Design and Public API documentation completed.

The draw.io diagrams are in Gerrit. If the page is ever deleted, they
will be lost. They ae now saved in XML format in gerrit.

The design documentation links to the examples in github rather than
quoting them in the document. General tidy up and cleaning of links,
rewording, and reformatting of desgin document.

Added missing diagram to the Design document.

Updated and tidied up the internal PAP/PDP document.

General improvement of documentation.

Issue-ID: POLICY-1676
Change-Id: Ie5c9f32693f047beafe14a3e412a32cdf9ed6fde
Signed-off-by: liamfallon <liam.fallon@est.tech>

1 files changed, 103 insertions, 46 deletions

diff --git a/docs/pap/pap.rst b/docs/pap/pap.rst
index a76ab807..b420279c 100644
--- a/docs/pap/pap.rst
+++ b/docs/pap/pap.rst
@@ -4,29 +4,53 @@
 .. _pap-label:
 
 Policy Administration Point (PAP) Architecture
-==============================================
-.. toctree::
+##############################################
 
-The PAP keeps track of PDPs, supporting the deployment of PDP groups and the
-deployment of a *policy set* across those PDP groups.  Policies are created
-using the Policy API, but are deployed via the PAP. 
+.. contents::
+    :depth: 3
 
-A PAP is stateless in
-a RESTful sense, using the database (persistent storage) to track PDPs and
-the deployment of policies to those PDPs. In short, policy management on PDPs
-is the responsibility of PAPs; management of policy sets or policies by any
-other manner is not permitted.
+The PAP keeps track of PDPs, supporting the deployment of PDP groups and the deployment of a *policy set* across those
+PDP groups. Policies are created using the Policy API, but are deployed via the PAP. 
 
-Because the PDP is the main unit of scalability in the Policy Framework, the
-framework is designed to allow PDPs in a PDP group to arbitrarily appear and
-disappear and for policy consistency across all PDPs in a PDP group to be
-easily maintained.  The PAP is responsible for controlling the state across
-the PDPs in a PDP group. The PAP interacts with the Policy database and
-transfers policy sets to PDPs.
+A PAP is stateless in a RESTful sense, using the database (persistent storage) to track PDPs and the deployment of
+policies to those PDPs. In short, policy management on PDPs is the responsibility of PAPs; management of policy sets or
+policies by any other manner is not permitted.
 
+Because the PDP is the main unit of scalability in the Policy Framework, the framework is designed to allow PDPs in a
+PDP group to arbitrarily appear and disappear and for policy consistency across all PDPs in a PDP group to be easily
+maintained. The PAP is responsible for controlling the state across the PDPs in a PDP group. The PAP interacts with the
+Policy database and transfers policy sets to PDPs.
 
-REST API
---------
+There are a number of rules for PDP group and PDP state management:
+
+1. Only one version of a PDP group may be ACTIVE at any time
+
+2. If a PDP group with a certain version is ACTIVE and a later version   of the same PDP group is activated, then the
+   system upgrades the PDP group
+
+3. If a PDP group with a certain version is ACTIVE and an earlier version of the same PDP group is activated, then the
+   system downgrades the PDP group
+
+4. There is no restriction on the number of PASSIVE versions of a PDP group that can exist in the system
+
+
+1 APIs
+======
+The APIs in the subchapters below are supported by the PAP.
+
+1.1 REST API
+------------
+
+The purpose of this API is to support CRUD of PDP groups and subgroups and to support the deployment and life cycles of
+policies on PDP sub groups and PDPs. This API is provided by the *PolicyAdministration* component (PAP) of the Policy
+Framework, see the :ref:`ONAP Policy Framework Architecture <architecture-label>` page.
+
+PDP groups and subgroups may be prefedined in the system. Predefined groups and subgroups may be modified or deleted
+over this API. The policies running on predefined groups or subgroups as well as the instance counts and properties may
+also be modified.
+
+A PDP may be preconfigured with its PDP group, PDP subgroup, and policies. The PDP sends this information to the PAP
+when it starts. If the PDP group, subgroup, or any policy is unknown to the PAP, the PAP locks the PDP in state PASSIVE.
 
 PAP supports the operations listed in the following table, via its REST API:
 
@@ -43,9 +67,8 @@ PAP supports the operations listed in the following table, via its REST API:
    "Deploy policy", "Deploys one or more policies to the PDPs"
    "Undeploy policy", "Undeploys a policy from the PDPs"
 
-
-DMaaP API
----------
+1.2 DMaaP API
+-------------
 
 PAP interacts with the PDPs via the DMaaP Message Router.  The messages listed
 in the following table are transmitted via DMaaP:
@@ -59,20 +82,20 @@ in the following table are transmitted via DMaaP:
    "PDP state change", "Outgoing", "Changes the state of a PDP or all PDPs within a PDP Group or Subgroup"
 
 
-PAP REST API Swagger
---------------------
+2 PAP REST API Swagger
+======================
 
-It is worth noting that we use basic authorization for access with user name
-and password set to *healthcheck* and *zb!XztG34*, respectively.
+It is worth noting that we use basic authorization for access with user name and password set to *healthcheck* and
+*zb!XztG34*, respectively.
 
