Glossary

Repository

A collection of packages from a single source. An example of repository might be the packages already installed on the system, or a set of available packages from a package server.

Pool

A collection of multiple Repositories. The pool provides an interface for querying repositories for packages that satisfy Requirements.

Policy

A strategy for proposing the next package to try when the solver must make an assumption.

Package

In the object hierarchy, a “package” refers to a PackageMetadata instance. This describes a package, its dependencies “install_requires” and the packages with which it conflicts.

Colloquially, this refers to any kind of software distribution we might be trying to manage.

Request

The operations that we wish to apply to the collection of packages. This might include installing a new package, removing a package, or upgrading all installed packages.

Requirement

An object representation of a package range string, such as numpy > 1.8.2-2 or pip ^= 8.0.1. These are created from dependency information attached to PackageMetadata and passed to the Pool to query the available packages.