Policy as Code

PaC defines what the desired state of access control should be, not how to implement it. The policy engine, such as Open Policy Agent (OPA) using the Rego language, evaluates the declared rules against incoming API requests.

• Separates authorization logic from application code
• Policies become auditable, testable artifacts
• Example: A Rego rule stating allow { input.user.role == "data_scientist" } grants access only to users with that specific role

Storing policy definitions in a Git repository applies software development best practices to security. Every change to an access rule is tracked, reviewed, and approved through a standard pull request workflow.

• Full audit history of who changed which rule and when
• Enables rollback of misconfigured policies
• Integrates with CI/CD pipelines for automated testing before deployment

PaC enables unit testing of authorization rules just like application code. Frameworks allow engineers to assert that specific inputs produce expected allow/deny decisions.

• Rego test commands validate policy logic offline
• Prevents regressions when updating complex rule sets
• Example: test_allow_admin { allow with input as {"user": {"role": "admin"}} } verifies admin access is correctly granted

A single policy engine can serve as the centralized Policy Decision Point (PDP) for an entire model serving platform. Lightweight Policy Enforcement Points (PEPs) integrated into API gateways or sidecars offload decisions to the PDP.

• Consistent authorization across REST, gRPC, and Kafka interfaces
• Eliminates fragmented, hard-coded access logic in microservices
• Simplifies auditing by centralizing all access decision logs

PaC moves beyond coarse Role-Based Access Control (RBAC) to Attribute-Based Access Control (ABAC). Policies evaluate contextual attributes at query time, including:

• User identity, group membership, and clearance level
• Resource metadata like model version, data classification, or cost center
• Environmental context such as request time, geolocation, or network origin
• Example: Denying access to a production model endpoint outside business hours from an untrusted IP range

PaC fits natively into GitOps workflows. Policy updates are synchronized with infrastructure changes, ensuring security posture evolves alongside the model serving stack.

• Kubernetes admission controllers use PaC to validate resource configurations
• Terraform and Pulumi can enforce policy checks during infrastructure provisioning
• Ensures new model endpoints are deployed with mandatory security controls already in place

A component in a zero-trust architecture that intercepts every request to a protected inference endpoint. The PEP queries an external policy engine to determine if the request should be allowed, enforcing the decision without embedding authorization logic directly in the model server.

• Sits inline with inference traffic
• Delegates decisions to the policy decision point
• Enforces allow/deny outcomes at the API gateway level

A compact, URL-safe token format that transmits claims securely between parties. Policy as code rules frequently inspect JWT claims—such as scope, audience, and expiration—to make stateless authorization decisions for inference API calls.

• Self-contained, cryptographically signed assertions
• Supports custom claims for fine-grained access
• Enables stateless policy evaluation at the edge

An authorization model that restricts system access based on assigned roles. Policy as code formalizes RBAC rules into version-controlled files, mapping roles to permitted model actions and ensuring consistent enforcement across development, staging, and production environments.

• Maps organizational roles to permissions
• Simplifies permission audits via code review
• Eliminates ad-hoc access grants

A chronological, tamper-proof record of all access and query events stored in WORM-compliant storage. Policy as code ensures that every authorization decision is logged with the specific policy version that produced it, enabling non-repudiation and compliance reporting.

• Links each decision to a policy commit hash
• Supports forensic analysis of access patterns
• Required for SOC 2 and GDPR compliance