I recently started developing Django using Pydev in Eclipse, along with several other people I know, and I keep losing several hours of productivity a day to this error that I can't seem to debug. Essentially, sometimes after starting up my django run configuration, I'll go to the URL http://127.0.0.1:8000/foo and it simply spits me back this response:
<h1>Page not found: /foo</h1>
At first I could reproduce this behavior all the time; any time I had multiple workspaces of eclipse open and shut down my Django server once, the server wouldn't actually shut down, but it would just keep serving the page not founds until I shut down both instances of Eclipse.
Stopping doing that and it seemed to work, but then it intermittently seemed to start back up again. When this happens, it will literally not stop happening until I close eclipse, and the eclipse.exe process will hang (and continue to server Page not found pages) until I manually go into the process and kill it. Sometimes, that won't even fix it, and it'll break itself the first time I try to start Django back up.
I'm on the stable build of PyDev and Eclipse 3.6.1.
Any idea what's going on? This is unbelievable frustrating, especially because I tend to like the IDE with this exception.
Are you by any chance using a run configuration to launch your development server? Because that kept happening to me too. It seems that eclipse isn't cleanly closing django when you stop it from the IDE and it's holding on to the http port. In that sense you're sending requests to a zombie server instance, hence the not founds. I have since resorted to launching django from the command line. Not the prettiest solution, I admit.
Related
No, I'm not talking about runserver listening for requests.
Whenever i run makemigrations, migrate or scripts i wrote using django-extensions command runscript, I need to stop the execution of the program before typing in another. This was not the case before restarting my PC this morning.
I'm building a small QR code ticketing app and it was working up until this morning. I fixed a bug regarding opencv since and the app is functional again, but this command line issue is bothering me. I'm going to have to make the /admin and scripts available to a few of my colleagues tomorrow and i'm afraid we won't know when the script running is actually done since it doesn't prompt or allow another command. Having a script executed terminated early because of this would be catastrophic.
whenever i run a command, the blank line not accepting input appears
There's way too much possible reasons why this could've happened; and it's impossible for anyone else to reproduce your scenario just based on what you described. This isn't a widespread issue, so it must something particular to do with your setup.
Run a debugger, like pudb or pdb to find out where the script is stuck on.
Or add a try-except block to catch KeyboardInterrupt to your manage.py and use traceback library to narrow down where it's stuck.
I have a Python app that uses websockets and gevent. It's quite a big application in my personal experience.
I've encountered a problem with it: when I run it on Windows (with 'pipenv run python myapp'), it can (suddenly but very rarily) freeze, and stop accepting messages. If I then enter CTRL+C in cmd, it starts reacting to all the messages, that were issued when it was hanging.
I understand, that it might block somewhere, but I don't know how to debug theses types of errors, because I don't see anything in the code, that could do it. And it happens very rarily on completely different stages of the application's runtime.
What is the best way to debug it? And to actually see what goes behind the scenes? My logs show no indication of a problem.
Could it be an error with cmd and not my app?
Your answer may be as simple as adding timeouts to some of your spawns or gevent calls. Gevent is still single threaded, and so if an IO bound resource hangs, it can't context switch until it's been received. Setting a timeout might help bypass these issues and move your app forward?
I'm working on a simple Flask web application. I use Eclipse/Pydev. When I'm working on the app, I have to restart this app very often because of code changes. And that's the problem. When I run the app, I can see the frame on my localhost, which is good. But when I want to close this app, just click on the red square which should stop applications in Eclipse, sometimes (often), the old version of application keeps running so I can't test the new version. In this case the only thing which helps is to force close every process in Windows Task Manager.
Will you give me any advice how to manage this problem? Thank you in advance.
EDIT: This maybe helps: Many times, I have to run the app twice. Otherwise I can't connect.
I've faced the same problem and solved it. I think it may help.
When we run a flask based site locally it is assigned to a TCP port: 5000 and the Default IP: 127.0.0.1:5000
Sometimes TCP connection remains even after closing the program or terminating the code. So, The idea is kill the TCP connection. You can do it from command-prompt(cmd)
Two Steps to Follow:
1. See the Process ID(PID) for the running TCP connection.
Go to cmd and type:
netstat -ano
Kill The Process By PID. Command for this: taskkill /f /im [PID]. Example is showed bellow.
taskkill /f /im 7332
I've had a very similar thing happen to me. I was using CherryPy rather than Flask, but my solution might still work for you. Oftentimes browsers save webpages locally so that they don't have to re-download them every time the website is visited. This is called caching, and although it's very useful for the average web user, it can be a real pain to app developers. If you're frequently generating new versions of the application, it's possible that your browser is displaying an old version of the app that it has cached instead of the most up to date version. I recommend clearing that cache every time you restart your application, or disabling the cache altogether.
This actually shouldn't happen with the latest versions of PyDev (i.e.: since PyDev 3.4.1: http://pydev.org/history_pydev.html, PyDev should kill all the subprocesses of the main process).
So, can you check which PyDev version are you using?
If you're in the latest version of PyDev, you can use Ctrl+Shift+F9 to terminate/relaunch by default.
But as you're dealing with flask, you should be able to use it to reload automatically on code-changes without doing anything by setting use_reloader=True.
I.e.: I haven't actually tested, but its documentation says that you can set the reload flag for that run(use_reloader=True) -- and PyDev should even be able to debug it (I'll take a better look and improve the PyDev docs on that area later on).
Hi I just started working with Pelican and it really suits my needs, I had tried to build blogs in Flask and other frameworks but I really just wanted something simple so I can post about math, and pelican just works.
My question is when I am testing on my machine, I start the server; however when I stop the server to make some edits to my test blogs, and then try to reload the server I get a socket already in use error. I am stopping my server by ctrl+z am I doing this correctly?
Use ctrl+c to terminate the process. ctrl+z will only send it's execution to the background.
On a separate note, since you are making changes and want to test them it would be more convenient to use $ make devserver instead of $ make serve. See docs.
For your development server, you can also use the script ./develop_server.sh that comes with the last versions of pelican (at least with the 3.5.0).
Build the blog and load a server with ./develop_server.sh start: it reloads each time you edit your blog (except the settings). Simply stop with ./develop_server.sh stop when you're finished.
When you press Ctrl + C or Ctrl + z, do not restart the HTTP server: it is running in the background, and that is the exact reason as why you are getting that error message.
To see that the server is running in the background after pressing the any of the key combinations above, try to edit and save any file: you will see right away in the terminal the re-generation process of your pages is active again.
You can start the HTTP server using this command: make devserver and stop by ./developer_server.sh stop
I'm running a local django development server together with virtualenv and it's been a couple of days that it behaves in a weird way. Sometimes I don't see any log in the console sometimes I see them.
A couple of times I've tried to quit the process and restart it and I've got the port already taken error, so I inspected the running process and there was still an instance of django running.
Other SO answers said that this is due to the autoreload feature, well so why sometimes I have no problem at all and sometimes I do?
Anyway For curiosity I ps aux| grep python and the result is always TWO running process, one from python and one from my activated "virtualenv" python:
/Users/me/.virtualenvs/myvirtualenv/bin/python manage.py runserver
python manage.py runserver
Is this supposed to be normal?
I've solved the mistery: Django was trying to send emails but it could not because of improper configuration, so it was hanging there forever trying to send those emails.
Most probably (I'm not sure here) Django calls an OS function or a subprocess to do so. The point is that the main process was forking itself and giving the job to a subprocess or thread, or whatever, I'm not expert in this.
It turns out that when your python is forked and you kill the father, the children can apparently keep on living after it.
Correct me if I'm wrong.