Since Warehouse was built on top of an existing database (for legacy PyPI) and developers had to fit our ORM to the existing tables, some of the code in the ORM may not look like code from the SQLAlchemy documentation. There are some places where joins are done using name-based logic instead of a foreign key (but this may change in the future).
Warehouse also uses hybrid URL traversal and dispatch. Using factory classes, resources are provided directly to the views based on the URL pattern. This method of handling URLs may be unfamiliar to developers used to other web frameworks, such as Django or Flask. This article has a helpful discussion of the differences between URL dispatch and traversal in Pyramid.
Usage assumptions and concepts¶
Warehouse is specifically the codebase for the official Python Package Index, and thus focuses on architecture and features for PyPI and Test PyPI. People and groups who want to run their own package indexes usually use other tools, like devpi.
Warehouse serves four main classes of users:
People who are not logged in. This accounts for the majority of browser traffic and all API download traffic.
Owners/maintainers of one or more projects. This accounts for almost all writes. A user must create and use a PyPI account to maintain or own a project, and there is no particular functionality available to a logged-in user other than to manage projects they own/maintain. As of March 2018, PyPI had about 270,000 users, and Test PyPI had about 30,000 users.
PyPI application moderators. These users have a subset of the permissions of PyPI application administrators to assist in some routine administration tasks such as adding new trove classifiers, adjusting upload limits for distribution packages, and reviewing malware verdicts.
PyPI application administrators, e.g., Ee W. Durbin III, Dustin Ingram, and Donald Stufft, who can ban spam/malware projects, help users with account recovery, and so on. There are under ten such admins.
Since reads are much more common than writes (much more goes out than goes in), we try to cache as much as possible.
File and directory structure¶
The top-level directory of the Warehouse repo contains files including:
CONTRIBUTING.rst(the contribution guide)
requirements.txtfor the Warehouse virtual environment
Dockerfile: creates the Docker containers that Warehouse runs in
docker-compose.ymlfile configures Docker Compose
setup.cfgfor test configuration
Makefile: commands to spin up Docker Compose and the Docker containers, run the linter and other tests, etc.
files associated with Warehouse’s front end, e.g.,
Directories within the repository:
bin/ - high-level scripts for Docker, Travis, and Makefile commands
dev/ - assets for developer environment
tests/ - tests
warehouse/ - code in modules
accounts/ - user accounts
admin/ - application-administrator-specific
cache/ - caching
classifiers/ - frame trove classifiers
email/ - services for sending emails
i18n/ - internationalization
legacy/ - most of the read-only APIs implemented here
locales/ - internationalization
malware/ - automated malware checks
manage/ - logged-in user functionality (i.e., manage account & owned/maintained projects)
metrics/ - services for recording metrics
migrations/ - changes to the database schema
packaging/ - models
rate_limiting/ - rate limiting to prevent abuse
search/ - utilities for building and querying the search index
sitemap/ - site maps
templates/ - Jinja templates for web pages, emails, etc.
utils/ - various utilities Warehouse uses
Historical context & deprecations¶
For the history of Python packaging and distribution, see the PyPA history page.
From the early 2000s till April 2018, the legacy PyPI codebase, not Warehouse, powered PyPI. Warehouse deliberately does not provide some features that users may be used to from the legacy site, such as:
uploading to pythonhosted.com documentation hosting (discussion and plans)
key management: PyPI no longer has a UI for users to manage GPG or SSH public keys
uploading new releases via the web UI: instead, maintainers should use the command-line tool Twine
updating release descriptions via the web UI: instead, to update release metadata, you need to upload a new release (discussion)
OpenID and Google auth login are no longer supported.