poetryはPythonのパッケージの依存関係を管理するためのツール。 https://github.com/python-poetry/poetry

以下はインストールログ。

$ /Applications/Python\ 3.9/Install\ Certificates.command
/Applications/Python\ 3.9/Install\ Certificates.command
 -- pip install --upgrade certifi
Collecting certifi
  Using cached certifi-2020.12.5-py2.py3-none-any.whl (147 kB)
Installing collected packages: certifi
Successfully installed certifi-2020.12.5
WARNING: You are using pip version 20.2.3; however, version 20.3.3 is available.
You should consider upgrading via the '/Library/Frameworks/Python.framework/Versions/3.9/bin/python3.9 -m pip install --upgrade pip' command.
 -- removing any existing file or link
 -- creating symlink to certifi certificate bundle
 -- setting permissions
 -- update complete
$ curl -sSL https://raw.githubusercontent.com/python-poetry/poetry/master/get-poetry.py | python3.9 
curl -sSL https://raw.githubusercontent.com/python-poetry/poetry/master/get-poetry.py | python3.9 
Retrieving Poetry metadata

# Welcome to Poetry!

This will download and install the latest version of Poetry,
a dependency and package manager for Python.

It will add the `poetry` command to Poetry's bin directory, located at:

$HOME/.poetry/bin

This path will then be added to your `PATH` environment variable by
modifying the profile files located at:

$HOME/.profile
$HOME/.bash_profile

You can uninstall at any time by executing this script with the --uninstall option,
and these changes will be reverted.

Installing version: 1.1.4
  - Downloading poetry-1.1.4-darwin.tar.gz (38.50MB)

Poetry (1.1.4) is installed now. Great!

To get started you need Poetry's bin directory ($HOME/.poetry/bin) in your `PATH`
environment variable. Next time you log in this will be done
automatically.

To configure your current shell run `source $HOME/.poetry/env`
Install Poetry

通常poetryはvenv自体を作成してくれるが、それが邪魔になる時がある。 例えばvenv環境を別のツール(例えばIDEやエディターの機能)で別途行っているようなときだ。 そういうケースではpoetryにvenvを新たに作成してほしくない。

そういうときは以下のコマンドを実行すると現在の環境でパッケージの操作を行ってくれる。

poetry config virtualenvs.create false --local

コマンドを実行するとpoetry.tomlというファイルに設定が書き込まれる。

[virtualenvs]
create = false
poetry.toml

開発時は環境によってこの設定は異なると思われるのでgitignoreしておいたほうが良いかもしれない。