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Overview

This feature allow operators to group related policies into one single entity that can be reused across the organization. With Policy Groups, materials and policies can be enforced in Chainloop contracts with little or no effort. For example, they might want to create a “SBOM quality” group with some SBOM-related policies. The policy groups can be defined this way: 
# sbom-quality.yaml
apiVersion: workflowcontract.chainloop.dev/v1
kind: PolicyGroup
metadata:
  name: sbom-quality
  description: This policy group applies a number of SBOM-related policies
  annotations:
    category: SBOM
spec:
  inputs:
    - name: bannedLicenses
      description: comma separated list of licenses to ban
      required: true
    - name: bannedComponents
      description: comma separated list of components to ban
      required: true
  policies:
    materials:
      - name: sbom
        type: SBOM_CYCLONEDX_JSON
        policies:
        - ref: sbom-banned-licenses
          with:
            licenses: {{ inputs.bannedLicenses }}
        - ref: sbom-banned-components
          with:
            components: {{ inputs.bannedComponents }}

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Using Policy Groups

This policy group could be applied to any contract: 
schemaVersion: v1
materials: []
policyGroups:
  - ref: file://groups/sbom-quality-group.yaml
    with:
      bannedComponents: log4j@2.14.1
      bannedLicenses: AGPL-1.0-only, AGPL-1.0-or-later, AGPL-3.0-only, AGPL-3.0-or-later
As we introduced earlier, policy groups define both materials and policies applied to them. Once they are included to a contract, they become part of the contract. From this point of view, they can be seen as subcontracts, as they can also be used to enforce materials to be present in the attestation. For example, after applying the above contract, doing an attestation push would fail until the required material is provided: 
$ chainloop att init --workflow mywf --project myproject
INF Attestation initialized! now you can check its status or add materials to it
┌────────────────┬──────────────────────────────────────┐
│ Initialized At │ 30 Dec 24 12:26 UTC                  │
├────────────────┼──────────────────────────────────────┤
│ Attestation ID │ a52f082c-ca4a-4952-bb07-fa9117c04a90 │
│ Organization   │ my-org                               │
│ Name           │ mywf                                 │
│ Project        │ myproject                            │
│ Version        │ v0.148.0 (prerelease)                │
│ Contract       │ myproject-mywf (revision 76)         │
└────────────────┴──────────────────────────────────────┘
┌────────────────────────────────┐
│ Materials                      │
├──────────┬─────────────────────┤
│ Name     │ sbom                │
│ Type     │ SBOM_CYCLONEDX_JSON │
│ Set      │ No                  │
│ Required │ Yes                 │
└──────────┴─────────────────────┘

$ chainloop att push
ERR some materials have not been crafted yet: sbom
exit status 1

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Policy group parameters

In the same way as policies, groups can accept arguments, which are specified in the inputs section. Then those inputs can be passed down to policies using interpolation. In the example above, bannedComponents input parameter (which is mandatory) is passed to the underlying policy with the expression {{ inputs.bannedComponents }} 
        - ref: sbom-banned-components
          with:
            components: {{ inputs.bannedComponents }}

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Using placeholders in material names

In the previous example, our policy group enforces a sbom material. But what if our contract requires multiple SBOMs (because we are building several images in the same pipeline, for example)? By using parameters and placeholders in material names, we can add as many instances of the same policy group as we need: 
apiVersion: workflowcontract.chainloop.dev/v1
kind: PolicyGroup
metadata:
  name: sbom-quality
spec:
  inputs:
    - name: container_name
      description: name of the enforced material
      required: true
  policies:
    materials:
      - name: "{{ inputs.container_name }}" # This will materialize when doing an `attestation init`
        type: SBOM_CYCLONEDX_JSON
In our contract: 
schemaVersion: v1
materials: []
policyGroups:
  - ref: file://groups/sbom-quality-group.yaml
    with:
      container_name: "sbom-from-image-1"
  - ref: file://groups/sbom-quality-group.yaml
    with:
      container_name: "sbom-from-image-2"
And finally, in our attestation, we can see the new configuration applied: 
$ chainloop att init --workflow mywf --project myproject
INF Attestation initialized! now you can check its status or add materials to it
┌────────────────┬──────────────────────────────────────┐
│ Initialized At │ 30 Dec 24 13:21 UTC                  │
├────────────────┼──────────────────────────────────────┤
│ Attestation ID │ 0837859e-0abf-414e-b205-d455da6dfe7e │
│ Organization   │ my-org                               │
│ Name           │ mywf                                 │
│ Project        │ myproject                            │
│ Version        │ v0.148.0 (prerelease)                │
│ Contract       │ myproject-mywf (revision 77)         │
└────────────────┴──────────────────────────────────────┘
┌────────────────────────────────┐
│ Materials                      │
├──────────┬─────────────────────┤
│ Name     │ sbom-from-image-1   │
│ Type     │ SBOM_CYCLONEDX_JSON │
│ Set      │ No                  │
│ Required │ Yes                 │
├──────────┼─────────────────────┤
│ Name     │ sbom-from-image-2   │
│ Type     │ SBOM_CYCLONEDX_JSON │
│ Set      │ No                  │
│ Required │ Yes                 │
└──────────┴─────────────────────┘