docs/policy-agent-api.rst

.. This work is licensed under a Creative Commons Attribution 4.0 International License.
.. http://creativecommons.org/licenses/by/4.0
.. Copyright (C) 2020 Nordix

.. |nbsp| unicode:: 0xA0
   :trim:

.. |nbh| unicode:: 0x2011
   :trim:

.. _policy-agent-api:

############################
A1 Policy Management Service
############################


*******************************************
A1 Policy Management Service - Introduction
*******************************************

The A1 Policy Management Service ("Policy Agent") is an SMO/NONRTRIC service above the NONRTRIC A1 Adaptor/Controller
that provides:

* Unified REST & DMAAP APIs for managing A1 Policies in all Near |nbh| RT |nbsp| RICs
* Synchronized view of registered "services" (e.g. R-APP, GUI, etc)
* Synchronized view of policy instances for each "service"
* Synchronized view of policy instances in all Near |nbh| RT |nbsp| RICs
* Synchronized view of policy types in all Near |nbh| RT |nbsp| RICs
* Policy Query API (e.g. per Near |nbh| RT |nbsp| RIC, per "service", per policy type)
* An initial interface for unified Near |nbh| RT |nbsp| RIC ID to Near |nbh| RT |nbsp| RIC address mapping.
  (Note:  may also later act as adaptor to A&AI, CMDBs etc. to "find" Near |nbh| RT |nbsp| RICs - TBC)
* An Initial "O1 ManagedElement" mapping database & interface to find appropriate Near |nbh| RT |nbsp| RIC for RAN elements.
  (Note: may also later act as adaptor to A&AI, RuntimeDB, other CMDBs etc. - TBC)
* Monitors all Near |nbh| RT |nbsp| RICs and recovers from inconsistencies (Note: e.g. Near |nbh| RT |nbsp| RIC restarts)
* Support for different Southbound connectors on a per Near |nbh| RT |nbsp| RIC basis. (Note: e.g. different A1
  versions, different Near |nbh| RT |nbsp| RIC versions, different A1 adapters, different or proprietary A1
  controllers/EMSs)

***************************************
A1 Policy Management Service - REST NBI
***************************************

This is the north bound API of the A1 Policy Management Service ("Policy Agent"). This API allows *services* to interact
with the Policy Agent using REST.

By registering with the Policy Agent, the Policy Agent takes responsibility for synchronizing the policies created by
the service in the Near |nbh| RT |nbsp| RICs. This means that if a Near |nbh| RT |nbsp| RIC restarts, the Policy Agent
will try to recreate all the policies residing in the Near |nbh| RT |nbsp| RIC once it is started again. If this is not
possible, it will remove all policies belonging to the Near |nbh| RT |nbsp| RIC.

The Policy Agent also keeps an updated view of the policy types available, and which Near |nbh| RT |nbsp| RICs that
support which types. Also, the Policy Agent can tell if a Managed Element is managed by a certain
Near |nbh| RT |nbsp| RIC.

The Policy Agent NBI has four distinct parts, described in the sections below:

* Service Management
* Policy Management
* Near-RT RIC Repository
* Health Check

.. contents:: Operations
   :depth: 4
   :local:


Service Management
==================

A service can register itself in the Policy Agent.

By providing a callback URL the service can get notifications from the Policy Agent.

A service can also register a "*Keep Alive Interval*", in seconds. By doing this the service promises to call the
Policy Agent's "*Keep Alive*" method, or else create or delete policies, more often than the "*Keep Alive Interval*"
measured in seconds. If the service, for some reason, is not able to do this, the Policy Agent will consider that the
service has died or vanished and will then delete all its policies, both in the internal repository and in the
Near |nbh| RT |nbsp| RICs where they were earlier created. **Note!** |nbsp| If the service does not provide a value for
"*Keep Alive Interval*", then the service maintains full responsibility to delete all of its policies when they are no
longer needed.

