I'm creating a web app with Django. Since I'm very familiar with Apache I setup my development environment to have Django run through Apache using mod_wsgi. The only annoyance I have with this is that I have to restart Apache everytime I change my code. Is there a way around this?
mod_wsgi is great for production but I think the included server is better for development.
Anyway you should read this about automatic reloading of source code.
I feel like this is really just one of those things most people deal with. It's really not that big of a deal. I made a bash script to make this as easy as possible. I name it 'ra' (reload apache) so it's short and quick. The following works for most apache installs (on UNIX-based systems):
#!/bin/bash
sudo /etc/init.d/apache2 reload
You could probably use some kind of tool to bind this to a key shortcut/foot pedeal/cron.
Related
I have my development environment setup on Win 7 like this:
Django development structure
Apache -server- C:\Program Files (x86)\Apache Software Foundation\Apache2.4
PostgreSQL -database- C:\Program Files\PostgreSQL\9.2
Django -framework- C:\Python27\Lib\site-packages\django
Python -code- C:\Python27
Project -root- C:\mysite
|----------apps
|----------HTML
|----------CSS
|----------JavaScript
|----------assets
I am attempting to keep this extremely simple to start out. There are 5 main directories each with a distinct purpose. All the code resides in the project folder.
compared to WAMP structure:
C:\WAMP
|----------C:\Apache
|----------C:\MySQL
|----------C:\PHP
|----------C:\www
I like how Apache, MySQL, and PHP all reside in a neat directory. I know to keep the root project OUTSIDE in another directory in Django for security reasons.
Is it fine that Apache, PostgreSQL, and Python are installed all over the place in the Django environment?
Did I miss a core Django component and/or directory?
Will deploying and scaling be a problem?
I want this to be a guideline for beginning Django web programmers.
I can answer the question one by one:
Is if fine that Apache, PostgreSQL, and Python are installed all over the place in the Django environment?
All over the place sounds weird but yes it is totally fine.
Did I miss a core Django component and/or directory?
No you don't miss anything, Django core is in site-packages folder already and your site code is mysite, which can be located anywhere you want.
Will deploying and scaling be a problem?
No it won't be a problem with current structure. You will deploy your mysite only, the other will be installed separately.
Something you should get familiar with when starting with Django development:
Most likely when you deploy your project, it will be on a Linux server, so install and learn Linux maybe?
virtualenv: Soon you will have to install Django, then a bunch of external packages to support your project. virtualenv helps you isolate your working environment. Well it's "unofficial" a must when you start with python development.
virtualenvwrapper to make your life easier when working with virtualenv
git and github or bitbucket: if you don't know git yet, you should now.
Apache is just web server, it is used to serve files, but to make a website you do not necessary need it. Django comes with its own development server. See :
python manage.py runserver
Apache is required when you are developing PHP websites because your computer do not know how to compile and interpret it. But for Django, you use the Python language, and you have already install it if you are using Django.
Read https://docs.djangoproject.com/en/1.5/intro/tutorial01/
And where it will be the time to set up your own server using Apache look at :
https://docs.djangoproject.com/en/dev/howto/deployment/wsgi/modwsgi/.
Scaling will be a problem on windows. Python in Apache on windows gets 64 threads in one process. Couple this with the GIL and you will have scaling issues.
Python and Apache on Linux don't have this same problem. Under Linux wsgi can create multiple processes that have multiple threads each, minimizing GIL issues.
WSGI in Apache on windows is not a scalable solution in my opinion.
However you can develop there and move to linux for deployment, I do it all the time.
You will want to take advantage of the Apache Alias directive to serve all your static content like css, js, favicon.ico. This frees up python to only handle requests that require logic.
I'm running ubuntu with nginx with fastcgi, is that all I need to serve python apps also?
You'll probably also need flup to bridge wsgi and fcgi. You obviously need Python, and whatever libraries your app depends upon. Likely need a database and the appropriate connectors as well, but that should all be in the documentation of whatever project you're trying to host (or framework you're using to write with).
Short answer: almost.
I'm running a Django app on Apache + mod_python. When I make some changes to the code, sometimes they have effect immediately, other times they don't, until I restart Apache. However I don't really want to do that since it's a production server running other stuff too. Is there some other way to force that?
Just to make it clear, since I see some people get it wrong, I'm talking about a production environment. For development I'm using Django's development server, of course.
If possible, you should switch to mod_wsgi. This is now the recommended way to serve Django anyway, and is much more efficient in terms of memory and server resources.
In mod_wsgi, each site has a .wsgi file associated with it. To restart a site, just touch the relevant file, and only that code will be reloaded.
As others have suggested, use mod_wsgi instead. To get the ability for automatic reloading, through touching the WSGI script file, or through a monitor that looks for code changes, you must be using daemon mode on UNIX. A slight of hand can be used to achieve same on Windows when using embedded mode. All the details can be found in:
http://code.google.com/p/modwsgi/wiki/ReloadingSourceCode
You can reduce number of connections to 1 by setting "MaxRequestsPerChild 1" in your httpd.conf file. But do it only on test server, not production.
or
If you don't want to kill existing connections and still restart apache you can restart it "gracefully" by performing "apache2ctl gracefully" - all existing connections will be allowed to complete.
Use a test server included in Django. (like ./manage.py runserver 0.0.0.0:8080) It will do most things you would need during development. The only drawback is that it cannot handle simultaneous requests with multi-threading.
I've heard that there is a trick that setting Apache's max instances to 1 so that every code change is reflected immediately--but because you said you're running other services, so this may not be your case.
I'd like to serve django application on windows XP/Vista.
The application is an at hoc web interface to a windows program so it won't be put under heavy load (around 100 requests per second).
Do you know any small servers that can be easily deployed on windows to serve a django app? (IIS is not an option as the app should work on all versions of windows)
cherrypy includes a good server. Here's how you set it up to work with django and some benchmarks.
twisted.web has wsgi support and that could be used to run your django application. Here's how you do it.
In fact any wsgi server will do. Here's one more example, this time using spawning:
$ spawn --factory=spawning.django_factory.config_factory mysite.settings
And for using paste, the info is gathered here.
Of course, you could use apache with mod_wsgi. It would be just another wsgi server. Here are the setup instructions.
If you want to give Apache a go, check out XAMPP to see if it'll work for you. You can do a lightweight (read: no installation) "installation." Of course, you'll also want to install mod_python to run Django. This post may help you set everything up. (Note: I have not used python/Django with XAMPP myself.)
Edit: Before someone points this out, XAMPP is not generally a production-ready tool. It's simply a useful way to see whether Apache will work for you. Also, I saw that you're using SQLite after the fact.
Why not Apache ?
Nokia have developed a scaled down version of apache to run on their mobile phones. It supports python.
http://research.nokia.com/research/projects/mobile-web-server/
Also do you need anything else such as database support etc?
I need to run a simple request/response python module under an
existing system with windows/apache/FastCGI.
All the FastCGI wrappers for python I tried work for Linux only
(they use socket.fromfd() and other such shticks).
Is there a wrapper that runs under windows?
You might find it easier to ditch FastCGI altogether and just run a python webserver on a localhost port. Then just use mod_rewrite to map the apache urls to the internal webserver.
(I started offering FastCGI at my hosting company and to my surprise, nearly everyone ditched it in favor of just running their own web server on the ports I provided them.)
A Django bug suggests that python-fastcgi will work for you, and its PyPI page reports that it works on Windows.
I'd suggest mod_python or mod_wsgi.