*.sentrie

The *.sentrie files contain the core policy definitions and shape definitions written in the Sentrie language. These files form the heart of your policy system, defining rules, shapes, and other constructs that control business logic and data validation.

Program Structure

A program file consists of:

• Namespace declaration (required)
• Top-level declarations (policies, shapes, shape exports)
  • Shape declaration (optional)
  • Shape export (optional)
  • Policy declaration (required)
• Comments (anywhere)

A program file can contain:

• Only one namespace.
• Multiple policy declarations.
• Multiple shape declarations.
• Multiple shape exports.

namespace com/example/myapp

-- This is a comment
-- For multiline comments,
-- each
-- line must start with "--"
--

shape User {
  -- shape definition
}

shape Invoice {
  -- shape definition
}

-- export shapes to allow visibility to other namespaces
export shape User
export shape Invoice

policy auth {
  -- policy content
}

policy user {
  -- policy content
}

policy billing {
  -- policy content
}

Policy structure

A policy statement is a container for related declarations in this order (comments allowed between lines). See Policy metadata for syntax, validation, and how metadata is indexed.

• optional metadata (title, description, version, repeatable tag)
• optional facts (all fact before any use)
• optional use imports
• body: let, rule, export, and policy-local shape declarations

namespace com/example/myauth

shape User {
  -- shape definition
}

policy auth {
  title "Authentication"
  description "Password and age checks for sign-in."
  version "1.0.0"
  tag "pack" = "myauth"
  tag "surface" = "sign_in"

  fact user: User
  fact passwordInput: string
  fact userAge: number

  use { calculateAge } from "./utils.ts" as utils
  use { hash } from @sentrie/crypto -- will alias to crypto by default

  let isPasswordValid = crypto.md5(passwordInput) == user.passwordHash
  let calculatedUserAge = utils.calculateAge(user.birthDate)

  rule myrule = default false {
    yield
      isPasswordValid
      and
      userAge == calculatedUserAge
  }

  -- export the decision of this rule so that it can be used by other policies and the runtime can execute it
  export decision of myrule
}

File Organization

Flexible placement:

• Can be located anywhere within the policy pack directory - or sub directories
• No required directory structure or naming conventions - organization is defined by namespaces
• Organize files based on your team’s preferences and project needs
• Group related policies together for better maintainability

Best practices:

• Use descriptive policy names that reflect their purpose
• Group related policies in namespaces - refer to Namespaces
• Keep individual policies focused on specific domains or features
• Consider using consistent naming patterns across your team

Declaration Types

Policy declarations:

• Business logic for different resources
• Conditional policies based on user attributes
• Time-based or context-aware rules

Shape definitions:

• Data validation schemas and shapes
• Input/output type definitions
• Structure validation for API requests

Namespace declarations:

• Logical grouping of related policies and shapes
• Hierarchical organization of rules
• Scoping and isolation of policy logic
• Import/export management

Language Features

Declarative syntax:

• Clean, readable policy definitions
• Focus on what, not how - business rules, not implementation details
• Easy to review and audit
• Natural language-like expressions (user.role is "admin")

Integration capabilities:

• Reference TypeScript modules for complex logic
• Call external functions and APIs (using use statements)
• Access runtime data and context