Service Management Operations
-----------------------------

/service
~~~~~~~~

PUT
+++

  Register a service.

  **URL path:**
    /service

  **Parameters:**

    None.

  **Body:**  (*Required*)
      A JSON object (ServiceRegistrationInfo): ::

        {
          "callbackUrl": "string",         (An empty string means the service will never get any callbacks.)
          "keepAliveIntervalSeconds": 0,   (0 means the service will always be considered alive.)
          "serviceName": "string"          (Required, must be unique.)
        }

  **Responses:**

    200:
          Service updated.

    201:
          Service created.

    400:
          The ServiceRegistrationInfo is not accepted.

  **Examples:**

    Call: ::

      curl -X PUT "http://localhost:8081/service" -H "Content-Type: application/json" -d "{
          \"callbackUrl\": \"URL\",
          \"keepAliveIntervalSeconds\": 0,
          \"serviceName\": \"existing\"
        }"

    Result:
      201: ::

         OK

    Call: ::

       curl -X PUT "http://localhost:8081/service" -H  "Content-Type: application/json" -d "{}"

    Result:
       400: ::

         Missing mandatory parameter 'serviceName'

/services
~~~~~~~~~

GET
+++

  Query service information.

  **URL path:**
    /services?name=<service-name>

  **Parameters:**

    name: (*Optional*)
      The name of the service.

  **Responses:**

    200:
          Array of JSON objects (ServiceStatus). ::

           {
               "callbackUrl": "string",             (Callback URL)
               "keepAliveIntervalSeconds": 0,       (Policy keep alive interval)
               "serviceName": "string",             (Identity of the service)
               "timeSinceLastActivitySeconds": 0    (Time since last invocation by the service)
           }

    404:
          Service is not found.

  **Examples:**

    Call: ::

      curl -X GET "http://localhost:8081/services?name=existing"

    Result:
      200: ::

         [
           {
             "serviceName":"existing",
             "keepAliveIntervalSeconds":0,
             "timeSinceLastActivitySeconds":7224,
             "callbackUrl":"URL"
           }
        ]

    Call: ::

      curl -X GET "http://localhost:8081/services?name=nonexistent"

    Result:
       404: ::

         Service not found

DELETE
++++++

  Delete a service.

  **URL path:**
    /services?name=<service-name>

  **Parameters:**

    name: (*Required*)
      The name of the service.

  **Responses:**

    204:
          OK

    404:
          Service not found.

  **Examples:**

    Call: ::

      curl -X DELETE "http://localhost:8081/services?name=existing"

    Result:
      204: ::

         OK

    Call: ::

      curl -X DELETE "http://localhost:8081/services?name=nonexistent"

    Result:
       404: ::

         Could not find service: nonexistent

/services/keepalive
~~~~~~~~~~~~~~~~~~~

PUT
+++

  Heart beat from a service.

  **URL path:**
    /services/keepalive?name=<service-name>

  **Parameters:**

    name: (*Required*)
      The name of the service.

  **Responses:**

    200:
          OK

    404:
          Service is not found.

  **Examples:**

    Call: ::

      curl -X PUT "http://localhost:8081/services/keepalive?name=existing"

    Result:
      200: ::

         OK

    Call: ::

      curl -X PUT "http://localhost:8081/services/keepalive?name=nonexistent"

    Result:
       404: ::

         Could not find service: nonexistent

.. _policy-management:

Policy Management
=================

Policies are based on types. The set of available policy types is determined by the set of policy types supported by
Near |nbh| RT |nbsp| RICs. At startup, the Policy Agent queries all Near |nbh| RT |nbsp| RICs for their supported types
and stores them in its internal repository. It then checks this at regular intervals to keep the repository of types up
to date. Policy types cannot be created, updated or deleted using this interface since this must be done via the
Near |nbh| RT |nbsp| RICs.

Policies can be queried, created, updated, and deleted. A policy is always created in a specific
Near |nbh| RT |nbsp| RIC.

When a policy is created, the Policy Agent stores information about it in its internal repository. At regular intervals,
it then checks with all Near |nbh| RT |nbsp| RICs that this repository is synchronized. If, for some reason, there is an
inconsistency, the Policy Agent will start a synchronization job and try to reflect the status of the
Near |nbh| RT |nbsp| RIC. If this fails, the Policy Agent will delete all policies for the specific
Near |nbh| RT |nbsp| RIC in the internal repository and set its state to *UNKNOWN*. This means that no interaction with
the Near |nbh| RT |nbsp| RIC is possible until the Policy Agent has been able to contact it again and re-synchronize its
state in the repository.

Policy Types
------------

A policy type defines a name and a JSON schema that constrains the content of a policy of that type.

/policy_types
~~~~~~~~~~~~~

