django-zed-rebac 0.1.4

Drop-in REBAC engine for Django, SpiceDB-compatible, with a pure-Django LocalBackend.

django-zed-rebac

SpiceDB-compatible REBAC for any Django project. Drop in, declare your permission schema in a per-app permissions.zed file, and every queryset, save, and method call is gated against the effective user.

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Status: pre-alpha. The architecture is settled and reviewed; Tier-1 source has landed (LocalBackend, RebacMixin/manager, schema parser, rebac sync command, system checks). Caveat evaluation, SpiceDBBackend, and adapter modules are in flight. Nothing on PyPI yet. Track the milestones at docs/ARCHITECTURE.md § Roadmap.

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What it is

django-zed-rebac ports SpiceDB's relation-based access control model into Django. You author your permission schema as an SpiceDB-native .zed file alongside your app; the plugin loads it into DB tables on install with noupdate=True semantics that preserve admin edits, and admins tweak overrides through the admin UI (or your own GraphQL layer).

Two backends are interchangeable behind one Python API:

• LocalBackend — pure Django, evaluates permissions via recursive CTEs against a single Relationship table. Zero external infrastructure. Suitable up to ~10M relationships and depth ≤ 8.
• SpiceDBBackend — wraps the official authzed Python client. Connects to a SpiceDB cluster. Drop-in swap when LocalBackend is no longer enough — same Python API, no code changes, just REBAC_BACKEND = "spicedb" in settings.

Add the mixin to your model and Post.objects.all() returns only what the user can read. Add Model.objects.with_actor(actor) for explicit actor scoping in MCP servers, Celery tasks, GraphQL resolvers, and management commands — actor can be a Django User, a registered Agent, an agents/grant (agent-acting-on-behalf-of-user, shipped by your agents app), or anything @rebac_subject-registered. Typed shorthands as_user(user) and as_agent(agent, on_behalf_of=user) cover the common cases. The plugin itself only ships auth/user and auth/group schema (mapped onto django.contrib.auth); agents/agent, agents/grant, auth/apikey, and other subject types live in your own apps.

Quickstart

# settings.py
INSTALLED_APPS = [
    "django.contrib.auth",
    "django.contrib.contenttypes",
    # ...
    "rebac",
    "blog",
]

AUTHENTICATION_BACKENDS = [
    "rebac.backends.RebacBackend",
    "django.contrib.auth.backends.ModelBackend",
]

REBAC_BACKEND = "local"

// blog/permissions.zed
// @rebac_package: blog
// @rebac_package_version: 0.1.0
// @rebac_schema_revision: 1

definition blog/post {
    relation owner:  auth/user
    relation viewer: auth/user | auth/group#member | auth/user:*

    permission read   = owner + viewer
    permission write  = owner
    permission delete = owner
}

# blog/apps.py
class BlogConfig(AppConfig):
    name       = "blog"
    rebac_schema = "permissions.zed"   # relative to the app's package dir

# blog/models.py
from django.db import models
from rebac import RebacMixin

class Post(RebacMixin, models.Model):
    title  = models.CharField(max_length=200)
    body   = models.TextField()
    author = models.ForeignKey("auth.User", on_delete=models.CASCADE)

    class Meta:
        rebac_resource_type = "blog/post"

python manage.py migrate                  # creates Relationship + Schema* tables
python manage.py rebac sync           # loads permissions.zed into Schema* tables

# blog/views.py
def post_detail(request, pk):
    post = get_object_or_404(Post.objects.with_actor(request.user), pk=pk)
    return render(request, "post.html", {"post": post})

That's the end-to-end flow. The same Post.objects.with_actor(...) pattern works in DRF viewsets, Celery tasks, MCP tools, and GraphQL resolvers — the actor can be a Django User, an Agent, an agents/grant, or any registered subject. Typed shorthands as_user(request.user) and as_agent(agent, on_behalf_of=request.user) cover the common cases.

Documentation

Doc	When to read it
docs/ARCHITECTURE.md	You're integrating, contributing, or evaluating fit. Architecture, public API, the three storage tiers, settings, surface integrations, determinism, testing, roadmap.
docs/ZED.md	You're writing permission schemas. How to define permissions for users, groups, MCP tools, AI agents (Grant pattern), Celery tasks, hierarchical resources, time-bound access, arbitrary Python entities. Patterns library and anti-patterns.

