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AAI REST API
++++++++++++

Overview
========

The AAI REST API provides access to the AAI active inventory graph. The
API is largely configured off of models and configuration files. Each
vertex in the graph has an API that can be called separately or, if part
of a tree structure, as a nested element with one or more generations
(parent, grandparent, etc.).

The edges of the graph are provisioned using a relationship list
construct. For PUT methods, a relationship contains the vertex type or
category (related-to) and a list of relationship data which captures the
key pieces of data required to uniquely identify the resource. On a GET
method, the above information and a URL are returned. The URL can be
used to GET all the details of that object. The URL returned is suitable
for retrying failed commands but should not be expected to be cacheable
for very long periods (e.g., the version of the URL may get deprecated
when the release changes).

Concurrency control for AAI is in place. The assumptions made for the
implementation are as follows:

-  A client always gets a resource before updating through PUT or
   deleting it.

-  All resource updates and deletions are done via the AAI REST APIs

-  This solution will apply to PUT and DELETE operations.

-  The resource-version attribute is now in every container

-  The update API is not subject to concurrency control because it is
   only intended to be used by clients who are the definitive source of
   truth for the attributes they are changing. An update through the
   update API will however reset the resource-version so clients using
   PUT and DELETE will not risk updating with stale data.

-  The PATCH REST verb is not subject to concurrency control because it
   is only intended to be used by clients who are the definitive source
   of truth for the attributes they are changing. An update through the
   update API will however reset the resource-version so clients using
   PUT and DELETE will not risk updating with stale data.

How to Use this Document
========================

When you click on the API documentation, you will see the Summary of
APIs broken down by namespace (e.g., cloud-infrastructure, business,
network, service-design-and-creation). You can search for **Tag:**
(matching the explicit case) to move from namespace to namespace through
the Summary.

Search for **Paths** to skip past the Summary section where there will
be more detail about each API. Query parameters are provided here, as
well as links to our error codes.

Search for **Schema definitions** to see the definitions of the
payloads. In your browser URL, you can type /#/definitions/node-name at
the end of the html address to skip directly to a payload definition.

Note that the schema definitions now contain information about the
delete scope of a node (also referenced in this document) and some
related node information (also reference in this document as Edges).

Once AAI has a model and configured it, the AAI development server can
be used to generate sample XML and JSON payloads, according to the
Accept header passed in the request. This is done by calling the
"plural" version of an API followed by the word example (e.g.,
/vserver/vservers/example). This returns a GET result array with one
entry. That single entry can be sent in a PUT request with actual data
(the resource-id does not need to be in the PUT payload as it is on the
URL).

Document Conventions
====================

Information that is largely guidance or aspirational will be show in
gray italicized text. This information should not be relied upon or
referenced at this point except with the understanding that it WILL
change.

**Bold blue text** will be used to cover communication to our clients
that may not be enforced by AAI. The sources of truth (our clients)
populate AAI and are expected to send the correct information, having
applied business rules that live in the client systems.

Deprecation Warnings and History
================================

V11

API retirements:

-  The actions/update API will be retired. Clients must switch to PATCH.
   There is one grandfathered usage for vpe update flows which will be
   retired in v11.

-  The edge tag query will be retired.

Notable attribute and/or valid value changes (generally also impacts
events):

-  The persona-model-id and persona-version will be replaced with
   model-invariant-id (same value as persona-model-id) and
   model-version-id (the UUID of the specific version of a model).
   Persona-model-customization-id will be replaced by
   model-customization-id.

-  The operational-state attribute will be replaced by
   operational-status and the only valid values will be in-service-path
   and out-of-service-path

-  The vpn-binding object will be split in two to reflect more than one
   route-target per binding. The route-target will be a child of
   vpn-binding and some attributes will move from vpn-binding to
   route-target.

-  The following license related attributes will be removed from
   generic-vnf: license-key, entitlement-assignment-group-uuid,
   entitlement-resource-uuid, license-assignment-group-uuid, and
   license-key-uuid due to the introduction of the entitlement and
   license children.

