Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > comp.lang.python > #61529 > unrolled thread

load_module for import entire package

Back to article view | Back to comp.lang.python

Contents

  load_module for import entire package Sergey <sh0375@gmail.com> - 2013-12-10 23:28 -0800
    Re: load_module for import entire package Dave Angel <davea@davea.name> - 2013-12-11 10:05 -0500
    Re: load_module for import entire package alex23 <wuwei23@gmail.com> - 2013-12-12 16:58 +1000
      Re: load_module for import entire package Sergey <sh0375@gmail.com> - 2013-12-12 23:09 -0800

#61529 — load_module for import entire package

Hi,
I need to import package and instantiate a class, defined in one of modules, located in package.

Package is located in folder "tmp". basedir - path to running python script.

I'm doing it so:

import imp

def load_package_strict(p_package_name, p_package_path):
    f, filename, description = imp.find_module(p_package_name, [p_package_path])
    try:
        result = imp.load_module(p_package_name, f, filename, description)
    finally:
        if f: f.close
    return result

def get_obj():
  pkg = load_package_strict("tmp", basedir)
  from tmp import main
  return main.TTT()

It is working, but if package code changes on disc at runtime and I call get_obj again, it returns instance of class, loaded for the first time previously. 

How to replace line "from tmp import main" by getting properties of pkg?

Regards,
Sergey

[toc] | [next] | [standalone]

#61580

On Tue, 10 Dec 2013 23:28:31 -0800 (PST), Sergey <sh0375@gmail.com> 
wrote:
> def get_obj():
>   pkg = load_package_strict("tmp", basedir)
>   from tmp import main
>   return main.TTT()


> It is working, but if package code changes on disc at runtime and I 
call get_obj again, it returns instance of class, loaded for the 
first time previously. 

That's how import works.  Once something has been imported,  the 
module information is cached. There are three ways to defeat that, 
but they're all risky. 



> How to replace line "from tmp import main" by getting properties of 
pkg?

No clue what you mean by that.

-- 
DaveA

[toc] | [prev] | [next] | [standalone]

#61671

On 11/12/2013 5:28 PM, Sergey wrote:
> def get_obj():
>    pkg = load_package_strict("tmp", basedir)
>    from tmp import main
>    return main.TTT()
>
> It is working, but if package code changes on disc at runtime and I call get_obj again, it returns instance of class, loaded for the first time previously.
>
> How to replace line "from tmp import main" by getting properties of pkg?

Your `load_package_strict` function loads the `tmp` module and binds it 
to the name `pkg`. You then use a regular import to load `tmp.main`, 
which is _cached_; all subsequent occurrences reuse the initially 
imported value.

This should work:

     def get_obj():
        tmp = load_package_strict("tmp", basedir)
        return tmp.main.TTT()

[toc] | [prev] | [next] | [standalone]

#61799

> This should work:
>      def get_obj():
>         tmp = load_package_strict("tmp", basedir)
>         return tmp.main.TTT()
Thank you:)
I can only mention that it is working only if __init__.py of pkg contains line: import main

To avoid modules caching I copy package to the new folder with another name and import it using this new name.

    tmp_pkg = "t" + str(randint(10000,100000000)) + '_' + time.strftime("%Y%m%d%H%M%S", time.localtime())
    shutil.copytree(pkg_dir, basedir + '/x/' + dir_name + '/' + tmp_pkg)

    pkg = load_package_strict(tmp_pkg, basedir + '/x/' + dir_name)
    result = pkg.main.TTT()
What is the risk of this method? What are 3 methods of doing the same?

--
Sergey

[toc] | [prev] | [standalone]

Back to top | Article view | comp.lang.python

csiph-web