Deploying Django using fcgi causes slow page loading - python

I need to deploy my django app on a shared server, where I don't have root access (e.g. httpd.conf) andn all I have is the folder public_html.
Now, I followed the sites describing using fcgi to deploy django (e.g. this). However, the pages load very slowly, I guess the reason is that django needs to be reloaded upon every request? Essentially, I would like a server that runs permanently and simply gets requests from apache.
Before trying out the solution with sockets and so on, I would like to ask for some professional opinions.
thanks!

FCGI sucks. Even its author admits it.
Using Apache ? Try mod_wsgi. It's the most professional deployment solution for apache.
Using Nginx or something else ? Then consider uWSGI. or gunicorn.
Link to a benchmark.

Related

Proper way to build web app with Django on remote web server

I'm fairly new to Django so please excuse my ignorance.
I'm starting my first build of a web app on my remote web server. I am currently SSH'ing to the server and have started the Django project. I just launched the development server for the Django project, and it automatically serves at http://127.0.0.1:8000/.
My question is- what is the proper way to build a Django web app remotely on a server? Am I supposed to build the app on my computer and then transfer the project to my web server after it is complete? Or is there a way for me to access the development server without messing with the domains/ip addresses of the websites that are live on my web server?
Thanks!
This isn't really a Django specific question as the same basic methodology goes for any software development project.
Create different settings files for development and production. For Django this will involve setting the ALLOWED_HOSTS in your production settings as you mentioned as well as other settings. This checklist is helpful for this step. Use environment variables to hide secrets and set them in your development and production machines as appropriate.
Use a version control system such as git and push changes locally and then pull them onto your production server then run your Django server.
Do one better and setup a CI/CD pipeline to automate this
Yes, you're supposed to build working project on your computer :)
You probably cant efficiently write something good on the remote server.
Then you will probably create the git repository, for example on gitlab.
Then you will work on your computer building your project.
When you want to see it on the remote server, you will pull your project there.
It will be a little tricky for a first time to correctly deploy it, but it's not really that bad + there are a lot of good instructions out there, for ex:
https://www.digitalocean.com/community/tutorials/how-to-set-up-django-with-postgres-nginx-and-gunicorn-on-ubuntu-16-04
I hope I correctly understood your question.

How to deploy Django without mod_wsgi

I'm relatively new to web development, but I have a couple years experience working with python, so I figured I would build my first production site using django.
I've spent the last few days learning the basics and building a test site running on my local machine. Today, I've been trying to deploy my site to production; however, I've hit a pretty large stumbling block.
The django documentation suggests using mod_wsgi for apache deployments. I followed the install instructions here, only to realize that I don't have access to make any changes to apache - I'm currently on a shared hosting plan.
Apparently, to perform the install, I would have to upgrade to a VPS plan, which costs a lot more.
Any advice for a new web developer trying to get a proof-of-concept web app together (preferably with feedback gathered from real users) on a budget?
I think I have two options:
Eat the cost on my current web hosting plan. Try to find a cheaper host that specializes in django hosting. I've been looking at the following (suggestions here would be wonderful):
Heroku
DigitalOcean
A2Hosting
Try some sort of manual deployment. Is this possible or has anybody ever made this work? I can't seem to find any resources about this.
I was able to install django on my web server and my site just seems like a collection of files at this point. Can I simply move this directory tree to my site using an ftp? And handle the database migration manually?
Can I just run django on my web server via ssh instead of from my local machine? Essentially just rebuild my site in production? I know this isn't a smart idea with a normal production site, but as a proof of concept, I don't mind some downtime if my code is buggy.
Thanks!
If you are just starting Heroku is probably perfect for you. It's super easy to set up, you don't have to handle the server configuration yourself and it has a free tier to do some tests until you are ready to go.
If you are OK with doing some more advanced server/service configuration, you can use Google Cloud, Azure or AWS. This last one has a one year free tier. If you go this route, I suggest using gunicorn/uwsgi + nginx instead of Apache mod_wsgi.

Can I run Bottle.py on my Apache server without disrupting my PHP apps?