GET
+++

  Query policy type names.

  **URL path:**
    /policy_types?ric=<name-of-ric>

  **Parameters:**

    ric: (*Optional*)
      The name of the Near |nbh| RT |nbsp| RIC to get types for.

  **Responses:**

    200:
          Array of policy type names.

    404:
          Near |nbh| RT |nbsp| RIC is not found.

  **Examples:**

    Call: ::

      curl -X GET "http://localhost:8081/policy_types"

    Result:
      200: ::

         [
           "STD_PolicyModelUnconstrained_0.2.0",
           "Example_QoETarget_1.0.0",
           "ERIC_QoSNudging_0.2.0"
        ]

    Call: ::

      curl -X GET "http://localhost:8081/policy_types?ric=nonexistent"

    Result:
       404: ::

         org.oransc.policyagent.exceptions.ServiceException: Could not find ric: nonexistent

/policy_schema
~~~~~~~~~~~~~~

GET
+++

  Returns one policy type schema definition.

  **URL path:**
    /policy_schema?id=<name-of-type>

   **Parameters:**

    id: (*Required*)
      The ID of the policy type to get the definition for.

  **Responses:**

    200:
          Policy schema as JSON schema.

    404:
          Policy type is not found.

  **Examples:**

    Call: ::

      curl -X GET "http://localhost:8081/policy_schema?id=STD_PolicyModelUnconstrained_0.2.0"

    Result:
      200: ::

        {
          "$schema": "http://json-schema.org/draft-07/schema#",
          "title": "STD_PolicyModelUnconstrained_0.2.0",
          "description": "Standard model of a policy with unconstrained scope id combinations",
          "type": "object",
          "properties": {
           "scope": {
              "type": "object",
              "properties": {
                "ueId": {"type": "string"},
                "groupId": {"type": "string"}
              },
              "minProperties": 1,
              "additionalProperties": false
            },
            "qosObjectives": {
              "type": "object",
              "properties": {
                "gfbr": {"type": "number"},
                "mfbr": {"type": "number"}
              },
              "additionalProperties": false
            },
            "resources": {
              "type": "array",
              "items": {
                "type": "object",
                "properties": {
                  "cellIdList": {
                    "type": "array",
                    "minItems": 1,
                    "uniqueItems": true,
                    "items": {
                      "type": "string"
                    }
                  },
                "additionalProperties": false,
                "required": ["cellIdList"]
              }
            }
          },
          "minProperties": 1,
          "additionalProperties": false,
          "required": ["scope"]
        }

    Call: ::

      curl -X GET "http://localhost:8081/policy_schema?id=nonexistent"

    Result:
       404: ::

         org.oransc.policyagent.exceptions.ServiceException: Could not find type: nonexistent

/policy_schemas
~~~~~~~~~~~~~~~

GET
+++

  Returns policy type schema definitions.

  **URL path:**
    /policy_schemas?ric=<name-of-ric>

   **Parameters:**

    ric: (*Optional*)
      The name of the Near |nbh| RT |nbsp| RIC to get the definitions for.

  **Responses:**

    200:
          An array of policy schemas as JSON schemas.

