8 ms·

Python Web Frameworks – Development Server

44 points by dabent 15y ago

bwooceli 15y ago
(posted to blog as well) would like to know more about the strengths/weaknesses of these development resources. For example, one of the things i love about the django dev server is that it "listens" to all the project dependencies and restarts when any file is saved (which has saved me from trying to understand why something I fixed didn't work and discovering that it's because the changes weren't .pyc'd)
- chrisguitarguy 15y ago
  Flask/Werkzeug does that as well, provided your app is in debug mode. For flask it's... app.run(debug=True) Or having `DEBUG = True` somewhere in your config object/file.
  - m_eiman 15y ago
    Same for CherryPy, more or less.
  - prolepunk 15y ago
    One thing about that though, Flask seems to monitor file changes in its project tree and reload whenever any of the files have changed, and with my OCD symptom of saving after every few dosen keystrokes, the reload script keps crashing on syntax errors taking the rest of the server with it.
- nas 15y ago
  I'm not a big fan of auto-restart. It's slow for the server to crawl over all files and check if re-load is needed. Having individual modules reload themselves without reloading the whole server is error prone (e.g. you could end up using an old class). With Quixote I have a Tkinter GUI that shows me the debug and access logs and lets me restart the DB or app server with a single click. When I'm ready to test I just right-click on that window and the app server restarts.
  - Tobu 15y ago
    If this matters — and the reload feature is for development, so I'm not sure the polling has a noticeable impact — an inotify implementation is also possible.
perfunctory 15y ago
That's not a bad overview, but what's the point? How one way is better than the other? Does it make any difference which development server to use?
- prolepunk 15y ago
  Although it's not stated, the point is that pretty much every framework that is not based on Twisted uses BaseHTTPServer which is known only to run in single-process mode, meaning that you should NEVER use it anywhere near production environment.
  - BarkMore 15y ago
    I am not sure what you mean by "single-process mode", but I am guessing that you are referring to the ability to serve more than one request at a time. If this is the issue, then BaseHTTPServer works just fine in production environments if a thread pool is used or if multiple instances of the application are run behind a reverse proxy.
    - prolepunk 15y ago
      Sorry I wasn't clear, I meant serving more than one request at a time, and apparently this is even possible without using multiple instances, use multiple inheritance with a threading mixin. This is not going to be properly concurent due to GIL limitations but it should be good enough -- http://blog.doughellmann.com/2007/12/pymotw-basehttpserver.html http://blog.doughellmann.com/2007/12/pymotw-basehttpserver.h... However this setup can lead to socket lockup (see picked answer) -- http://stackoverflow.com/questions/5693741/whats-difference-between-a-simple-webserver-and-apache-server http://stackoverflow.com/questions/5693741/whats-difference-...
      - BarkMore 15y ago
        I am not sure what you mean by "properly concurrent", but I am guessing that you are referring to the fact that Python code cannot use more than one core because of the GIL. This limitation also applies to Twisted applications. For high volume apps, it often makes sense to run multiple instances of the app behind a reverse proxy. That's the only way to make full use the CPU when running Python. What is "socket lockup"? The word "lockup" is nowhere to be found on the page you references.
danko 15y ago
What this article taught me is the mind-boggling plethora of Python web frameworks out there. I'm heavily into Django myself, and it does well enough that I'm curious as to the demand for the other frameworks. How many Python web frameworks do you really need in 2012?
- samlev 15y ago
  For me? Two. Django is good for getting a site/system up and running fast, so long as I'm not too concerned with specific implementation details (the users 'just work', etc.) Pyramid is good for a longer-term/more custom system where being easily able to modify (or choose) particular implementation details is important to me. It's not as fast to get a full-featured site off the ground, but the pieces glue together in a way that I really like. I think that there was a well known post many years ago about "glue" and "full stack" frameworks, comparing pylons (now pyramid) as the former, and django as the latter. #EDIT: Oh, and I used to do a bit of work with Zope/Plone, but that's pretty much what you'd consider to be the 'enterprisey' setup for python, and I wouldn't recommend it for most uses.
  - inovica 15y ago
    That mirrors exactly our experience. We have used Pyramid for three recent project and its awesome. It just takes a little longer, but its flexibility is impressive. We've just used it with Pure templates also, which I was very impressed with
- 7952 15y ago
  There is always a demand for something that feels and acts less monolithic.
- sontek 15y ago
  There can only be one! Pyramid
jamesgeck0 15y ago
The twisted.web server is nice because you can both develop on it and deploy it with minimal configuration. Using twisted.web.wsgi.WSGIResource, you can use it to serve normal WSGI sites, too. It's handy for running multiple sites on different ports. It doesn't automatically reload on file changes, but PyQuitter[1] can provide that functionality, so it's not a huge issue. 1. https://github.com/ludios/Pyquitter https://github.com/ludios/Pyquitter
nas 15y ago
FYI, Quixote (http://quixote.ca http://quixote.ca) provides a bunch of options too: python -m quixote.server.simple_server python -m quixote.server.medusa_server python -m quixote.server.twisted_server python -m quixote.server.fastcgi_server python -m quixote.server.scgi_server simple_server uses BaseHTTPServer and is thus single-threaded and blocking but works fine for development. I like FastCGI or SCGI with a dedicated webserver as a frontend for production.
jtchang 15y ago
Sometimes I have problems with runserver and IE. I forgot exactly why (probably multiple requests) but fixed it by using this: https://github.com/ashchristopher/django-concurrent-server https://github.com/ashchristopher/django-concurrent-server Really nice module.

