WIP: What happens behind execution of an `import` statement?

Transcript

1. What happens when you do >> from spam import ham - Shivashis Padhi
2. Packages in Python
4. But how can we import a package from a different directory?
5. $PATH, and $PYTHONPATH
7. Regular and Namespace packages
8. The import system
9. sys.modules
10. Finders and loaders
11. Finders - examples • locate built-in modules • locate frozen modules • import path - imagine $PATH and $PYTHONPATH
12. Finders - function • If a finder is capable of handling import, it returns a module spec. • module spec contains module’s metadata i.e path, name, etc. The import machinery uses this spec to load modules later
13. find_spec
14. importing spam.ham
15. Import hooks and PEP 302
16. sys.path_hooks sys.meta_path
17. Loaders After spec object is returned from a finder, loaders are used to execute the module and store its reference in sys.modules
21. Code demonstration of an import hooks’ implementation.
22. importing submodules
23. What else can you do with import hooks? • full control after what happens after ‘import x’ • importing from ftp, https, authorization checks. • importing from a variety of storage, not just .py/.pyc
24. Thank you