    404:
          Near |nbh| RT |nbsp| RIC is not found.

  **Examples:**

    Call: ::

      curl -X GET "http://localhost:8081/policy_schemas"

    Result:
      200: ::

        [{
          "$schema": "http://json-schema.org/draft-07/schema#",
          "title": "STD_PolicyModelUnconstrained_0.2.0",
          "description": "Standard model of a policy with unconstrained scope id combinations",
          "type": "object",
          "properties": {
           "scope": {
              "type": "object",
              .
              .
              .
          "additionalProperties": false,
          "required": ["scope"]
        },
         .
         .
         .
        {
          "$schema": "http://json-schema.org/draft-07/schema#",
          "title": "Example_QoETarget_1.0.0",
          "description": "Example QoE Target policy type",
          "type": "object",
          "properties": {
           "scope": {
              "type": "object",
              .
              .
              .
          "additionalProperties": false,
          "required": ["scope"]
        }]

    Call:
      curl -X GET "http://localhost:8081/policy_schemas?ric=nonexistent"

    Result:
       404: ::

         org.oransc.policyagent.exceptions.ServiceException: Could not find ric: nonexistent

Policy
------

A policy is defined by its type schema.

Once a service has created a policy, it is the service's responsibility to maintain its life cycle. Since policies are
transient, they will not survive a restart of a Near |nbh| RT |nbsp| RIC. But this is handled by the Policy Agent. When
a Near |nbh| RT |nbsp| RIC has been restarted, the Policy Agent will try to recreate the policies in the
Near |nbh| RT |nbsp| RIC that are stored in its local repository. This means that the service always must delete any
policy it has created. There are only two exceptions, see below:

- The service has registered a "*Keep Alive Interval*", then its policies will be deleted if it fails to notify the
  Policy Agent in due time.
- The Policy Agent completely fails to synchronize with a Near |nbh| RT |nbsp| RIC.

/policies
~~~~~~~~~

GET
+++

  Query policies.

  **URL path:**
    /policies?ric=<name-of-ric>&service=<name-of-service>&type=<name-of-type>

  **Parameters:**

    ric: (*Optional*)
      The name of the Near |nbh| RT |nbsp| RIC to get policies for.

    service: (*Optional*)
      The name of the service to get policies for.

    type: (*Optional*)
      The name of the policy type to get policies for.

  **Responses:**

    200:
          Array of JSON objects (PolicyInfo). ::

            {
              "id": "string",              (Identity of the policy)
              "json": "object",            (The configuration of the policy)
              "lastModified": "string",    (Timestamp, last modification time)
              "ric": "string",             (Identity of the target Near |nbh| RT |nbsp| RIC)
              "service": "string",         (The name of the service owning the policy)
              "type": "string"             (Name of the policy type)
            }

    404:
          Near |nbh| RT |nbsp| RIC or policy type not found.

  **Examples:**

    Call: ::

      curl -X GET "http://localhost:8081/policies?ric=existing"

    Result:
      200: ::

         [
           {
             "id": "Policy 1",
             "json": {
               "scope": {
                 "ueId": "UE 1",
                 "groupId": "Group 1"
               },
               "qosObjectives": {
                 "gfbr": 1,
                 "mfbr": 2
               },
               "cellId": "Cell 1"
             },
             "lastModified": "Wed, 01 Apr 2020 07:45:45 GMT",
             "ric": "existing",
             "service": "Service 1",
             "type": "STD_PolicyModelUnconstrained_0.2.0"
           },
           {
             "id": "Policy 2",
             "json": {
                 .
                 .
                 .
             },
             "lastModified": "Wed, 01 Apr 2020 07:45:45 GMT",
             "ric": "existing",
             "service": "Service 2",
             "type": "Example_QoETarget_1.0.0"
           }
        ]

    Call: ::

      curl -X GET "http://localhost:8081/policies?type=nonexistent"

    Result:
       404: ::

         Policy type not found

/policy
~~~~~~~

GET
+++

  Returns a policy configuration.

