{"title":"axju - python","link":[{"@attributes":{"href":"https:\/\/axju.de\/","rel":"alternate"}},{"@attributes":{"href":"https:\/\/axju.de\/feeds\/python.atom.xml","rel":"self"}}],"id":"https:\/\/axju.de\/","updated":"2021-04-26T20:15:00+02:00","subtitle":"Just coding stuff","entry":[{"title":"importlib.metadata","link":{"@attributes":{"href":"https:\/\/axju.de\/posts\/2021\/04\/importlibmetadata\/","rel":"alternate"}},"published":"2021-04-26T20:15:00+02:00","updated":"2021-04-26T20:15:00+02:00","author":{"name":"Axel Juraske"},"id":"tag:axju.de,2021-04-26:\/posts\/2021\/04\/importlibmetadata\/","summary":"

I didn't notice that pkg_resources was replaced by importlib.metadata from the standard library<\/p>\n","content":"

Module importlib.metadata<\/a> has been around since Python version 3.8. And that make pkg_resources<\/strong> some kind of deprecated.\nI personally uses pkg_resources<\/strong> on two places and didn't realize that it was out of date.<\/p>\n

    \n
  1. To load some entry point, if I build a pluggable package.<\/li>\n
  2. Get the version number at runtime, if I uses setuptools-scm.<\/li>\n<\/ol>\n

    Maybe in different places, but these two pop up in my head first.\nThere is also a package<\/a> that supplies backports of functionality for Python version smaller then 3.8<\/p>\n

    \n

    Load entry points<\/h2>\n

    The Python setup script provides entry points where objects can be assigned.\nIn your main package, you can search for specific entry points and load them.\nOther package can also defined this entry point, so your main package will load them too.\nIf you are interesting, I make a small video<\/a>. Unfortunately, this video uses the old pkg_resources<\/strong> module.<\/p>\n

    With importlib.metadata<\/strong>, the new one:<\/p>\n

    <\/span>>>><\/span> from<\/span> importlib.metadata<\/span> import<\/span> entry_points<\/span>\n>>><\/span> for<\/span> enp<\/span> in<\/span> entry_points<\/span>()[<\/span>'axju.commands'<\/span>]:<\/span>\n...<\/span>   print<\/span>(<\/span>enp<\/span>.<\/span>name<\/span>)<\/span>\n...<\/span>\ndjango<\/span>\ninfo<\/span>\nshow<\/span>\n<\/pre><\/div>\n
    The old one with pkg_resources<\/strong>:<\/p>\n
    <\/span>>>><\/span> from<\/span> pkg_resources<\/span> import<\/span> iter_entry_points<\/span>\n>>><\/span> for<\/span> enp<\/span> in<\/span> iter_entry_points<\/span>(<\/span>group<\/span>=<\/span>'axju.commands'<\/span>):<\/span>\n...<\/span>   print<\/span>(<\/span>enp<\/span>.<\/span>name<\/span>)<\/span>\n...<\/span>\ndjango<\/span>\ninfo<\/span>\nshow<\/span>\n<\/pre><\/div>\n<\/div>\n
    \n
    Retrieving package version at run time<\/h2>\n
    You can find this example on the readme file from setuptools-scm<\/strong>.<\/p>\n
    This is how you should do it, with importlib.metadata<\/strong>:<\/p>\n
    <\/span>from<\/span> importlib.metadata<\/span> import<\/span> version<\/span>,<\/span> PackageNotFoundError<\/span>\n\ntry<\/span>:<\/span>\n    __version__<\/span> =<\/span> version<\/span>(<\/span>"package-name"<\/span>)<\/span>\nexcept<\/span> PackageNotFoundError<\/span>:<\/span>\n    __version__<\/span> =<\/span> 'Unknown'<\/span>\n<\/pre><\/div>\n
    And you'd better avoid that:<\/p>\n
    <\/span>from<\/span> pkg_resources<\/span> import<\/span> get_distribution<\/span>,<\/span> DistributionNotFound<\/span>\n\ntry<\/span>:<\/span>\n    __version__<\/span> =<\/span> get_distribution<\/span>(<\/span>"package-name"<\/span>)<\/span>.<\/span>version<\/span>\nexcept<\/span> DistributionNotFound<\/span>:<\/span>\n    __version__<\/span> =<\/span> 'Unknown'<\/span>\n<\/pre><\/div>\n
    However, this does place a runtime dependency on setuptools<\/strong> and can add up\nto a few 100ms overhead for the package import time.<\/p>\n<\/div>\n
    \n
    Conclusion<\/h2>\n
    As you can see, these are not major changes to the source code.\nSo the problem are not the adjustments, but the fact you should read the release note.\nShame on me, I don't read them very often. I only came across this while researching for my video. But even then I did get it after the video it was published.<\/p>\n
    The biggest source for my video was the post<\/a> from Amir Rachum's Blog, which was written before the release of version 3.8. That's why he still used pkg_resources<\/strong>.<\/p>\n
    \n
    Memo to myself, read the release note<\/h3>\n<\/div>\n<\/div>\n","category":[{"@attributes":{"term":"python"}},{"@attributes":{"term":"python"}}]},{"title":"Python Pathlib","link":{"@attributes":{"href":"https:\/\/axju.de\/posts\/2021\/01\/python-pathlib\/","rel":"alternate"}},"published":"2021-01-29T20:15:00+01:00","updated":"2021-01-29T20:15:00+01:00","author":{"name":"Axel Juraske"},"id":"tag:axju.de,2021-01-29:\/posts\/2021\/01\/python-pathlib\/","summary":"
    I know the Pathlib is nothing new, but I only discovered in the new django default settings.<\/p>\n","content":"
    For a long time I ignore pathlib, but then came new django release with this in\nthe default settings.<\/p>\n
    <\/span>from<\/span> pathlib<\/span> import<\/span> Path<\/span>\n\n# Build paths inside the project like this: BASE_DIR \/ 'subdir'.<\/span>\nBASE_DIR<\/span> =<\/span> Path<\/span>(<\/span>__file__<\/span>)<\/span>.<\/span>resolve<\/span>()<\/span>.<\/span>parent<\/span>.<\/span>parent<\/span>\n<\/pre><\/div>\n
    I researched and found these links very helpful:<\/p>\n
    \n