mpe build

Build a PolicyDomain from a PolicyDomainReference with external Rego files.

Synopsis

mpe build --file <file> [--output <file>]

Description

The build command transforms a PolicyDomainReference YAML file into a complete PolicyDomain by reading external .rego files and inlining their contents.

This allows you to:

• Keep Rego code in separate .rego files for better editor support
• Use version control effectively on Rego files
• Maintain cleaner YAML files

Options

Option	Alias	Description	Required
--file	-f	PolicyDomainReference YAML file(s) to build	Yes
--output	-o	Output file path (single file only)	No

Examples

Build a Single File

mpe build -f my-domain-ref.yml
# Creates: my-domain-ref-built.yml

Build with Custom Output

mpe build -f my-domain-ref.yml -o my-domain.yml

Build Multiple Files

mpe build -f domain1-ref.yml -f domain2-ref.yml
# Creates: domain1-ref-built.yml, domain2-ref-built.yml

PolicyDomainReference Format

A PolicyDomainReference uses rego_filename instead of inline rego:

apiVersion: iamlite.manetu.io/v1alpha4
kind: PolicyDomainReference
metadata:
  name: my-domain
spec:
  policy-libraries:
    - mrn: "mrn:iam:library:utils"
      name: utils
      rego_filename: lib/utils.rego

  policies:
    - mrn: "mrn:iam:policy:main"
      name: main
      dependencies:
        - "mrn:iam:library:utils"
      rego_filename: policies/main.rego

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

Output Format

The build process:

1. Reads the PolicyDomainReference
2. For each rego_filename, reads the file content
3. Replaces rego_filename with rego containing the file content
4. Changes kind from PolicyDomainReference to PolicyDomain
5. Writes the result

Before (Reference)

policies:
  - mrn: "mrn:iam:policy:main"
    name: main
    rego_filename: policies/main.rego

After (Built)

policies:
  - mrn: "mrn:iam:policy:main"
    name: main
    rego: |
      package authz
      default allow = false
      # ... rest of main.rego content

Error Handling

Error	Cause	Solution
File not found	rego_filename path doesn't exist	Check file path is correct
Both specified	rego and rego_filename both present	Use only one
Invalid YAML	Malformed YAML syntax	Fix YAML syntax errors

Best Practices

1. Use relative paths: Keep .rego files relative to the YAML file
2. Organize by type: Separate directories for policies, libraries, mappers
3. Version control: Commit both reference and built files
4. CI integration: Build as part of your CI pipeline

Project Structure Example

my-policy-domain/
├── domain-ref.yml          # PolicyDomainReference
├── domain.yml              # Built PolicyDomain (generated)
├── lib/
│   ├── utils.rego
│   └── helpers.rego
├── policies/
│   ├── main.rego
│   └── admin.rego
└── mappers/
    └── http.rego