Why use this

Problem	Existing options	What django-zed-rebac does
Per-object permissions in Django	django-guardian (per-object ACL via GenericFK; no JOIN propagation; no graph traversal)	True REBAC graph; SpiceDB-compatible; manager-level queryset scoping; cross-relation propagation.
Run SpiceDB-style permissions locally without infrastructure	None — SpiceDB itself is a Go binary that needs Postgres + a sidecar	LocalBackend: recursive CTE on a single Django table. Same API surface as SpiceDBBackend.
AI-agent authorization	Cedar (no graph traversal); Casbin (in-memory post-filter); Polar/Oso (deprecated 2023)	Native Authzed Grant pattern: an agent acting on behalf of a user receives the structural intersection of the user's grants and the agent's declared capabilities — enforced by the schema graph, not by app-layer ANDs.
Permission scoping outside HTTP	Manual if user.has_perm(...) everywhere	Model.objects.with_actor(actor) works in MCP servers, Celery tasks, cron, management commands, plain Python — anywhere. The actor is generic: Django User, Agent, agents/grant, auth/apikey, or any registered subject.
Strict-by-default (no silent leaks)	django-guardian returns all rows when nothing scopes; easy to forget	Querysets without an actor raise MissingActorError rather than returning everything. Bypass requires explicit .sudo(reason=...) and is logged.
Admin-editable policy with safe upgrades	django-guardian per-object ACL only; no rule overrides	Tier-2 SchemaOverride model: tighten / loosen / disable / extend a package-shipped baseline at runtime. noupdate=True semantics preserve admin edits across upgrades, mirroring Odoo's ir.model.data.

Highlights

• Three storage tiers, three editors. Tier 1 (structural, code-shipped .zed) → Tier 2 (override, admin-editable) → Tier 3 (relationships, runtime data). Clear ownership rule per tier — see docs/ARCHITECTURE.md § Conceptual model.
• Unified check API. check_access(op) / has_access(op) / accessible(op) — one entrypoint family, borrowed from Odoo 18's PR #179148 unification. No model-level vs record-level split at the call site.
• One mixin gates everything. Add RebacMixin to a model, declare Meta.rebac_resource_type, and queries / writes / method calls / FK reverse accessors are all permission-aware. No per-viewset wiring.
• with_actor(actor) ≠ sudo(reason=...). Distinct verbs for distinct intents. with_actor re-evaluates checks as that subject (user, agent, grant, apikey, …); sudo bypasses them with mandatory reason and audit-log entry. Originating uid preserved through bypass for audit. Sudo does NOT propagate through relationship traversal — every related read re-resolves against the carrying scope.
• Strict by default. A queryset without an actor scope raises rather than leaking. Bypass requires explicit .sudo(reason="cron.expire_drafts") and writes a structured audit event.
• Drop-in DRF integration. permission_classes = [RebacPermission] + filter_backends = [RebacFilterBackend]. Per-action permission map; customisable.
• Celery actor propagation built in. before_task_publish injects the actor into task headers; task_prerun restores it on the worker. Inside @shared_task, scoping happens transparently.
• MCP-aware. @rebac_mcp_tool decorator wraps FastMCP / official-SDK tool functions; resolves the actor from ctx.request_context.meta; checks before the tool body runs.
• Three-state checks. Like SpiceDB, check_access() returns HAS_PERMISSION, NO_PERMISSION, or CONDITIONAL_PERMISSION(missing=[...]) — the latter lists which caveat fields the caller must supply for a definitive answer.
• Type-checked. Ships py.typed. RebacManager[M] is Generic[M] — your IDE infers the right model class through the manager. mypy --strict and pyright both run on CI.
• noupdate=True upgrade safety. Admin schema edits are preserved across package upgrades. Destructive overwrite is an explicit --force-overwrite flag, never an implicit side effect of install vs upgrade. Engineers Odoo's -i footgun out.
• Deterministic build. python manage.py rebac sync --check is a CI gate that returns non-zero on schema drift, mirroring migrate --check.

Compatibility

Python	Django	Status
3.11 / 3.12 / 3.13 / 3.14	4.2 LTS	✅ planned
3.11 / 3.12 / 3.13 / 3.14	5.2 LTS	✅ planned
3.13 / 3.14	6.0	✅ planned

Versioning follows DjangoVer: <DJANGO_MAJOR>.<DJANGO_FEATURE>.<PACKAGE_VERSION>. Example: 6.0.1 means "works with Django 6.0, package iteration 1".

Database support: PostgreSQL 13+ (production target), MySQL 8+ (supported), SQLite (test/dev only — recursive CTE performance is not production-grade). The Relationship table ships with all required indexes in 0001_initial.py.

