First of all, I'm using Windows, just to make that clear. I am using cmd.exe to manage runserver and the server runs just fine. However, sometimes, on a seemingly random basis, Django simply stops writing to stdout! The server responds to my requests and everything, but nothing gets printed.
To make it even clearer, I'm not even talking about print in my Django code, so that cannot be the problem. I'm talking about when it prints e.g. GET /someurl HTTP/1.1, yada-yada... Hitting Ctrl+Break and restarting the server doesn't help. However, if I exit the command prompt and start a new one and run the server in that one, it starts working again.
Any ideas about what's going on? This is with Django 1.0.2 final and Python 2.6.2.
Maybe a bit of a stretch,but under Python 2.6 under Linux using the Twisted framework (instead of Django), I had this behaviour occur anytime my application sent a NULL to stdout and stdout was redirected to syslog. I had assumed this was a bug in the twisted framework's syslog implementation, but maybe its something more. Can you tell from either logging or client activity what the last thing it was doing before losing stdout and see if it is a) always in one of a handful of places and 2) if you are sending anything funky out at the time?
Do you assign something to sys.stdout or sys.stderr at some point in your code?
The development server can act weird sometimes, just stop it with ctrl-break then start it again.
One thing you can try, just to be sure that the server itself didn't stop, is do a hard-refresh (ctrl-F5), if it doesn't respond, then the server is actually dead, and you were just seeing the cached version of the page.
This may seem stupid, but did you check the log files? Also, you could make a lot of requests from urllib, or whatever web client you want, and try to reproduce that. Maybe you'll see a pattern as to why this happens.
Related
I am running an ssh tunnel from an application using a QProcess:
QProcess* process = new QProcess();
process->start("ssh", QStringList()<<"-L"<<"27017:localhost:27017"<<"example.com");
So far it works great, the only problem being that there is no way for me to see when the port has actually been created.
When I run the command on a shell, it takes about 10 seconds to connect to the remote host after which the forwarded port is ready for usage. How do I detect it from my application?
EDIT:
As suggested by vahancho, I used the fact that post-connection there is some output on the terminal that can be used to detect that the connection has succeeded. However, there is a line which is run instantly after launch Pseudo-terminal will not be allocated because stdin is not a terminal, which probably would give a false alarm. The correct output is available in the second signal, emitted a bit later (which is a true indicator of the port having being opened). To get rid of the first message, I am now running ssh using ssh -t -t to force an stdin allocation.
So, the only question left is, can anyone help me without any concerns in this approach?
So, the only question left is, can anyone help me without any concerns in this approach?
This is not a stable and robust solution, unfortunately. It is similarly a broken concept to handling git outputs rather than using an actual library. The main problem is that these softwares do not have any guarantee for output compatibility, rightfully.
Just imagine that what happens if they have an unclear text, a typo, et all, unnoticed. They inherently need to fix the output respectively, and all the applications relying on the output would abruptly break.
This is also the reason behind working on dedicated libraries giving access to the functionality for reuse rather than working with the user facing output directly. In case of git, this means the libgit2 library, for instance.
Qt does not have an ssh mechanism in place by default like you can have such libraries in python, e.g. paramiko.
I would suggest to establish a way in your code by using libssh or libssh2 as you also noted yourself in the comment. I can understand the inconvenience that is not a truly Qt'ish way as of now, but at this point Qt cannot provide anything more robust without third-party.
That being said, it would be nice to see a similar add-on library in the Qt Project for the future, but this may not be happen any soon. If you write your software with proper design in mind, you will be able to switch to such a library withour major issues once someone stands up to maintain such an additional library to Qt or elsewhere.
I had the same problem, but in my case ssh do not output anything - so I couldn't just wait for output. I'm also using ssh to setupt tunnel, so I used QTcpSocket:
program = "ssh";
arguments << m_host << "-N" << "-L" << QString("3306:%1:3306").arg(m_host);
connect(tunnelProcess, &QProcess::started, this, &Database::waitForTunnel);
tunnelProcess->start(program, arguments);
waitForTunnel() slot:
QTcpSocket sock;
sock.connectToHost("127.0.0.1", 3306);
if(sock.waitForConnected(100000))
{
sock.disconnectFromHost();
openDatabaseConnection();
}
else
qDebug() << "timeout";
I hope this will help future people finding this question ;)
I'm developing a small in house alternative to Tripwire, so I've coded a small script to hash files in a JBoss EAP server, and store the path and the hash in a MySQL database.
Every day the script compares the hashes in the filesystem with those saved in the DB, so any change is logged and finally reported using JasperServer.
The script runs at night using cron, to avoid a large number of scripts quering the DB at the same time it uses time.sleep(RANDOM_NUMBER_OF_SECONDS) before doing the fun stuff, but sometimes time.sleep seems to sleep forever and the script ends without any error, I check the mail cron sends and no error is logged. Any help would be appreciated. I'm Using jython-standalone-2.5.3, IBM's JDK and RHEL 5.6 running inside VMWare.
I just found http://bugs.jython.org/issue1974 and a code comment seems to point that OS signals can cause this behavior, but not sure if this is my case.
If you want to see the code checkout at http://code.google.com/p/pysnapshot/
Luis García Bustos.
I don't know why do you think time.sleep() can make less number of scripts querying the DB.
IMO ot is better to use cron to call that program periodically. After it is started it should check if in /tmp/ directory is "semaphore" file, for example /tmp/snapshot_working.txt. If there is no semaphore file, then create it and write to it something like: "snapshot started: 2012-12-05 22:00:00". After your program completes checking it should remove this file. If at start program will find semaphore file then it could just stop or check if date & time saved in this file looks "old". If it is "old", then remove it and start normally writing in log that "old" file was found (administrator can find such long working snaphots and terminate it).
