librelist archives

Flask on a VPS

Flask on a VPS by JimG
- Re: [flask] Flask on a VPS by Simon Sapin
  - Re: [flask] Flask on a VPS by Simon Sapin
    - Re: [flask] Flask on a VPS by Armin Ronacher

Flask on a VPS

From:: JimG
Date:: 2010-07-31 @ 11:08

I did a blog post on getting a Flask App to work on a CENTOS VPS.


http://things-ive-learned-about-it.blogspot.com/2010/07/production-flask-app-on-centos-and.html

It's nothing more really than links to other documentation. Maybe someone
would find it useful - any feedback about if I've gone about anything the
wrong way.

One thing I'm uncomfortable with is running the application from the
public_html directory setup by the VPS? Is there a better place to put the
wsgi file and the application code? Perhaps under the home directory of the
user which the app runs as?

Thanks, Jim.

Re: [flask] Flask on a VPS

From:: Simon Sapin
Date:: 2010-07-31 @ 11:30

Hi

Le 31/07/2010 13:08, JimG a écrit :
> One thing I'm uncomfortable with is running the application from the 
> public_html directory setup by the VPS? Is there a better place to put 
> the wsgi file and the application code? Perhaps under the home 
> directory of the user which the app runs as?

Python code, templates and the .wsgi file do not have to (and maybe 
shouldn’t) be in a directory served by the web server. They can be 
anywhere. I like the home dir as it makes shorter rsync/git URLs.

Assuming Apache/mod_wsgi,

The .wsgi file need to be somewhere « allowed » by Apache :

	WSGIScriptAlias  /  /usr/local/www/wsgi-scripts/myapp.wsgi
	<Directory  /usr/local/www/wsgi-scripts>
		Order allow,deny
		Allow from all
	</Directory>


(stolen from mod_wsgi docs)

Then, there are several ways to serve static files
* Let Flask do it. (Not efficient, but Just Works©)
* Enable X-Send-File in Flask and use mod_xsendfile in Apache
* Use Apache Aliases, mod_rewrite, symbolic links or something else to 
make Apache serve them directly (most efficient, but require more 
configuration work)

Regards,
-- 
Simon Sapin

Re: [flask] Flask on a VPS

From:: Simon Sapin
Date:: 2010-07-31 @ 11:48

Le 31/07/2010 13:30, Simon Sapin a écrit :
> Then, there are several ways to serve static files
> * Let Flask do it. (Not efficient, but Just Works©)
>    

Actually, mod_wsgi does implement wsgi.file_wrapper to send static files 
more efficiently:
http://code.google.com/p/modwsgi/wiki/FileWrapperExtension

Flask and Werkzeug use it when available, so this solution is not as bad 
as moving megabytes of data around in pure Python.

Maybe I’ll do a proper benchmark later to compare all these solutions.

-- 
Simon Sapin

Re: [flask] Flask on a VPS

From:: Armin Ronacher
Date:: 2010-07-31 @ 16:33

Hi,

Unfortunately wsgi.cile_wrapper breaks if middlewares are part of the 
stack. Because of that x-sendfile is strongly recomended.

Regards,
Armin

(sent from a handheld device)

On 31.07.2010, at 13:48, Simon Sapin <simon.sapin@exyr.org> wrote:

> Le 31/07/2010 13:30, Simon Sapin a écrit :
>> Then, there are several ways to serve static files
>> * Let Flask do it. (Not efficient, but Just Works©)
>> 
> 
> Actually, mod_wsgi does implement wsgi.file_wrapper to send static files 
> more efficiently:
> http://code.google.com/p/modwsgi/wiki/FileWrapperExtension
> 
> Flask and Werkzeug use it when available, so this solution is not as bad 
> as moving megabytes of data around in pure Python.
> 
> Maybe I’ll do a proper benchmark later to compare all these solutions.
> 
> -- 
> Simon Sapin