Comparison

Library	Per-object	Graph traversal	SpiceDB-compatible	AI-agent pattern	Maintained
django-zed-rebac	✅	✅	✅	✅ Grant pattern	(in development)
django-guardian	✅ (ACL via GenericFK)	❌	❌	❌	✅
django-rules	❌ (predicate engine)	❌	❌	❌	✅
django-spicedb	proxy only	✅ (via SpiceDB)	✅	❌	❌ (early/inactive)
casbin-django-orm-adapter	✅ (ACL, in-memory)	partial	❌	❌	✅
django-oso	✅	✅	❌	❌	❌ (deprecated 2023)
django-rls (PostgreSQL RLS)	✅	DB-level only	❌	❌	✅
zanzipy	✅	✅	partial	❌	❌ (early/single-author)

django-zed-rebac is the first Django package targeting full SpiceDB schema-language compatibility AND a working in-process backend AND a first-class AI-agent pattern AND admin-editable policy with safe upgrades — none of the others combine all four.

Backends in detail

┌─ Your application ──────────────────────────────────────────────┐
│   RebacMixin / RebacPermission / @rebac_resource / @rebac_mcp_tool   │
│                            │                                      │
│            ┌───────────────▼──────────────────┐                  │
│            │  rebac.backends.Backend (ABC)   │                  │
│            │   check_access  has_access        │                  │
│            │   accessible    lookup_subjects   │                  │
│            └───────────────┬──────────────────┘                  │
│              ┌─────────────┴────────────┐                        │
│              │                          │                        │
│   ┌──────────▼──────────┐   ┌───────────▼───────────┐           │
│   │  LocalBackend       │   │  SpiceDBBackend        │           │
│   │  recursive CTE +    │   │  authzed.api.v1.Client │           │
│   │  cel-python caveats │   │  → gRPC to spicedb     │           │
│   └─────────────────────┘   └────────────────────────┘           │
└──────────────────────────────────────────────────────────────────┘

Both backends are line-for-line API-compatible. The migration path is well-defined: prove your schema in LocalBackend first, then flip REBAC_BACKEND = "spicedb" and point at a SpiceDB cluster when scale or graph depth demands it. Persisted consistency tokens (Zookies) are not portable across the swap; this is the only operational consideration documented prominently in ARCHITECTURE.md § Migration safety.

What django-zed-rebac is NOT

• Not a User model. Use django.contrib.auth.models.User or any swappable AUTH_USER_MODEL.
• Not an authentication system. Use django-allauth, dj-rest-auth, simple-jwt, or your own.
• Not a session manager. Django's session middleware is fine.
• Not a multi-tenant database router. Use django-tenants or django-organizations. django-zed-rebac is orthogonal — it works inside whatever tenant scope the project provides. (For soft tenancy in a single DB, see REBAC_TYPE_PREFIX in ARCHITECTURE.md.)
• Not a GraphQL admin layer. A future django-zed-rebac-admin package may add one; v1 ships a Django admin form for SchemaOverride. Higher-level frameworks may layer their own admin surfaces on top.
• Not a policy DSL like Polar or Cedar. The schema language is SpiceDB's .zed, REBAC-first. ABAC fragments are expressed via caveats.

Status & roadmap

This is a pre-alpha package. The architecture is settled (see docs/ARCHITECTURE.md) but no PyPI release exists yet. Milestones:

• 0.1 — LocalBackend MVP, schema parser + sync command, RebacMixin, system checks, sync/check commands.
• 0.2 — Caveats + expiration support.
• 0.3 — Celery propagation + ActorMiddleware.
• 0.4 — Override layer (SchemaOverride + admin + effective_expr composition).
• 0.5 — SpiceDBBackend via authzed-py.
• 0.6 — MCP / GraphQL adapters.
• 1.0 — Stable release with full docs and CI matrix green.

Track the full plan in docs/ARCHITECTURE.md § Roadmap.

Contributing

Once the package lands on PyPI, contribution guidelines will live at CONTRIBUTING.md. For now, design feedback is welcome via GitHub issues — schema-language proposals, missing scenarios, integration-surface concerns, anything in ARCHITECTURE.md § Open questions you'd push back on.

License

Apache-2.0 (planned, matches authzed-py, cel-python, and spicedb itself).

Acknowledgments

django-zed-rebac is a faithful Django port of the model described in Google's Zanzibar paper and as implemented by SpiceDB. The schema language and API surface mirror SpiceDB's conventions exactly. The Grant pattern for AI-agent authorization is from Authzed's Secure AI Agents tutorial. The unified check API (check_access / has_access / accessible) is borrowed from Odoo 18 PR #179148. The noupdate=True upgrade-safety semantic is borrowed from Odoo's ir.model.data. Caveat evaluation in LocalBackend uses cel-python.