fix(authz): fall back to body principal in _register_in_auth - #373

Summary

The whitelisted /agents/register path clears the middleware principal. The pod SDK ships the manifest-declared identity in the request body, but _register_in_auth was still reading only from the middleware and silently skipping ownership registration. This threads the body-supplied principal into the use case as a fallback, mirroring what #325 (cae5f94) already did for the route's check/grant fallback.

Symptom pre-fix: agent registration succeeds, no error logs, WARN Skipping authorization registration for agent: no creator resolvable fires at agents_use_case.py:83, and the agent has no owner tuple in agentex_permissions — invisible to the SGP UI listing.

Root cause

Bisected across three commits on the same code path:

cae5f94 recovered ownership grants for authenticated CLI/UI callers via the route layer, but the use case's register_resource call inside _register_in_auth was still reading only from the middleware. Result: every pod-based deploy since Jun 3 that lands on the whitelisted route lost its owner tuple.

What this change does

1. agentex/src/domain/use_cases/agents_use_case.py
   • _register_in_auth accepts an optional body_principal_context and uses it as fallback when the middleware principal isn't resolvable. Passes the resolved principal explicitly to register_resource(..., principal_context=...) so it doesn't silently default to the (None) middleware principal.
   • Extracts the dict-vs-object identity check into a private _has_resolvable_creator staticmethod (same shape as the one in agents.py:53).
   • register_agent accepts and forwards body_principal_context.
2. agentex/src/api/routes/agents.py
   • Route passes body_principal_context=request.principal_context when calling the use case, matching the precedence already applied to check/grant.
3. agentex/tests/integration/use_cases/test_agent_authz_dual_write.py
   • test_create_falls_back_to_body_principal_when_middleware_missing — covers the whitelisted pod path with a body-supplied service account.
   • test_middleware_principal_takes_precedence_over_body — regression guard confirming authenticated CLI/UI callers keep using the middleware identity.

What this change does NOT do

• register_build is intentionally left alone. That route isn't whitelisted, so the middleware principal is always set for legitimate callers — there's no trigger for the fallback there. Keeping the fix scoped to the actual regression.
• _has_resolvable_creator is now duplicated between agents.py (route) and agents_use_case.py (use case). De-duping into a shared util would be an unrelated refactor and would need to sit somewhere neutral (not in api/, since the domain shouldn't import from it). Happy to do that in a follow-up if a reviewer prefers.

Symptom (from Rocket beta)

The manifest for this agent declared a valid service account:

auth:
  principal:
    service_account_id: {{SERVICE_ACCOUNT_ID}}
    account_id: {{ACCOUNT_ID}}

The SDK correctly base64-encodes this into AUTH_PRINCIPAL_B64 and ships it in the register body's principal_context field (see scale-agentex-python/src/agentex/lib/utils/registration.py). The service was just not reading it in _register_in_auth.

Manual backfill of the agentex_permissions row (via POST /private/v5/agentex/permissions on egp-api-backend) restored visibility, confirming the SGP permissions row is what was missing.

Test plan

• New: test_create_falls_back_to_body_principal_when_middleware_missing
• New: test_middleware_principal_takes_precedence_over_body
• Existing 7 Mock-based tests in TestAgentRegisterOnCreate still pass locally (9/9 passed, 6 Docker-only tests deselected)
• Verify on beta: deploy a fresh agent from a Rocket manifest, confirm the agentex_permissions row is written automatically (no manual backfill required) and the agent shows up in the SGP UI listing

Greptile Summary

This PR fixes agent ownership registration on the whitelisted /agents/register path: _register_in_auth now accepts body_principal_context and falls back to it when the middleware principal is unresolvable, then forwards the resolved principal explicitly to register_resource and symmetrically to _safe_deregister on compensation.

• agents_use_case.py: _register_in_auth grows a body_principal_context fallback and returns (registered, resolved_principal) so caller sites can propagate the same principal to _safe_deregister; a new _has_resolvable_creator static method consolidates the identity check.
• agents.py: The route passes body_principal_context=request.principal_context to register_agent, mirroring the already-existing body fallback applied to check/grant.
• Tests: Three new mock-based tests cover the fallback, precedence, and duplicate-compensation scenarios on the whitelisted pod path.

sequenceDiagram
    participant Pod as Pod SDK (whitelisted path)
    participant Route as agents.py route
    participant UC as AgentsUseCase
    participant AuthSvc as AuthorizationService

    Pod->>Route: "POST /agents/register<br/>(body: principal_context = SA from manifest)"
    Note over Route: middleware principal = None
    Route->>Route: _has_resolvable_creator(None) → False
    Route->>Route: "principal_context = request.principal_context (body SA)"
    Route->>Route: "enforce_ownership = True"
    Route->>AuthSvc: "check(agent:*, create, principal_context=body_SA)"
    Route->>UC: "register_agent(..., body_principal_context=body_SA)"
    UC->>UC: "_register_in_auth(agent_id, body_principal_context=body_SA)"
    UC->>UC: middleware principal not resolvable → fallback to body_SA
    UC->>AuthSvc: "register_resource(agent, principal_context=body_SA)"
    AuthSvc-->>UC: ok
    UC->>UC: agent_repo.create(agent)
    alt DuplicateItemError
        UC->>AuthSvc: "deregister_resource(agent, principal_context=body_SA)"
        UC->>UC: adopt existing row
    end
    UC-->>Route: agent_entity
    Route->>AuthSvc: "grant(agent, principal_context=body_SA)"
    Route-->>Pod: RegisterAgentResponse

_{Reviews (6): Last reviewed commit: "Merge branch 'main' into akam/fix-authz-..." | Re-trigger Greptile}