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OPA Gatekeeper Library

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A community-owned library of policies for the OPA Gatekeeper project.

Usage

kustomize

You can use kustomize to install some or all of the templates alongside your own contraints.

First, create a kustomization.yaml file:

apiVersion: kustomize.config.k8s.io/v1beta1
kind: Kustomization
resources:
- github.com/open-policy-agent/gatekeeper-library/library
# You can optionally install a subset by specifying a subfolder, or specify a commit SHA
# - github.com/open-policy-agent/gatekeeper-library/library/pod-security-policy?ref=0c82f402fb3594097a90d15215ae223267f5b955
- constraints.yaml

Then define your constraints in a file called constraints.yaml in the same directory. Example constraints can be found in the "samples" folders.

You can install everything with kustomize build . | kubectl apply -f -.

More information can be found in the kustomization documentation.

kubectl

Instead of using kustomize, you can directly apply the template.yaml and constraint.yaml provided in each directory under library/

For example

cd library/general/httpsonly/
kubectl apply -f template.yaml
kubectl apply -f samples/ingress-https-only/constraint.yaml
kubectl apply -f library/general/httpsonly/sync.yaml # optional: when GK is running with OPA cache

Testing

The suite.yaml files define test cases for each ConstraintTemplate in the library. Changes to gatekeeper-library ConstraintTemplates may be tested with the gator CLI:

gatekeeper-library$ gator verify ./...

The gator CLI may be downloaded from the Gatekeeper releases page.

How to contribute to the library

New policy

If you have a policy you would like to contribute, please submit a pull request. Each new policy should contain:

  • A constraint template named src/<policy-name>/constraint.tmpl with a description annotation and the parameter structure, if any, defined in spec.crd.spec.validation.openAPIV3Schema. The template is rendered using gomplate.
  • One or more sample constraints, each with an example of an allowed (example_allowed.yaml) and disallowed (example_disallowed.yaml) resource under library/<policy-name>/samples/<policy-name>
  • kustomization.yaml and suite.yaml under library/<policy-name>
  • The rego source, as src.rego and unit tests as src_test.rego in the corresponding subdirectory under src/<policy-name>
  • Versioning has been introduced for Gatekeeper Library policies. Please make sure to add or bump the version of the policy as per the guidelines in the src/<policy-name>/constraint.tmpl annotation.
    • Major version bump required: Whenever there is a breaking change in the policy e.g. updating template Kind, parameter schema, or any other breaking changes
    • Minor version bump required: Whenever there is a backward compatible change in the policy e.g. adding a parameter, updating Rego logic
    • Patch version bump required: Whenever there is a simple backward compatible change in the policy, e.g. Simple Rego fix, updating policy metadata

Development

  • policy code and tests are maintained in src/<policy-name>/src.rego and src/<policy-name>/src_test.rego
  • make generate will generate library/<policy-name>/template.yaml from src/<policy-name>/src.rego using gomplate.
  • make generate-website-docs will generate the markdown files required for the website.
  • make generate-artifacthub-artifacts will generate or update the artifact hub packages and associated artifacthub-pkg.yml file under /artifacthub directory.
  • run all tests with ./test.sh
  • run single test with opa test src/<folder>/src.rego src/<folder>/src_test.rego --verbose
  • print results with trace(sprintf("%v", [thing]))