Home » Django » How to reload modules in django shell?

How to reload modules in django shell?

Posted by: admin November 30, 2017 Leave a comment

Questions:

I am working with Django and use Django shell all the time. The annoying part is that while the Django server reloads on code changes, the shell does not, so every time I make a change to a method I am testing, I need to quit the shell and restart it, re-import all the modules I need, reinitialize all the variables I need etc. While iPython history saves a lot of typing on this, this is still a pain. Is there a way to make django shell auto-reload, the same way django development server does?

I know about reload(), but I import a lot of models and generally use from app.models import * syntax, so reload() is not much help.

Answers:

I recommend using the django-extensions project like stated above by dongweiming. But instead of just ‘shell_plus’ management command, use:

manage.py shell_plus --notebook

This will open a IPython notebook on your web browser. Write your code there in a cell, your imports etc. and run it.

When you change your modules, just click the notebook menu item ‘Kernel->Restart’

There you go, your code is now using your modified modules.

Questions:
Answers:

look at the manage.py shell_plus command provided by the django-extensions project. It will load all your model files on shell startup. and autoreload your any modify but do not need exit, you can direct call there

Questions:
Answers:

It seems that the general consensus on this topic, is that python reload() sucks and there is no good way to do this.

Questions:
Answers:

My solution to it is I write the code and save to a file and then use:

python manage.py shell < test.py

So I can make the change, save and run that command again till I fix whatever I’m trying to fix.

Questions:
Answers:

I’d suggest use IPython autoreload extension.

./manage.py shell

In [1]: %load_ext autoreload
In [2]: %autoreload 2

And from now all imported modules would be refreshed before evaluate.

In [3]: from x import print_something
In [4]: print_something()
Out[4]: 'Something'

 # Do changes in print_something method in x.py file.

In [5]: print_something()
Out[5]: 'Something else'

Works also if something was imported before %load_ext autoreload command.

./manage.py shell
In [1]: from x import print_something
In [2]: print_something()
Out[2]: 'Something'

 # Do changes in print_something method in x.py file.

In [3]: %load_ext autoreload
In [4]: %autoreload 2
In [5]: print_something()
Out[5]: 'Something else'

There is possible also prevent some imports from refreshing with %aimport command and 3 autoreload strategies:

%autoreload

  • Reload all modules (except those excluded by %aimport) automatically
    now.

%autoreload 0

  • Disable automatic reloading.

%autoreload 1

  • Reload all modules imported with %aimport every time before executing
    the Python code typed.

%autoreload 2

  • Reload all modules (except those excluded by %aimport) every time
    before executing the Python code typed.

%aimport

  • List modules which are to be automatically imported or not to be
    imported.

%aimport foo

  • Import module ‘foo’ and mark it to be autoreloaded for %autoreload 1

%aimport -foo

  • Mark module ‘foo’ to not be autoreloaded.

This generally works good for my use, but there are some cavetas:

  • Replacing code objects does not always succeed: changing a @property in a class to an ordinary method or a method to a member variable can cause problems (but in old objects only).
  • Functions that are removed (eg. via monkey-patching) from a module before it is reloaded are not upgraded.
  • C extension modules cannot be reloaded, and so cannot be autoreloaded.
Questions:
Answers:

Reload() doesn’t work in Django shell without some tricks. You can check this thread na and my answer specifically:

How do you reload a Django model module using the interactive interpreter via "manage.py shell"?

Questions:
Answers:

My solution for this inconvenient follows. I am using IPython.

$ ./manage.py shell
> import myapp.models as mdls   # 'mdls' or whatever you want, but short...
> mdls.SomeModel.objects.get(pk=100)
> # At this point save some changes in the model
> reload(mdls)
> mdls.SomeModel.objects.get(pk=100)

Hope it helps. Of course it is for debug purposes.

Cheers.

Questions:
Answers:

Instead of running commands from the Django shell, you can set up a management command like so and rerun that each time.

Questions:
Answers:

Not exactly what you want, but I now tend to build myself management commands for testing and fiddling with things.

In the command you can set up a bunch of locals the way you want and afterwards drop into an interactive shell.

import code

class Command(BaseCommand):
  def handle(self, *args, **kwargs):
     foo = 'bar'
     code.interact(local=locals())

No reload, but an easy and less annoying way to interactively test django functionality.