44 points by dabent 15y ago

(posted to blog as well) would like to know more about the strengths/weaknesses of these development resources. For example, one of the things i love about the django dev server is that it "listens" to all the project dependencies and restarts when any file is saved (which has saved me from trying to understand why something I fixed didn't work and discovering that it's because the changes weren't .pyc'd)

chrisguitarguy 15y ago
Flask/Werkzeug does that as well, provided your app is in debug mode. For flask it's... app.run(debug=True) Or having `DEBUG = True` somewhere in your config object/file.
- m_eiman 15y ago
  Same for CherryPy, more or less.
- prolepunk 15y ago
  One thing about that though, Flask seems to monitor file changes in its project tree and reload whenever any of the files have changed, and with my OCD symptom of saving after every few dosen keystrokes, the reload script keps crashing on syntax errors taking the rest of the server with it.
nas 15y ago
I'm not a big fan of auto-restart. It's slow for the server to crawl over all files and check if re-load is needed. Having individual modules reload themselves without reloading the whole server is error prone (e.g. you could end up using an old class). With Quixote I have a Tkinter GUI that shows me the debug and access logs and lets me restart the DB or app server with a single click. When I'm ready to test I just right-click on that window and the app server restarts.
- Tobu 15y ago
  If this matters — and the reload feature is for development, so I'm not sure the polling has a noticeable impact — an inotify implementation is also possible.

perfunctory 15y ago

That's not a bad overview, but what's the point? How one way is better than the other? Does it make any difference which development server to use?

prolepunk 15y ago
Although it's not stated, the point is that pretty much every framework that is not based on Twisted uses BaseHTTPServer which is known only to run in single-process mode, meaning that you should NEVER use it anywhere near production environment.
- BarkMore 15y ago
  I am not sure what you mean by "single-process mode", but I am guessing that you are referring to the ability to serve more than one request at a time. If this is the issue, then BaseHTTPServer works just fine in production environments if a thread pool is used or if multiple instances of the application are run behind a reverse proxy.
  - prolepunk 15y ago
    Sorry I wasn't clear, I meant serving more than one request at a time, and apparently this is even possible without using multiple instances, use multiple inheritance with a threading mixin. This is not going to be properly concurent due to GIL limitations but it should be good enough -- http://blog.doughellmann.com/2007/12/pymotw-basehttpserver.html http://blog.doughellmann.com/2007/12/pymotw-basehttpserver.h... However this setup can lead to socket lockup (see picked answer) -- http://stackoverflow.com/questions/5693741/whats-difference-between-a-simple-webserver-and-apache-server http://stackoverflow.com/questions/5693741/whats-difference-...
    - BarkMore 15y ago
      I am not sure what you mean by "properly concurrent", but I am guessing that you are referring to the fact that Python code cannot use more than one core because of the GIL. This limitation also applies to Twisted applications. For high volume apps, it often makes sense to run multiple instances of the app behind a reverse proxy. That's the only way to make full use the CPU when running Python. What is "socket lockup"? The word "lockup" is nowhere to be found on the page you references.

danko 15y ago

What this article taught me is the mind-boggling plethora of Python web frameworks out there. I'm heavily into Django myself, and it does well enough that I'm curious as to the demand for the other frameworks. How many Python web frameworks do you really need in 2012?

samlev 15y ago
For me? Two. Django is good for getting a site/system up and running fast, so long as I'm not too concerned with specific implementation details (the users 'just work', etc.) Pyramid is good for a longer-term/more custom system where being easily able to modify (or choose) particular implementation details is important to me. It's not as fast to get a full-featured site off the ground, but the pieces glue together in a way that I really like. I think that there was a well known post many years ago about "glue" and "full stack" frameworks, comparing pylons (now pyramid) as the former, and django as the latter. #EDIT: Oh, and I used to do a bit of work with Zope/Plone, but that's pretty much what you'd consider to be the 'enterprisey' setup for python, and I wouldn't recommend it for most uses.
- inovica 15y ago
  That mirrors exactly our experience. We have used Pyramid for three recent project and its awesome. It just takes a little longer, but its flexibility is impressive. We've just used it with Pure templates also, which I was very impressed with
7952 15y ago
There is always a demand for something that feels and acts less monolithic.
sontek 15y ago
There can only be one! Pyramid

jamesgeck0 15y ago

The twisted.web server is nice because you can both develop on it and deploy it with minimal configuration. Using twisted.web.wsgi.WSGIResource, you can use it to serve normal WSGI sites, too. It's handy for running multiple sites on different ports. It doesn't automatically reload on file changes, but PyQuitter[1] can provide that functionality, so it's not a huge issue. 1. https://github.com/ludios/Pyquitter https://github.com/ludios/Pyquitter

nas 15y ago

FYI, Quixote (http://quixote.ca http://quixote.ca) provides a bunch of options too: python -m quixote.server.simple_server python -m quixote.server.medusa_server python -m quixote.server.twisted_server python -m quixote.server.fastcgi_server python -m quixote.server.scgi_server simple_server uses BaseHTTPServer and is thus single-threaded and blocking but works fine for development. I like FastCGI or SCGI with a dedicated webserver as a frontend for production.

jtchang 15y ago

Sometimes I have problems with runserver and IE. I forgot exactly why (probably multiple requests) but fixed it by using this: https://github.com/ashchristopher/django-concurrent-server https://github.com/ashchristopher/django-concurrent-server Really nice module.