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Mappers Schema

Definition

spec:
  mappers:
    - name: string          # Required: Human-readable name
      selector: []          # Required: Regex patterns to match
      rego: string          # Required: Rego code (or rego_filename)
      rego_filename: string # Alternative: External file path

Fields

Field	Type	Required	Description
name	string	Yes	Human-readable name
selector	array	Yes	List of regex patterns
rego	string	See below	Inline Rego code
rego_filename	string	See below	Path to external .rego file

Rego Code Fields

The rego and rego_filename fields specify where the Rego code comes from:

Document Kind	rego	rego_filename
PolicyDomain	Required	Not supported
PolicyDomainReference	Optional	Optional

For PolicyDomainReference, you must provide either rego (inline) or rego_filename (external file), but not both. Using rego_filename is recommended for development as it enables IDE syntax highlighting and cleaner version-control diffs.

See PolicyDomain vs PolicyDomainReference for more details.

Rego Requirements

Mappers must:

• Declare package mapper
• Export a porc variable with the PORC structure

package mapper

porc := {
    "principal": { ... },
    "operation": "...",
    "resource": { ... },
    "context": { ... }
}

Selectors

Selectors match against infrastructure identifiers (e.g., service account names, SPIFFE IDs). First match wins.

Examples

Basic Mapper

mappers:
  - name: default
    selector:
      - ".*"
    rego: |
      package mapper

      porc := {
          "principal": input.claims,
          "operation": input.operation,
          "resource": input.resource,
          "context": input
      }

Envoy HTTP Mapper

mappers:
  - name: http-mapper
    selector:
      - ".*"
    rego: |
      package mapper
      import rego.v1

      default claims := {}

      get_default(obj, key, fallback) := obj[key] if obj[key]
      get_default(obj, key, fallback) := fallback if not obj[key]

      method := lower(get_default(input.request.http, "method", "GET"))
      path := get_default(input.request.http, "path", "/")
      headers := get_default(input.request.http, "headers", {})

      # Extract service from SPIFFE ID
      dest := split(input.destination.principal, "/")
      service := dest[count(dest) - 1]

      # Extract JWT
      auth := headers.authorization
      token := split(auth, "Bearer ")[1] if auth
      claims := io.jwt.decode(token)[1] if token

      porc := {
          "principal": claims,
          "operation": sprintf("%s:http:%s", [service, method]),
          "resource": sprintf("mrn:http:%s%s", [service, path]),
          "context": input
      }

The PolicyEngine's Resource Resolution enriches MRN strings with metadata at evaluation time. Use the Fully Qualified Descriptor format only when the PEP has context the backend cannot determine.

Service-Specific Mappers

mappers:
  # Frontend service mapper
  - name: frontend
    selector:
      - ".*frontend.*"
    rego: |
      package mapper
      # Frontend-specific logic...

  # API service mapper
  - name: api
    selector:
      - ".*api-server.*"
    rego: |
      package mapper
      # API-specific logic...

  # Default fallback
  - name: default
    selector:
      - ".*"
    rego: |
      package mapper
      # Default logic...

Using External File

# In PolicyDomainReference
mappers:
  - name: http-mapper
    selector:
      - ".*"
    rego_filename: mappers/http.rego