ODRL-PAP

The ODRL-PAP allows to configure policies written in ODRL to be consumed by the Open Policy Agent(OPA). Therefor it translates the ODRL in to rego equivalents and offers them via the bundles-endpoint. It uses the following architecture:

API

The ODRL-PAP offers two APIS

• the Policy-API to manage policies in ODRL: OpenAPI
• the Bundle-API to offers bundles for OPA: OpenAPI
  • the methods-bundle: It contains the rego-equivalent to certain odrl-classes. The rego.methods-folder contains the initial set of methods. It can be overwritten by providing methods in a folder at paths.rego
  • the policies-bundle: It contains the actual policies and the main-policy, combining all configured policies. All request have to be evaluated against the main policy.
  • the data-bundle: Contains additional data to be taken into account for the evaluation.

Enforcement

To actually enforce policies, a Policy-Enforcment-Point is required. This role can in principle be taken by any OPA-compatible component. We recommend (and test) the usage of Apisix for that. Apisix is an OpenSource API-Gateway, that has a built-in plugin to connect OPA. See the it-test Apisix-Chart for an example configuration.

Alternative options are:

• Kong: provides an OPA-Plugin for payed-usage, format is supported by the ODRL-PAP
• Envoy: Just a proxy, no API-Gateway functionality, supports OPA integration

Translation

The translation between ODRL and Rego is based on the mapping-file. It contains the mapping between evaluatable ODRL-classes(see OdrlAttribute.java for all options) and a matching rego-method. Classes are mapped depending on their namespace and method. It allows to create domain-specific instances of odrl-classes(see dome rego-methods as example) and map them to a method.

The ODRL-PAP loads an initial set of methods on startup, that can be used to create policies. Its seperated in 3 main packages:

• utils: Contains methods to access the request and its parts. Currently it supports the inport format of apisix and kong
• odrl: Contains standard methods to work with odrl. It supports the classes action, assignee, leftOperand, operand, rightOperand, and target. Check the individual files for the concrete methods.
• dome: In order to support the DOME use-case, a number of DOME-specific methods is provided. Check the individual method files for details.

See the method-documentation for all available methods.

The set of methods can be extended by providing packages at the path configured at paths.rego in the application.properties. ODRL-PAP will scan the given folder for files with the .rego extension and offer them as part of the policies-bundle. In case of providing packages that are already included in the defaults, it will overwrite them with the newly provided one.

The mapping.json

The mapping.json provides a mapping between ODRL Classes and the corresponding rego-methods. Its keyed by the ODRL-Attribute and contains its ( namespaced) implementations. The mapping needs to contain the regoPackage(to be used for the import statement) containing the actual method and the method-invocation. To create an invocation, the input-parameters need to be taken into account. As of now, the class:

• operator requires two parameters
• operand requires one parameter
• assignee requires one parameter
• target requires one parameter
• all other require none

The parameters need to be defined with the %s placeholder. The methods can use other methods as input(f.e. from the helper) but no additional parameter replacement.

The mapping.json can be extended via a mapping file, configured at paths.mapping. If provided, all contents will be added to the default mapping. Existing keys will be overwritten, e.g. the provided one superseeds the defaults.

Running the application

Locally

To run the application together with OPA, start an instance of OPA via:

docker run -p 8181:8181 --network host -v $(pwd)/src/test/resources/opa.yaml:/opa.yaml  openpolicyagent/opa:0.63.0 run --server -c /opa.yaml

and the application via:

./mvn compile quarkus:dev

Getting familiar with policies

The project aims to take ODRL Policies and execute them using the Open Policy Agent.

In order to get familiar with the languages and tools, see test/examples.

