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Creating a Policy

Policies are authored in a declarative language called Rego. You can get started quickly by using a template.

Templates​

To list the available templates, use the policy templates list command:

policy templates list

Fetching templates .

  NAME             KIND    DESCRIPTION
  github           cicd    GitHub policy CI/CD template.
  gitlab           cicd    GitLab policy CI/CD template.
  policy-template  policy  Minimal policy template.

Applying a policy template​

To create a new policy, use the policy templates apply command:

policy templates apply policy-template

Processing template 'policy-template' .

Generating files

The template 'policy-template' was created successfully.

This will generate a minimal "hello world" policy.

tree -a .
.
├── README.md
└── src
    ├── .manifest
    └── policies
        └── hello-rego.rego

2 directories, 3 files

You can create a git repository for these files by using git init.

Adding a CI template​

To add GitHub or GitLab CI to the repository, apply a CI template. Note that the defaults are supplied if you've already done a policy login to log in to a registry, and made it your default policy registry.

policy templates apply github

Processing template 'github' .

  #  SERVER
  1  ghcr.io

> Select server#: 1

> server (ghcr.io):

> user (ogazitt):

> secret name (TOKEN):

> org/repo: ogazitt/policy-template

Generating files .

The template 'github' was created successfully.

This command generates a GitHub workflow to build, tag, and push a policy image based on a new tag event that is pushed to GitHub.

tree .github
.github
├── config.yaml
└── workflows
    └── build-release-policy.yaml

1 directory, 2 files

The .github/config.yaml file contains the parameters to the workflow:

server: ghcr.io
username: ogazitt
repo: ogazitt/policy-template

The secret name that was provided (by default, TOKEN) refers to a GitHub secret that contains a key (e.g. a PAT with the correct scopes) to push the built, tagged image to the policy registry.

For example, for ghcr.io, the PAT needs to have the repo and write:packages scopes.

For the Aserto Policy Registry, this should be the API key that can be found in the Console under the Aserto Policy Registry connection.

Automated policy-as-code workflow​

You now have a policy-as-code workflow - simply make changes in the policy, commit and tag a release, push the tags, and your policy image will be built, tagged, and pushed to the registry you configured.

Manual workflow​

You can also use the policy CLI to manually build, tag and push the policy to a policy registry.