  **URL path:**
    /policy?id=<policy-id>

  **Parameters:**

    id: (*Required*)
      The ID of the policy instance.

  **Responses:**

    200:
          JSON object containing policy information. ::

            {
              "id": "string",                  (ID of policy)
              "json": "object",                (JSON with policy data speified by the type)
              "ownerServiceName": "string",    (Name of the service that created the policy)
              "ric": "string",                 (Name of the Near |nbh| RT |nbsp| RIC where the policy resides)
              "type": "string",                (Name of the policy type of the policy)
              "lastModified"                   (Timestamp, last modification time)
            }

    404:
          Policy is not found.

  **Examples:**

    Call: ::

      curl -X GET "http://localhost:8081/policy?id=Policy 1"

    Result:
      200: ::

         {
           "id": "Policy 1",
           "json", {
             "scope": {
               "ueId": "UE1 ",
               "cellId": "Cell 1"
             },
             "qosObjectives": {
               "gfbr": 319.5,
               "mfbr": 782.75,
               "priorityLevel": 268.5,
               "pdb": 44.0
             },
             "qoeObjectives": {
               "qoeScore": 329.0,
               "initialBuffering": 27.75,
               "reBuffFreq": 539.0,
               "stallRatio": 343.0
             },
             "resources": []
           },
           "ownerServiceName": "Service 1",
           "ric": "ric1",
           "type": "STD_PolicyModelUnconstrained_0.2.0",
           "lastModified": "Wed, 01 Apr 2020 07:45:45 GMT"
         }

    Call: ::

      curl -X GET "http://localhost:8081/policy?id=nonexistent"

    Result:
       404: ::

         Policy is not found

PUT
+++

  Create/Update a policy. **Note!** Calls to this method will also trigger "*Keep Alive*" for a service which has a
  "*Keep Alive Interval*" registered.

  **URL path:**
    /policy?id=<policy-id>&ric=<name-of-ric>&service=<name-of-service>&type=<name-of-policy-type>

  **Parameters:**

    id: (*Required*)
      The ID of the policy instance.

    ric: (*Required*)
      The name of the Near |nbh| RT |nbsp| RIC where the policy will be created.

    service: (*Required*)
      The name of the service creating the policy.

    type: (*Optional*)
      The name of the policy type.

  **Body:** (*Required*)
      A JSON object containing the data specified by the type.

  **Responses:**

    200:
          Policy updated.

    201:
          Policy created.

    404:
          Near |nbh| RT |nbsp| RIC or policy type is not found.

    423:
          Near |nbh| RT |nbsp| RIC is not operational.

  **Examples:**

    Call: ::

      curl -X PUT "http://localhost:8081/policy?id=Policy%201&ric=ric1&service=Service%201&type=STD_PolicyModelUnconstrained_0.2.0"
        -H  "Content-Type: application/json"
        -d "{
              \"scope\": {
                \"ueId\": \"UE 1\",
                \"cellId\": \"Cell 1\"
              },
              \"qosObjectives\": {
                \"gfbr\": 319.5,
                \"mfbr\": 782.75,
                \"priorityLevel\": 268.5,
                \"pdb\": 44.0
              },
              \"qoeObjectives\": {
                \"qoeScore\": 329.0,
                \"initialBuffering\": 27.75,
                \"reBuffFreq\": 539.0,
                \"stallRatio\": 343.0
              },
              \"resources\": []
            }"

    Result:
      200

DELETE
++++++

  Deletes a policy. **Note!** Calls to this method will also trigger "*Keep Alive*" for a service which has a
  "*Keep Alive Interval*" registered.

  **URL path:**
    /policy?id=<policy-id>

  **Parameters:**

    id: (*Required*)
      The ID of the policy instance.

  **Responses:**

    204:
          Policy deleted.

    404:
          Policy is not found.

    423:
          Near |nbh| RT |nbsp| RIC is not operational.