-For every call, the client is encouraged to insert a uuid-type *requestID* as
-parameter. It is helpful for tracking each http transaction and facilitates
-debugging. More importantly, it complies with Logging requirements v1.2. If
-the client does not provide the requestID in a call, one will be randomly
-generated and attached to the response header, *x-onap-requestid*.
+For every call, the client is encouraged to insert a uuid-type *requestID* as parameter. It is helpful for tracking each
+http transaction and facilitates debugging. More importantly, it complies with Logging requirements v1.2. If the client
+does not provide the requestID in a call, one will be randomly generated and attached to the response header,
+*x-onap-requestid*.
 
-In accordance with `ONAP API Common Versioning Strategy Guidelines <https://wiki.onap.org/display/DW/ONAP+API+Common+Versioning+Strategy+%28CVS%29+Guidelines>`_,
-several custom headers are added in the response to each call:
+In accordance with `ONAP API Common Versioning Strategy Guidelines
+<https://wiki.onap.org/display/DW/ONAP+API+Common+Versioning+Strategy+%28CVS%29+Guidelines>`_, several custom headers
+are added in the response to each call:
 
 .. csv-table::
    :header: "Header", "Example value", "Description"
@@ -86,37 +109,71 @@ several custom headers are added in the response to each call:
 
 .. swaggerv2doc:: swagger/health-check-pap.json
 
+This operation performs a health check on the PAP.
+
 .. swaggerv2doc:: swagger/statistics-pap.json
 
-Note: while this API is supported, most of the statistics
-are not currently updated; that work has been deferred to a later release.
+This operation allows statistics for PDP groups, PDP subgroups, and individual PDPs to be retrieved.
+
+.. note::
+  While this API is supported, most of the statistics are not currently updated; that work has been deferred to a later
+  release.
 
 .. swaggerv2doc:: swagger/state-change-pap.json
 
+The state of PDP groups is managed by this operation. PDP groups can be in states PASSIVE, TEST, SAFE, or ACTIVE. For a full
+description of PDP group states, see the :ref:`ONAP Policy Framework Architecture <architecture-label>` page.
+
 .. swaggerv2doc:: swagger/group-pap.json
 
-Note: due to current limitations, if a subgroup is to be deleted from a PDP
-Group, then the policies must be removed from the subgroup in one request,
-and then the subgroup deleted in a subsequent request.
+This operation allows the PDP groups and subgroups to be created and updated. Many PDP groups can be created or updated
+in a single POST operation by specifying more than one PDP group in the POST operation body.
+
+.. note::
+  Due to current limitations, if a subgroup is to be deleted from a PDP Group, then the policies must be removed from
+  the subgroup in one request, and then the subgroup deleted in a subsequent request.
 
 .. swaggerv2doc:: swagger/group-delete-pap.json
 
+The API also allows PDP groups to be deleted. DELETE operations are only permitted on PDP groups in PASSIVE state.
+
 .. swaggerv2doc:: swagger/group-query-pap.json
 
+This operation allows the PDP groups and subgroups to be listed as well as the policies that are deployed on each PDP
+group and subgroup.
+
 .. swaggerv2doc:: swagger/policy-deploy-pap.json
 
-Note: the policy version is optional.  If left unspecified, then the latest
-version of the policy is deployed. On the other hand, if it is specified, it
-may be an integer, or it may be a fully qualified version (e.g., "3.0.2").
+This operation allows policies to be deployed on PDP groups.
+
+.. note::
+  The policy version is optional.  If left unspecified, then the latest version of the policy is deployed. On the other
+  hand, if it is specified, it may be an integer, or it may be a fully qualified version (e.g., "3.0.2").
 
 .. swaggerv2doc:: swagger/policy-undeploy-pap.json
 
-Note: if the policy version is specified, then it
-may be an integer, or it may be a fully qualified version (e.g., "3.0.2").
-On the other hand, if left unspecified, then the latest deployed version
-will be undeployed.
+This operation allows policies to be undeployed from PDP groups.
+
+.. note::
+  If the policy version is specified, then it may be an integer, or it may be a fully qualified version (e.g., "3.0.2").
+  On the other hand, if left unspecified, then the latest deployed version will be undeployed.
+
+.. note::
+  Due to current limitations, a fully qualified policy version must always be specified.
+  
+3 Future Features 
+=================
+
+3.1 Order Health Check on PDPs
+==============================
+
+This operation will allow a PDP group health check to be ordered on PDP groups and on individual PDPs. The operation
+will return a HTTP status code of *202: Accepted* if the health check request has been accepted by the PAP. The PAP will
+then order execution of the health check on the PDPs.
+
+As health checks may be long lived operations, Health checks will be scheduled for execution by this operation. Users
+will check the result of a health check test by issuing a PDP Group Query operation and checking the *healthy* field of
+PDPs.
 
-Note: due to current limitations, a fully qualified policy version must
-always be specified.
 
 End of Document