Improvement: Adding component modules to environment

[Louis Amon]

Say you want to develop and distribute a plugin, and that this plugin relies on a third-party module or package.

For the example, we'll say the third-party is matplotlib.

In order to distribute your plugin, you'd need give instructions so that your plugin's users install matplotlib either in their environment or in the site-package folder of their web2py installation.

One way to avoid the hassle is to install matplotlib in the modules folder of your application. The custom_import function of gluon should do the rest of the work. Great.

Now what if you develop a big application that relies on 4 plugins that each rely on 6 third-parties ?

Should you install all 24 third-parties in your module folder ?

Wouldn't it become quite a mess ?

Here are suggestions to handling this issue :

• Option 1:
  
  Modify the custom_import function so that it could add subdirectories of the modules folder that are plugin components (for instance all file paths that start with 'APP_NAME/modules/PLUGIN_NAME')
  
  Adding a plugin's module folder to the environment could be optional, just like running a plugin's models is optional and possible via the 'models_to_run' variable.
  
  
• Option 2:
  
  Implementing pip inside web2py to manage plugin requirements upon install.
  This way, a plugin's installation would automatically trigger the installation of required third-parties into the site-package folder.
  

In my opinion both solutions could be interesting and complementary.

Feel free to contribute with your own opinion !