  **Examples:**

    Call: ::

      curl -X DELETE "http://localhost:8081/policy?id=Policy 1"

    Result:
      204

/policy_ids
~~~~~~~~~~~

GET
+++

  Query policy type IDs.

  **URL path:**
    /policy_ids?ric=<name-of-ric>&service=<name-of-service>&type=<name-of-policy-type>

  **Parameters:**

    ric: (*Optional*)
      The name of the Near |nbh| RT |nbsp| RIC to get policies for.

    service: (*Optional*)
      The name of the service to get policies for.

    type: (*Optional*)
      The name of the policy type to get policies for.

  **Responses:**

    200:
          Array of policy type names.

    404:
          RIC or policy type not found.

  **Examples:**

    Call: ::

      curl -X GET "http://localhost:8081/policy_ids"

    Result:
      200: ::

         [
           "Policy 1",
           "Policy 2",
           "Policy 3"
        ]

    Call: ::

      curl -X GET "http://localhost:8081/policy_ids?ric=nonexistent"

    Result:
       404: ::

         Ric not found

/policy_status
~~~~~~~~~~~~~~

GET
+++

  Returns the status of a policy.

  **URL path:**
    /policy_status?id=<policy-id>

  **Parameters:**

    id: (*Required*)
      The ID of the policy.

  **Responses:**

    200:
          JSON object with policy status.

    404:
          Policy not found.

Near-RT RIC Repository
======================

The Policy Agent keeps an updated view of the Near |nbh| RT |nbsp| RICs that are available in the system. A service can
find out which Near |nbh| RT |nbsp| RIC that manages a specific element in the network or which
Near |nbh| RT |nbsp| RICs that support a specific policy type.

Near-RT RIC
-----------

/ric
~~~~

GET
+++

  Returns the name of a Near |nbh| RT |nbsp| RIC managing a specific Mananged Element.

   **URL path:**
    /ric?managedElementId=<id-of-managed-element>

  **Parameters:**

    managedElementId: (*Required*)
      The ID of the Managed Element.

  **Responses:**

    200:
          Name of the Near |nbh| RT |nbsp| RIC managing the Managed Element.

    404:
          No Near |nbh| RT |nbsp| RIC manages the given Managed Element.

  **Examples:**

    Call: ::

      curl -X GET "http://localhost:8081/ric?managedElementId=Node 1"

    Result:
      200: ::

        Ric 1

    Call: ::

      curl -X GET "http://localhost:8081/ric?managedElementId=notmanaged"

    Result:
       404

/rics
~~~~~

GET
+++

  Query Near |nbh| RT |nbsp| RIC information.

   **URL path:**
    /rics?policyType=<name-of-policy-type>

  **Parameters:**

    policyType: (*Optional*)
      The name of the policy type.

  **Responses:**

    200:
          Array of JSON objects containing Near |nbh| RT |nbsp| RIC information. ::

            [
              {
                "managedElementIds": [
                  "string"
                ],
                "policyTypes": [
                  "string"
                ],
                "ricName": "string",
                "state": "string"
              }
            ]

    404:
          Policy type is not found.

  **Examples:**

    Call: ::

      curl -X GET "http://localhost:8081/rics?policyType=STD_PolicyModelUnconstrained_0.2.0"

    Result:
      200: ::

        [
          {
            "managedElementIds": [
              "ME 1",
              "ME 2"
            ],
            "policyTypes": [
              "STD_PolicyModelUnconstrained_0.2.0",
              "Example_QoETarget_1.0.0",
              "ERIC_QoSNudging_0.2.0"
            ],
            "ricName": "Ric 1",
            "state": "AVAILABLE"
          },
            .
            .
            .
          {
            "managedElementIds": [
              "ME 3"
            ],
            "policyTypes": [
              "STD_PolicyModelUnconstrained_0.2.0"
            ],
            "ricName": "Ric X",
            "state": "UNAVAILABLE"
          }
        ]

    Call: ::

      curl -X GET "http://localhost:8081/rics?policyType=nonexistent"

    Result:
       404: ::

        Policy type not found

Health Check
============

The status of the Policy Agent.