Event Specific:

-  Normal impacts due to renaming or adding attributes, splitting
   objects, etc. Please see swagger documentation for objects of
   interest.

-  In v11, clients that require lineage, children, or relationship
   information need to subscribe to a different DMaaP topic than the
   current one.

Relationship List

-  The related-link will be a URI and thus not contain
   https://{serverroot} (impacts events)

-  Thhe related-link will be used on a PUT as the "first choice" to
   identify the related resource. The relationship-data structure, which
   contains the unordered set of keys, is still an acceptable way to
   relate two objects but, *if both the relationship-data and the
   related-link are passed, and they don't agree, the related-link will
   be used without warning that the data is inconsistent*.

-  The relationship-data will be ignored on PUT.

AAI API Definition
==================

The API structure is composed of:

-  The HTTP command, which indicates the operation to perform

-  The HTTP URI, which defines what object this operation is related to

-  The HTTP version, which MUST be 1.1

Available HTTP commands are:

-  PUT: used to create or update an object

-  DELETE: used to delete an object or a set of objects

-  GET : used to query an object or set of objects

-  PATCH : used to update specific fields owned by the client doing the
   update

The HTTP URI is built according to this pattern:

https://{serverRoot}/{namespace}/{resource}

-  (serverRoot} refers to the server base url: hostname+port+base
   path+version. Port and base path are OPTIONAL but AAI will use port
   8443 and base path aai. The Amsterdam release version will be v11.

-  {namespace} refers to the API namespace. Supported namespaces are
   cloud-infrastructure, business, service-design-and-creation, and
   network

-  {resource} refers to how the object is identified according to the
   namespace specifications.

Example

GET https://{hostname}:8443/aai
/v11/cloud-infrastructure/cloud-regions/cloud-region/{cloud-owner}/{cloud-region-id}

The GET requests support a depth query parameter allowing a query to
stop after it has reached a certain point in the graph. This allows
clients to minimize the data that is returned to them. A depth=0 returns
the resource itself and none of its children.

Data Assumptions
----------------

Given AAI is largely a correlation engine among disparate inventory
types, AAI will accept values as they are sent, without validating the
format or value of the input. It is incumbent upon the source of truth
to provide valid information to AAI.

Clients should do a GET prior to a PUT and change only the data that
they mean to affect. The REST APIs expect the payload passed to replace
the resource in AAI. **This is vital in our concurrency scheme. The
client will be returned an opaque value per entity which needs to be
returned back in the PUT. AAI will reject the PUT or DELETE if the
opaque value doesn't match what AAI has stored for that entity.**

If a leaf has been added to a model in vN+1, and a GET/PUT of a vN
resource is done, AAI should not affect the new leaf (i.e., it should be
left unchanged).

PUT and Lists
-------------

The PUT verb is used to both create and replace a resource. A given
resource may have child resources (e.g., customers have service
subscriptions; tenants have vservers and vservers have volumes).

The following convention will be followed:

If a resource is replaced and there are no tags for children, the
children that exist will be left alone.

If a resource is replaced and there are tags for children, the children
will be replaced by the list passed. If the list is empty, then children
will be deleted.

Note that the relationship list is a type of child resource. The same
conventions are followed. It is especially critical to ensure that you
do not send an incomplete relationship list and therefore remove edges
in the graph. See section 5.10 for more information on relationship
lists.

PATCH
-----

To move towards industry standards and to make our APIs easier to use by
clients who own specific attributes and do not require AAI to enforce
concurrency control around them, the PATCH verb has been introduced.

-  RFC Algorithm implemented JSON Merge PATCH
   `tools.ietf.org/html/rfc7386 <https://tools.ietf.org/html/rfc7386>`__

-  *HTTP Verb = PATCH*

-  PATCH requires a Content-Type of "application/merge-patch+json" in
   your HTTP headers.