I'm antsy to get Python running on my webserver after just recently picking it up.
I chose Bottle.py because it looks simple, accessible, and contained. I have very little experience with or knowledge of how exactly webservers work (how to mess with them) and I'm reluctant to play with my server's Apache if I don't need to since it hosts a very active message board already.
Bottle's documentation seemed to assume a step or two of server/python understanding that I don't have, as I'm not even sure where to put the actual routes/website content once I already have bottle.py copied over to my doc root. Or how the server knows to run bottle (or execute python) when I go to "mydomain.com".
Run it in a WSGI container such as mod_wsgi.
You can also run Apace as a proxy to your application. I believe using mod_proxy would get you there. I myself run a nginx front end as reverse proxy to a bottle application running on bjoern. Bjoern itself is quite capable of running the bottle app, so I didn't want to use mod_wsgi, and similar stuff.

Apache/Django freezing after a few requests

I'm running Django through mod_wsgi and Apache (2.2.8) on Ubuntu 8.04.
I've been running Django on this setup for about 6 months without any problems. Yesterday, I moved my database (postgres 8.3) to its own server, and my Django site started refusing to load (the browser spinner would just keep spinning).
It works for about 10 mintues, then just stops. Apache is still able to serve static files. Just nothing through Django.
I've checked the apache error logs, and I don't see any entries that could be related. I'm not sure if this is a WSGI, Django, Apache, or Postgres issue?
Any ideas?
Thanks for your help!
It sounds a lot like there's something happening between django and your newly housed database.
Just to eliminate apache from the mix, you should run it as the dev server (on some random port to stop people using it) and see if you still have issues. If you do, it's the database. If it behaves, it could be apache.
Edit, This looks interesting. You can test that by applying his patch (commenting out the .close()) but there are other similar bugs floating around.
Found it! I'm using eventlet in some other code and I imported one of my modules into a django model. So eventlet was taking over and putting everything to "sleep".