Health Check
------------

/status
~~~~~~~

GET
+++

  Returns the status of the Policy Agent.

   **URL path:**
    /status

  **Parameters:**

    None.

  **Responses:**

    200:
          Service is living.

  **Examples:**

    Call: ::

      curl -X GET "http://localhost:8081/status"

    Result:
      200

****************
A1 through DMaaP
****************

The Policy Agent also provides the possibility to use DMaap to handle policies according to the A1 specification. The
Policy Agent polls the DMaaP Message Router regularly and processes any messages targeted to it. The response is then
published back to the DMaaP Message Router with the result of the call.

Send Message
============

The message to send is a JSON like the one below. The "*url*" is one of the URLs described under
:ref:`policy-management`. The "*target*" must always be "*policy-agent*" for the message to be processed by the Policy
Agent. The "*operation*" can be one of the following: "*GET | PUT | POST | DELETE*". ::

  {
    "type": "string",
    "correlationId": "string",
    "target": "string",
    "timestamp": "timestamp",
    "apiVersion": "string",
    "originatorId": "string",
    "requestId": "string",
    "operation": "string",
    "url": "string"
  }

Example
-------

To get all policy types for a specific Near |nbh| RT |nbsp| RIC the following message should be sent to DMaaP Message
Router: ::

  {
    "type":"request",
    "correlationId":"c09ac7d1-de62-0016-2000-e63701125557-201",
    "target":"policy-agent",
    "timestamp":"2019-05-14T11:44:51.36Z",
    "apiVersion":"1.0",
    "originatorId":"849e6c6b420",
    "requestId":"23343221",
    "operation":"GET",
    "url":"/policy_schemas?ric=ric_ric-simulator_1"
  }

Receive Message
===============

The message the Policy Agent sends back to the DMaaP Message Router is a JSON like the one below. The "*requestId*"
"*correlationId*", and "*originatorId*" are the same as in the message sent to DMaaP MR. ::

  {
    "requestId": "string",
    "correlationId": "string",
    "originatorId": "string",
    "type": "string",
    "message": "string",
    "type":  string",
    "timestamp": "string",
    "status": "string"
  }

Example
-------

The response containing all policy types for a specific Near |nbh| RT |nbsp| RIC sent to the DMaaP Message Router from
the Policy Agent: ::

  {
    \"requestId\":\"23343221\",
    \"correlationId\":\"c09ac7d1-de62-0016-2000-e63701125557-201\",
    \"originatorId\":\"849e6c6b420\",
    \"type\":\"response\",
    \"message\":\"[
      {
      \\\"$schema\\\":\\\"http://json-schema.org/draft-07/schema#\\\",
      \\\"description\\\":\\\"QoS policy type\\\",
      \\\"title\\\":\\\"STD_QoSNudging_0.2.0\\\",
      \\\"type\\\":\\\"object\\\",
      \\\"properties\\\":{\\\"scope\\\":{\\\"additionalProperties\\\":true,
      \\\"type\\\":\\\"object\\\",
      \\\"properties\\\":{\\\"qosId\\\":{\\\"type\\\":\\\"string\\\"},
      \\\"ueId\\\":{\\\"type\\\":\\\"string\\\"}},
      \\\"required\\\":[\\\"ueId\\\",
      \\\"qosId\\\"]},
      \\\"statement\\\":{\\\"additionalProperties\\\":false,
      \\\"type\\\":\\\"object\\\",
      \\\"properties\\\":{\\\"priorityLevel\\\":{\\\"type\\\":\\\"number\\\"}},
      \\\"required\\\":[\\\"priorityLevel\\\"]}}
      }
    ]\",
    \"timestamp\":\"2019-05-14T11:44:51.36Z\",
    \"status\":\"200 OK\"
  }