03_src_layout.md

A full package includes a documentation, an installer, tests, a licence file, a README.md file... To add all these files in an orderly manner, we will modify the tree structure to use the src layout.

From a terminal window inside the WORKDIR/calculator directory:

• Create the src/calculator directory (mkdir -p src/calculator)
• Move the source code inside (mv *.py src/calculator)
• Remove the __pycache__ directory (rm -rf __pycache__)

Import is now broken (from the other terminal window), but now that we have a true package, we can install it; we just need to inform pip how install it.

• Create a file name pyproject.toml with the following content (choose a unique project name that won't clash with a serious package name):

  [build-system]
  requires = ["setuptools"]
  build-backend = "setuptools.build_meta"
  
  [project]
  name = "my_tuto_calculator_XXXX"
  authors = [
      {name = "Firstname Lastname", email = "firstname.lastname@domain.x"},
  ]
  description = "Extreme calculator"
  version = '0.0.0'
  

  In a normal use case, your project name is the same as the directory created in the src directory (calculator). Here we choose a different name to allow every one to push the same package on PyPI.
• In WORKDIR, create a virtual environment and activate it (python3 -m venv calcenv; . calcenv/bin/activate)
• From WORKDIR/calculator, install the package with pip install -e .

You can now import again your package with python3 -c "import calculator.basics".

And you can even test it: python3 -c "from calculator.basics import Calculator; c = Calculator(); print(c.add(4, 5)).

The result is false, we can update the source code in src/calculator/basics.py and run again the test. The important point is to note that we don't need to install the package again. With the -e (editable) option, you can edit and test rapidly your source code.

Git stuff:

• git status
• echo '*.egg-info' >> .gitignore
• git add src .gitignore *.py pyproject.toml
• git commit
• and because we set a version number, we can add an annotated tag with git tag -a

README and LICENCE files will be added in the next step.