Running the application

To test the application together with OPA, run the following:

docker run -p 8181:8181 --network host -v $(pwd)/src/test/resources/opa.yaml:/opa.yaml  openpolicyagent/opa:0.62.1 run --server -c /opa.yaml

It will mount the OPA config-file under src/test/resources/opa.yaml and start OPA at port 8181. This config tries to connect to the ODRL-PAP at localhost:8080, thus the container needs to be in the host-network. It will start to poll bundles at http://localhost:8080/bundles/service/v1/<policies.tar.gz|bundles.tar.gz>

The database:

docker run -p 5432:5432 --network host -e POSTGRES_USER=postgres -e POSTGRES_PASSWORD=postgres -e POSTGRES_DB=pap postgres

and the application:

./mvnw compile quarkus:dev -Dquarkus.http.port=8081

To try it out, create a policy:

curl -X PUT http://localhost:8081/policy/test  -H 'Content-Type: application/json' -d '{
    "@context": {
        "odrl": "http://www.w3.org/ns/odrl/2/",
        "dc": "http://purl.org/dc/elements/1.1/",
        "dct": "http://purl.org/dc/terms/",
        "owl": "http://www.w3.org/2002/07/owl#",
        "rdfs": "http://www.w3.org/2000/01/rdf-schema#",
        "skos": "http://www.w3.org/2004/02/skos/core#",
        "dome": "https://www.dome-marketplace.org/",
        "dome-op": "https://github.com/DOME-Marketplace/dome-odrl-profile#"
    },
    "@id": "https://dome-marketplace.org/policy/common/_1000",
    "@type": "odrl:Policy",
    "odrl:profile": "https://github.com/DOME-Marketplace/dome-odrl-profile/blob/main/dome-op.ttl",
    "odrl:permission": {
        "odrl:assigner": {
            "@id": "https://www.dome-marketplace.org/"
        },
        "odrl:target": "urn:ngsi-ld:product-offering:62d4f929-d29d-4070-ae1f-9fe7dd1de5f6",
        "odrl:assignee": "did:web:test.org",
        "odrl:action": {
            "@id": "odrl:read"
        }
    },
    "rdfs:isDefinedBy": {
        "@id": "dome:"
    }
}' 

The policy allows a the organization "did:web:test.org" to "read"(e.g. GET) the entity "urn:ngsi-ld:product-offering: 62d4f929-d29d-4070-ae1f-9fe7dd1de5f6".

After the polling period, the policy can be tested as following:

curl -X POST http://localhost:8181/ -H 'Content-Type: application/json' -d '{
"request": {
    "method": "GET",
    "path": "urn:ngsi-ld:product-offering:62d4f929-d29d-4070-ae1f-9fe7dd1de5f6",
    "headers": {
        "authorization" : "Bearer eyJhbGciOiJSUzI1NiIsInR5cCIgOiAiSldUIiwia2lkIiA6ICJqLUVQbXUwdUdUTmZxMDZSTGtYVllQbHpoaXI5T25MeE1sZ214RmplZjk0In0.eyJqdGkiOiJteVRlc3RUb2tlbiIsImlzcyI6ImRpZDp3ZWI6dGVzdC5vcmciLCJ2ZXJpZmlhYmxlQ3JlZGVudGlhbCI6eyJ0eXBlIjpbXSwiaXNzdWVyIjoiZGlkOndlYjp0ZXN0Lm9yZyIsImlkIjoidXJuOm15LWlkIiwiY3JlZGVudGlhbFN1YmplY3QiOnsicm9sZXNBbmREdXRpZXMiOlt7InRhcmdldCI6ImRpZDp3ZWI6dGVzdC5vcmciLCJyb2xlTmFtZXMiOlsiT3duZXIiXX1dfX19.GOesKINcyTwtkzvF9ZnZKnrNaBbzsTezrraRv6ou_Tboy9IzVmtU59o7dFxx8vHm9teuALeziqtXv4ViMTv_vnC2QcLCL9rSTfshMVeothH3SzGJ2Jb3-JUZ6Bmkpv_L5YkQCnxVBzCOnBH7Kfe3JpGwtwbI5bV0udmvyc_bXMz2SxUW9e5bYPV2WZIH06LZAk5yDPyZ4gwVKZGV1bGW-qVeI2DaQupGdeLW8ZzF4o7DGU0hhyLfuwXE6nVQUac6h8Remry1NTa99UCmSMkpICW3l8Z5kBKieek2C2mKeWu4KC5SzdTdkiG7n9_vOR7zjcfCtCuwvKdRFIcaVXN8oQ"
    }
  }
}'

