nsimport 0.1.0

Load modules to different namespaces (not inject them into global namespace).

With creating individual namespaces for python import mechanism, we can use NsImporter to load modules without conflict.

All modules loaded by NsImporters will be added to NsImporter’s own namespace (access with self.sys), and sys.module contains no them.

So we can import our modules without conflict such as modules with same name, different packages versions or other situations we do not want loaded modules present in sys.modules.

• This library is modified from importlib of python3.8, but there are only 2 differences between nsimport and importlib:

  • __init__.py of importlib is edited to be nsimporter_internal.py by creating a class type to implement namespace initializing before being used to import modules. The class is initialized by set namespace’s sys to parameter sys passed to it.

  • new __init__.py for whole library.

APIs

All available defined APIs can be found in __init__.py and nsimporter_internal.py.

But it is disencouraged to directly use APIs except nsimport.get_NsImporter(path: list) which returns a new NsImporter initialized with a copied sys module.

If you know exactly what module sys do when interpreter imports modules, you can create your own namespace and pass it to nsimport.NsImporter(sys) and it will be use to initialize the importer.

Different NsImporters have different namespaces (if different sys modules are passed to it), so it is feasible to use 2 or more importer at the same time.

Example

>>> import nsimport
>>> importer = nsimport.get_NsImporter([])
>>> importer
<nsimport.nsimporter_internal.implib object at 0x7fae0568fdc0>
>>> importer.import_module('os')
<module 'os' from '/usr/local/lib/python3.8/os.py'>
>>> importer.import_module('codeop')
<module 'codeop' from '/usr/local/lib/python3.8/codeop.py'>
>>> 'codeop' in sys.modules
False
>>> 'codeop' in importer.sys.modules
True

Notice

For every NsImporter has its own namespace, all modules loaded by now loading module will be injected to NsImporter’s sys.modules but global sys.modules.

Only test on python3.8, and you can run script import_tests.py to check if the library works.

Details of implementation are in function nsimporter_internal.implib.__init__ which replaces sys module of namespaces of _bootstrap functions with its own sys.

Advance

Another implementation of namespace specific importer is in moduleimporter, and it provide more general apis, wrapper objects, and reflection mechanism for python modules.