The only reason do make time.sleep() in your case is if you want to use such script at normal working hours without making Denial Of Service attack to your DB. Example: after making 100 DB queries you can make little sleep and give DB time to serve other user queries. But I think the sooner program finishes the better.
I'm developing an app for Symbian device that need to silent filter incoming SMS, and the following link is the code that does that:
http://symbian.devtricks.mobi/tricks/silent_receiving_of_sms_messages/
another similar code on Nokia
http://wiki.forum.nokia.com/index.php/SMS_Utilities_API
It work, but the problem is after I reboot my phone those SMS has been intercept will still add to inbox. I know on the site they did mention to use KIoctlReadMessageSucceeded to prevent that, which I did; but the problem still there. Tried both code but still same result. Is there anything I'm missing?
Another problem with that code is that it will no longer work after a call came in, sms won't be intercept anymore after that. Is that a way to fix that?
Thanks, help would be greatly appreciated.
We regards to not intercepting SMS after a reboot, are you re-starting your executable (and hence the listener) after a reboot?
You can do so with the Nokia startup list management API.
With regards to failing after a call has come in, this sounds like your executable may be panicing (and thus stopping listening). Have you checked to see if it is panicing and whether it is still running after a call has come in?
I've done this kind of application before, and never had any problem with incoming calls.
I'm trying to test the happy-path for a piece of code which takes a long time to respond, and then begins writing a file to the response output stream, which prompts a download dialog in browsers.
The problem is that this process has failed in the past, throwing an exception after this long amount of work. Is there a way in selenium to wait-for-download or equivalent?
I could throw in a Thread.sleep, but that would be inaccurate and unnecessarily slow down the test run.
What should I do, here?
I had the same problem. I invented something to solve the problem. A tempt file is created by Python with '.part' extension. So, if still we have the temp, python can wait for 10 second and check again if the file is downloaded or not yet.
while True:
if os.path.isfile('ts.csv.part'):
sleep(10)
elif os.path.isfile('ts.csv'):
break
else:
sleep(10)
driver.close()
So you have two problems here:
You need to cause the browser to download the file
You need to measure when the downloaded file is complete
Neither problemc an be directly solved by Selenium (yet - 2.0 may help), but both are solvable problems. The first problem can be solved by GUI automation toolkits, such as AutoIT. But they can also be solved by simply sending an automated keypress at the OS level that simulates the enter key (works for Firefox, a little harder on some versions of Chrome and Safari). If you're using Java, you can use Robot to do that. Other languages have similar toolkits to do such a thing.
The second issue is probably best solved with some sort of proxy solution. For example, if your browser was configured to go through a proxy and that proxy had an API, you could query the proxy with that API to ask when network activity had ended.
That's what we do at http://browsermob.com, which is a a startup I founded that uses Selenium to do load testing. We've released some of the proxy code as open source, available at http://browsermob.com/tools.
But two problems still persist:
You need to configure the browser to use the proxy. In Selenium 2 this is easier, but it's possible to do it with Selenium 1 as well. The key is just making sure that your browser launcher brings up the browser with the right profile/settings.
There currently is no API for BrowserMob proxy to tell you when network traffic has stopped! This is a big hole in the concept of the project that I want to fix as soon as I get the time. However, if you're keen to help out, join the Google Group and I can definitely point you in the right direction.
Hope that helps you identify your various options. Best of luck!
This is Chrome-testing-only solution for controlling the downloads with javascript..
Using WebDriver (Selenium2) it can be done within Chrome's chrome:// which is HTML/CSS/Javascript:
driver.get( "chrome://downloads/" );
waitElement( By.CssSelector("#downloads-summary-text") );
// next javascript snippet cancels the last/current download
// if your test ends in file attachment downloading
// you'll very likely need this if you more re-instantiated tests left
((JavascriptExecutor)driver).executeScript("downloads.downloads_[0].cancel_();");
There are other Download.prototype.functions in "chrome://downloads/downloads.js"
This suites you if you just need to test some info note eg. caused by file attachment starting activity, and not the file itself.
Naturally you need to control step 1. - mentioned by Patrick above - and by this you control step 2. FOR THE TEST, not for the functionality of actual file download completion / cancel.
See also : Javascript: Cancel/Stop Image Requests which is relating to Browser stopping.
This falls under the "things that can't be automated" category. Selenium is built with JavaScipt and due to JavaScript sandbox restrictions it can't access downloads.
Selenium 2 might be able to do this once Alerts/Prompts have been implemented but that this won't happen for the next little while yet.
If you want to check for the download dialog, try with AutoIt. I use that for uploading and downloading the files. Using AutoIt with Se RC is easier.
def file_downloaded?(file)
while File.file?(file) == false
p "File downloading in progress..."
sleep 1
end
end
*Ruby Syntax
I am building a sharing-service for maemo5. In the example plugin they are calling ULOG_INFO_L at a lot of places, so I have adopted this for my service as well. The problem is that I can't find where the messages goes.
Reading osso-log.h I should define DEBUG or OSSOLOGCOMPILE, which I do and OSSOLOG_STDOUT or OSSOLOG_SYSLOG. I have tried both settings but can't get anything on syslog or stdout (I have no idea where stdout should end up since I am only calling af-sb-init.sh start), and it's not there anyway :-)
Anyone know where I can find my log?
I found out that when using OSSOLOG_SYSLOG it actually logs to the host machine, not the scratchbox environment.