The rule would evaluate to true, thus the request is accepted. If f.e. the method is changed to PUT:

curl -X POST http://localhost:8181/ -H 'Content-Type: application/json' -d '{
"request": {
    "method": "PUT",
    "path": "urn:ngsi-ld:product-offering:62d4f929-d29d-4070-ae1f-9fe7dd1de5f6",
    "headers": {
        "authorization" : "Bearer eyJhbGciOiJSUzI1NiIsInR5cCIgOiAiSldUIiwia2lkIiA6ICJqLUVQbXUwdUdUTmZxMDZSTGtYVllQbHpoaXI5T25MeE1sZ214RmplZjk0In0.eyJqdGkiOiJteVRlc3RUb2tlbiIsImlzcyI6ImRpZDp3ZWI6dGVzdC5vcmciLCJ2ZXJpZmlhYmxlQ3JlZGVudGlhbCI6eyJ0eXBlIjpbXSwiaXNzdWVyIjoiZGlkOndlYjp0ZXN0Lm9yZyIsImlkIjoidXJuOm15LWlkIiwiY3JlZGVudGlhbFN1YmplY3QiOnsicm9sZXNBbmREdXRpZXMiOlt7InRhcmdldCI6ImRpZDp3ZWI6dGVzdC5vcmciLCJyb2xlTmFtZXMiOlsiT3duZXIiXX1dfX19.GOesKINcyTwtkzvF9ZnZKnrNaBbzsTezrraRv6ou_Tboy9IzVmtU59o7dFxx8vHm9teuALeziqtXv4ViMTv_vnC2QcLCL9rSTfshMVeothH3SzGJ2Jb3-JUZ6Bmkpv_L5YkQCnxVBzCOnBH7Kfe3JpGwtwbI5bV0udmvyc_bXMz2SxUW9e5bYPV2WZIH06LZAk5yDPyZ4gwVKZGV1bGW-qVeI2DaQupGdeLW8ZzF4o7DGU0hhyLfuwXE6nVQUac6h8Remry1NTa99UCmSMkpICW3l8Z5kBKieek2C2mKeWu4KC5SzdTdkiG7n9_vOR7zjcfCtCuwvKdRFIcaVXN8oQ"        }
  }
}

It evaluates to false and is denied.

Configuration

Since the Quarkus Framework is used, its standard configuration methods can be used. See https://quarkus.io/guides/config for a detailed documentation.

The most important parameters are listed in the table below:

Property	Env-Var	Description	Default
general.organization-did	GENERAL_ORGANIZATION_DID	Did of the organization running the pap. Is used for evaluating roles in the DOME use-case(see dome-op:role)
general.pep	GENERAL_PEP	The PEP to be supported. Will decide about the input format used for the policies. Currently apisix and kong are supported.	apisix
quarkus.datasource.username	QUARKUS_DATASOURCE_USERNAME	Username to be used for connecting the database.	postgres
quarkus.datasource.password	QUARKUS_DATASOURCE_PASSWORD	Password to be used for connecting the database.	postgres
quarkus.datasource.jdbc.url	QUARKUS_DATASOURCE_JDBC_URL	Connection string to the DB, only postgres is supported at the moment.	jdbc:postgresql://localhost:5432/pap
paths.mapping	PATHS_MAPPING	Path to an additional mapping.json	null
paths.rego	PATHS_REGO	Path to additional rego packages.	null

Test

API Tests can be executed via:

  mvn clean test

It will spin-up OPA and MockServer to test policy creation through the ODRL-PAP.

The IT-Tests are intended to be as close to a production environment as possible. Therefor, create the (native) image first:

  mvn clean package -Dnative -Dquarkus.container-image.build=true

The image will automatically be copied to the k3s-cluster, running the tests. Start the tests via:

  mvn clean install -Pk8s-it

The test will spin up a k3s-cluster, with the ODRL-PAP, an instance of OPA, a MockServer to provide the request target and Apisix as the Policy-Enforcement-Point. If you want to use such environment for development, use:

  mvn clean install -Pdev

Creating a native executable

⚠️ If you add any rego-resource, execute ./scripts/create-rego-resource-list.sh first. It updates the list of rego-resource, so that the native application can access them properly.

You can create a native executable using:

./mvnw package -Dnative

Or, if you don't have GraalVM installed, you can run the native executable build in a container using:

./mvnw package -Dnative -Dquarkus.container-image.build=true

You can then execute your native executable with: ./target/odrl-poc-1.0.0-SNAPSHOT-runner

If you want to learn more about building native executables, please consult https://quarkus.io/guides/maven-tooling.

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