Namespace

The polymorphic root of every URL in GitLab. Every project lives under a namespace; every group is a namespace; every user has a namespace.

Source

app/models/namespace.rb plus subclasses:

• Namespaces::UserNamespace — personal namespace (one per user).
• Group — a group namespace (type = 'Group' in single-table inheritance).
• ProjectNamespace — synthetic namespace per project (used for routing & cross-cutting features).

app/models/namespaces/ and app/services/namespaces/ extend the base.

Why so polymorphic

A "namespace" is anything that can own projects, sub-resources, and a Git path:

• A user owns their personal namespace.
• A group owns nested groups and projects.
• A project owns a synthetic project namespace.

Routing uses a single namespaces.path column to assemble URLs without per-type lookups. This is why /gitlab-org/gitlab is a path and Namespaces::Path parses it.

Hierarchy

namespaces.parent_id builds a tree. Namespace#self_and_descendants, #self_and_ancestors, and Postgres recursive CTEs handle the tree (lib/gitlab/sql/recursive_cte.rb).

Settings

namespace_settings (a 1:1 settings table) holds:

• Default branch protection.
• Membership lock (group-only).
• Custom roles enabled (EE).
• Many feature toggles.

Aggregations

namespace_statistics rolls up counts (projects, storage, etc.) and is updated by Sidekiq workers when child resources change.

Storage

Namespaces have storage size and limit columns. Namespaces::Storage::* services enforce limits and produce notifications.

Related

• Project, Group, User.
• Cells — namespaces are organization-scoped.