Python web programming

Good morning.
As the title indicates, I've got some questions about using python for web development.
What is the best setup for a development environment, more specifically, what webserver to use, how to bind python with it. Preferably, I'd like it to be implementable in both, *nix and win environment.
My major concern when I last tried apache + mod_python + CherryPy was having to reload webserver to see the changes. Is it considered normal? For some reason cherrypy's autoreload didn't work at all.
What is the best setup to deploy a working Python app to production and why? I'm now using lighttpd for my PHP web apps, but how would it do for python compared to nginx for example?
Is it worth diving straight with a framework or to roll something simple of my own? I see that Django has got quite a lot of fans, but I'm thinking it would be overkill for my needs, so I've started looking into CherryPy.
How exactly are Python apps served if I have to reload httpd to see the changes? Something like a permanent process spawning child processes, with all the major file includes happening on server start and then just lazy loading needed resources?
Python supports multithreading, do I need to look into using that for a benefit when developing web apps? What would be that benefit and in what situations?
Big thanks!
What is the best setup for a development environment?
Doesn't much matter. We use Django, which runs in Windows and Unix nicely. For production, we use Apache in Red Hat.
Is having to reload webserver to see the changes considered normal?
Yes. Not clear why you'd want anything different. Web application software shouldn't be dynamic. Content yes. Software no.
In Django, we develop without using a web server of any kind on our desktop. The Django "runserver" command reloads the application under most circumstances. For development, this works great. The times when it won't reload are when we've damaged things so badly that the app doesn't properly.
What is the best setup to deploy a working Python app to production and why?
"Best" is undefined in this context. Therefore, please provide some qualification for "nest" (e.g., "fastest", "cheapest", "bluest")
Is it worth diving straight with a framework or to roll something simple of my own?
Don't waste time rolling your own. We use Django because of the built-in admin page that we don't have to write or maintain. Saves mountains of work.
How exactly are Python apps served if I have to reload httpd to see the changes?
Two methods:
Daemon - mod_wsgi or mod_fastcgi have a Python daemon process to which they connect. Change your software. Restart the daemon.
Embedded - mod_wsgi or mod_python have an embedded mode in which the Python interpreter is inside the mod, inside Apache. You have to restart httpd to restart that embedded interpreter.
Do I need to look into using multi-threaded?
Yes and no. Yes you do need to be aware of this. No, you don't need to do very much. Apache and mod_wsgi and Django should handle this for you.
So here are my thoughts about it:
I am using Python Paste for developing my app and eventually also running it (or any other python web server). I am usually not using mod_python or mod_wsgi as it makes development setup more complex.
I am using zc.buildout for managing my development environment and all dependencies together with virtualenv. This gives me an isolated sandbox which does not interfere with any Python modules installed system wide.
For deployment I am also using buildout/virtualenv, eventually with a different buildout.cfg. I am also using Paste Deploy and it's configuration mechanism where I have different config files for development and deployment.
As I am usually running paste/cherrypy etc. standalone I am using Apache, NGINX or maybe just a Varnish alone in front of it. It depends on what configuration options you need. E.g. if no virtual hosting, rewrite rules etc. are needed, then I don't need a full featured web server in front. When using a web server I usually use ProxyPass or some more complex rewriting using mod_rewrite.
The Python web framework I use at the moment is repoze.bfg right now btw.
As for your questions about reloading I know about these problems when running it with e.g. mod_python but when using a standalone "paster serve ... -reload" etc. it so far works really well. repoze.bfg additionally has some setting for automatically reloading templates when they change. If the framework you use has that should be documented.
As for multithreading that's usually used then inside the python web server. As CherryPy supports this I guess you don't have to worry about that, it should be used automatically. You should just eventually make some benchmarks to find out under what number of threads your application performs the best.
Hope that helps.
+1 to MrTopf's answer, but I'll add some additional opinions.
Webserver
Apache is the webserver that will give you the most configurability. Avoid mod_python because it is basically unsupported. On the other hand, mod_wsgi is very well supported and gives you better stability (in other words, easier to configure for cpu/memory usage to be stable as opposed to spikey and unpredictable).
Another huge benefit, you can configure mod_wsgi to reload your application if the wsgi application script is touched, no need to restart Apache. For development/testing servers you can even configure mod_wsgi to reload when any file in your application is changed. This is so helpful I even run Apache+mod_wsgi on my laptop during development.
Nginx and lighttpd are commonly used for webservers, either by serving Python apps directly through a fastCGI interface (don't bother with any WSGI interfaces on these servers yet) or by using them as a front end in front of Apache. Calls into the app get passed through (by proxy) to Apache+mod_wsgi and then nginx/lighttpd serve the static content directly.
Nginx has the added advantage of being able to serve content directly from memcached if you want to get that sophisticated. I've heard disparaging comments about lighttpd and it does seem to have some development problems, but there are certainly some big companies using it successfully.
Python stack
At the lowest level you can program to WSGI directly for the best performance. There are lots of helpful WSGI modules out there to help you in areas you don't want to develop yourself. At this level you'll probably want to pick third-party WSGI components to do things like URL resolving and HTTP request/response handling. A great request/response component is WebOb.
If you look at Pylons you can see their idea of "best-of-breed" WSGI components and a framework that makes it easier than Django to choose your own components like templating engine.
Django might be overkill but I don't think that's a really good argument against. Django makes the easy stuff easier. When you start to get into very complicated applications is where you really need to look at moving to lower level frameworks.
Look at Google App Engine. From their website:
Google App Engine lets you run your
web applications on Google's
infrastructure. App Engine
applications are easy to build, easy
to maintain, and easy to scale as your
traffic and data storage needs grow.
With App Engine, there are no servers
to maintain: You just upload your
application, and it's ready to serve
your users.
You can serve your app using a free
domain name on the appspot.com domain,
or use Google Apps to serve it from
your own domain. You can share your
application with the world, or limit
access to members of your
organization.
App Engine costs nothing to get
started. Sign up for a free account,
and you can develop and publish your
application for the world to see, at
no charge and with no obligation. A
free account can use up to 500MB of
persistent storage and enough CPU and
bandwidth for about 5 million page
views a month.
Best part of all: It includes Python support, including Django. Go to http://code.google.com/appengine/docs/whatisgoogleappengine.html
When you use mod_python on a threaded Apache server (the default on Windows), CherryPy runs in the same process as Apache. In that case, you almost certainly don't want CP to restart the process.
Solution: use mod_rewrite or mod_proxy so that CherryPy runs in its own process. Then you can autoreload to your heart's content. :)

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