://code.google.com/p/pytyrant/ Lightcloud - http://opensource.plurk.com/LightCloud/ Based on Tokyo Tyrant, written in Python Redis - http://code.google.com/p/redis/ python clients: http://pypi.python.org/pypi/txredis/0.1.1 MemcacheDB - http://memcachedb.org/ So I started benchmarking (simply inserting keys and reading them) using a simple count to generate numeric keys and a value of "A short string of text": memcached: CentOS 5.3/python-2.4.3-24.el5_3.6, libevent 1.4.12-stable, memcached 1.4.2 with default settings, 1 gig memory, 14,000 inserts per second, 16,000 seconds to read. No real optimization, nice. memcachedb claims on the order of 17,000 to 23,000 inserts per second, 44,000 to 64,000 reads per second. I'm also wondering how the others stack up speed wise.

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  • Django 1.4.1 error loading MySQLdb module when attempting 'python manage.py shell'

    - by Paul
    I am trying to set up MySQL, and can't seem to be able to enter the Django manage.py shell interpreter. Getting the output below: rrdhcp-10-32-44-126:django pavelfage$ python manage.py shell Traceback (most recent call last): File "manage.py", line 10, in <module> execute_from_command_line(sys.argv) File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/core/management/__init__.py", line 443, in execute_from_command_line utility.execute() File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/core/management/__init__.py", line 382, in execute self.fetch_command(subcommand).run_from_argv(self.argv) File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/core/management/base.py", line 196, in run_from_argv self.execute(*args, **options.__dict__) File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/core/management/base.py", line 232, in execute output = self.handle(*args, **options) File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/core/management/base.py", line 371, in handle return self.handle_noargs(**options) File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/core/management/commands/shell.py", line 45, in handle_noargs from django.db.models.loading import get_models File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/__init__.py", line 40, in <module> backend = load_backend(connection.settings_dict['ENGINE']) File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/__init__.py", line 34, in __getattr__ return getattr(connections[DEFAULT_DB_ALIAS], item) File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/utils.py", line 92, in __getitem__ backend = load_backend(db['ENGINE']) File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/utils.py", line 24, in load_backend return import_module('.base', backend_name) File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/utils/importlib.py", line 35, in import_module __import__(name) File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/backends/mysql/base.py", line 16, in <module> raise ImproperlyConfigured("Error loading MySQLdb module: %s" % e) django.core.exceptions.ImproperlyConfigured: Error loading MySQLdb module: No module named _mysql Any suggestions really appreciated.

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  • When I try to run vim in command line I get Python errors

    - by Eduan
    When I try running vim in the Terminal (so as to follow @romainl's suggestion in my other question) I get lots of Python errors, which all boil down to: IOError: invalid Python installation: unable to open /usr/include/python2.7/pyconfig.h (No such file or directory) Why is this? I can use Python or Sublime Text even, without any problems. The full list of errors is the following: Traceback (most recent call last): File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site.py", line 565, in <module> File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site.py", line 547, in main File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site.py", line 278, in addusersitepackages File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site.py", line 253, in getusersitepackages File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site.py", line 243, in getuserbase File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/sysconfig.py", line 523, in get_config_var File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/sysconfig.py", line 419, in get_config_vars File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/sysconfig.py", line 298, in _init_posix IOError: invalid Python installation: unable to open /usr/include/python2.7/pyconfig.h (No such file or directory) Extra info: I am on Mac OS X Mountain Lion (OS 10.8) EDIT: I tried @BobDunakey idea with no success, the idea was to use sudo. I still get the same errors. EDIT 2: I was able to solve the problem thanks to Zirak's solution, which is the following: http://clearfix.be/2012/08/05/fix-mountain-lion-10-8-python-ioerror-pyconfig-h-error/

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  • setting permissions of python module (python setup install)

    - by SetJmp
    I am configuring a distutils-based setup.py for a python module that is to be installed on a heterogeneous set of resources. Due to the heterogeneity, the location where the module is installed is not the same on each host however disutils picks the host-specific location. I find that the module is installed without o+rx permissions using disutils (in spite of setting umask ahead of running setup.py). One solution is to manually correct this problem, however I would like an automated means that works on heterogeneous install targets. For example, is there a way to extract the ending location of the installation from within setup.py? Any other suggestions? Thanks! SetJmp

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  • Unable to set background image using python (2.7.3), bash and gnome3

    - by malon
    #!/usr/bin/env python import os bashCommand = "gsettings set org.gnome.desktop.background picture-uri file:///home/malon/autowallpaperchanger/" + pic_name print bashCommand os.system(bashCommand) Print result: gsettings set org.gnome.desktop.background picture-uri file:///home/malon/autowallpaperchanger/wallpaper-1252048.jpg Copying and pasting the print result into a terminal makes the change successfully, so the command is correct, but os.system isn't processing the request correctly for some reason. In the full script (posted below), I use os.system for a different reason immediately before (wget) and that works fine. Thank you! Full script: http://pastebin.com/R90GTmBZ

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  • Python and only Python for almost any programming tasks!

    - by Wassim
    Am I wrong if I think that Python is all I need to master, in order to solve most of the common programming tasks? EDIT I'm not OK with learning new programming languages if they don't teach me new concepts of programming and problem solving; hence the idea behind mastering a modern, fast evolving, with a rich set of class libraries, widely used and documented, and of course has a "friendly" learning curve programming language. I think that in the fast evolving tech industry, specialization is key to success.

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  • Pygame Import Error, Python 3.2

    - by Treb Nicholas
    I'm having an issue with the Pygame module. I run Python 3.2 and installed the respective Pygame file, but now when I try to import it in the IDLE, it gives me this error: import pygame Traceback (most recent call last): File "", line 1, in import pygame File "C:\Python32\lib\site-packages\pygame__init__.py", line 95, in from pygame.base import * ImportError: DLL load failed: %1 is not a valid Win32 application. Any help will be appreciated.

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  • Need help understanding a recursion example in Python

    - by Ali Mustafa
    Python is my first programming language, and I'm learning it from "How to Think Like a Computer Scientist". In Chapter 5 the author gives the following example on recursion: def factorial(n): if n == 0: return 1 else: recurse = factorial(n-1) result = n * recurse return result I understand that if n = 3, then the function will execute the second branch. But what I don't understand is what happens when the function enters the second branch. Can someone explain it to me?

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  • Fix Nautilus URIs in a Python script

    - by Pablo
    I have a very basic Python script I wrote mostly for learning purposes. It opens a terminal in the current folder. However, I can't get it to work in folders with accented characters in the URI (e.g.: /home/pablo/Vídeos or /home/pablo/Área de Trabalho), because it looks like Nautilus URIs are encoded to those %{number} values. Is there a way to convert these URIs to normalized URIs without having to translate every possible accented value by hand? Thanks in advance!

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  • Pidgin script with Python/ Get Focus Signal

    - by Mr Alles
    I am creating a script in Python to integrate Pidgin with Unity (12.04), I've managed to do the counting notifications system using the Launcher API. But I dont know what event or signal is activated when the conversation window gains focus (To clear the message counter). I've tried some of the signals available on the documentation of Pidgin but none of them worked. Is there any GTK(or anything) event that is triggered when the window chat gets focus?

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