Dependency specification Dependencies for a project can be specified in various forms, which depend on the type of the dependency and on the optional constraints that might be needed for it to be installed. Version constraints Caret requirements Caret requirements allow SemVer compatible updates to a specified version. An update is allowed if the new version number does not modify the left-most non-zero digit in the major, minor, patch grouping. For instance, if we previously ran poetry add requests@^2.

Managing dependencies Dependency groups Poetry provides a way to organize your dependencies by groups. For instance, you might have dependencies that are only needed to test your project or to build the documentation. To declare a new dependency group, use a tool.poetry.group.<group> section where <group> is the name of your dependency group (for instance, test): [tool.poetry.group.test] # This part can be left out [tool.poetry.group.test.dependencies] pytest = "^6.0.0" pytest-mock = "*" Note All dependencies must be compatible with each other across groups since they will be resolved regardless of whether they are required for installation or not (see Installing group dependencies).

Basic usage For the basic usage introduction we will be installing pendulum, a datetime library. If you have not yet installed Poetry, refer to the Introduction chapter. Project setup First, let’s create our new project, let’s call it poetry-demo: poetry new poetry-demo This will create the poetry-demo directory with the following content: poetry-demo ├── pyproject.toml ├── README.md ├── poetry_demo │ └── __init__.py └── tests └── __init__.py The pyproject.toml file is what is the most important here.

Introduction Poetry is a tool for dependency management and packaging in Python. It allows you to declare the libraries your project depends on and it will manage (install/update) them for you. Poetry offers a lockfile to ensure repeatable installs, and can build your project for distribution. System requirements Poetry requires Python 3.8+. It is multi-platform and the goal is to make it work equally well on Linux, macOS and Windows.

Configuration Poetry can be configured via the config command (see more about its usage here) or directly in the config.toml file that will be automatically created when you first run that command. This file can typically be found in one of the following directories: macOS: ~/Library/Application Support/pypoetry Windows: %APPDATA%\pypoetry For Unix, we follow the XDG spec and support $XDG_CONFIG_HOME. That means, by default ~/.config/pypoetry. Local configuration Poetry also provides the ability to have settings that are specific to a project by passing the --local option to the config command.

Managing environments Poetry makes project environment isolation one of its core features. What this means is that it will always work isolated from your global Python installation. To achieve this, it will first check if it’s currently running inside a virtual environment. If it is, it will use it directly without creating a new one. But if it’s not, it will use one that it has already created or create a brand new one for you.

Managing dependencies Dependency groups Poetry provides a way to organize your dependencies by groups. For instance, you might have dependencies that are only needed to test your project or to build the documentation. To declare a new dependency group, use a tool.poetry.group.<group> section where <group> is the name of your dependency group (for instance, test): [tool.poetry.group.test] # This part can be left out [tool.poetry.group.test.dependencies] pytest = "^6.0.0" pytest-mock = "*" Note All dependencies must be compatible with each other across groups since they will be resolved regardless of whether they are required for installation or not (see Installing group dependencies).

Dependency specification Dependencies for a project can be specified in various forms, which depend on the type of the dependency and on the optional constraints that might be needed for it to be installed. Version constraints Caret requirements Caret requirements allow SemVer compatible updates to a specified version. An update is allowed if the new version number does not modify the left-most non-zero digit in the major, minor, patch grouping. For instance, if we previously ran poetry add requests@^2.

Plugins Poetry supports using and building plugins if you wish to alter or expand Poetry’s functionality with your own. For example if your environment poses special requirements on the behaviour of Poetry which do not apply to the majority of its users or if you wish to accomplish something with Poetry in a way that is not desired by most users. In these cases you could consider creating a plugin to handle your specific logic.

Commands You’ve already learned how to use the command-line interface to do some things. This chapter documents all the available commands. To get help from the command-line, simply call poetry to see the complete list of commands, then --help combined with any of those can give you more information. Global options --verbose (-v|vv|vvv): Increase the verbosity of messages: “-v” for normal output, “-vv” for more verbose output and “-vvv” for debug.