-  PATCH does not support XML

-  PATCH does not require a resource version to preform these
   modifications

-  Clients should only send what they wish to modify and whose value
   they "own"

Example:

PATCH \ `https://<hostname>:8443/aai/v11/network/generic-vnfs/generic-vnf/cscf0001v <https://aai-int1.test.att.com:8443/aai/v7/network/generic-vnfs/generic-vnf/cscf0001v>`__

    {

      "vnf-id": "cscf0001v", This key needs to be here but you cannot
modify the key

      "regional-resource-zone": null,

      "ipv4-oam-address": "1.2.3.4"   

}

This payload would result in the generic-vnf with the vnf-id = cscf0001v
having ipv4-oam-address set to "1.2.3.4" and regional-resource-zone
having its value removed from the database.

Referential Integrity
---------------------

AAI is primarily a view to the relationships between customers,
products, services, physical and virtual components, etc. It stores just
the details it needs to be efficient to its tasks and knows how to get
more details if needed.

As such, a transaction sent to AAI may be refused if would break
referential integrity. The referential integrity rules of AAI are still
evolving as we understand the services and customers that will use us.

AAI uses a graph database on a NoSQL data store. The following are true
for AAI:

-  Some vertices are exposed to the outside world through APIs, others
   are internal to how we store the data (i.e., it may look like one
   resource to our customers but it is expressed as more than one vertex
   in our graph)

-  Vertices that are internal to AAI will be deleted when the parent
   vertex is deleted, if deletion of the parent leaves the child vertex
   orphaned

-  Vertices that are exposed need to be managed using specific rules for
   each vertex.

-  Vertices may have more than just parent/child relationships. One
   example is a vserver, which will be owned by a tenant and used by a
   VNF.

Delete Rules
------------

The following options are available as actions to be take upon deletion
of a resource:

-  ERROR\_IF\_ANY\_EDGES – If the resource being deleted has any edges
   at all, an error should be returned

-  ERROR\_IF\_ANY\_IN\_EDGES – if the resource being deleted has any
   edges that point IN towards it, an error should be returned

-  THIS\_NODE\_ONLY – delete the vertex being requested by first
   deleting its edge to other vertices, but do not delete the other
   vertices. Note, the delete will be rejected if the deletion target
   has DEPENDENT children (e.g., tenants that have vservers)

-  CASCADE\_TO\_CHILDREN – cascade the delete through vertices who have
   a parentOf relationship to the vertex being deleted, as long as the
   vertex is orphaned by the delete of its parent

-  ERROR\_4\_IN\_EDGES\_OR\_CASCADE – error if there are any in edges
   and, if not, cascade to children

Security
--------

All REST APIs must be called using https.

The current release is configured to support BasicAuth. 2-way SSL using
client certificates should be configured for production deployments or
as needed.

Headers
-------

The following will be used for logging and interface diagnostic
purposes.

-  X-FromAppId Unique Application ID assigned to the user of these APIs

-  X-TransactionId Unique ID that identifies an API request

The X-FromAppId will be assigned to each application by the AAI team.
The X-TransactionId must be unique to each transaction within the
context of an X-FromAppId.

OpenECOMP components that call AAI use the Java UUID class to generate
unique ids for X-TransactionId.

The Accept header should be set to either application/json or
application/xml.

+-------------------------------+---------------+
| Client                        | X-FromAppId   |
+===============================+===============+
| Policy                        | Policy        |
+-------------------------------+---------------+
| Master Service Orchestrator   | MSO           |
+-------------------------------+---------------+
| SDN Controller                | SDNC          |
+-------------------------------+---------------+
| Application Controller        | APPC          |
+-------------------------------+---------------+

Response Codes and Error Handling
---------------------------------

HTTP response codes and error codes are described in the API
documentation.

URLs Sent To and Retrieved From AAI
-----------------------------------

AAI receives URLs from clients that point back to that client in order
to get more details about the data sent to AAI. AAI expects the URLs
sent by clients (e.g., self links) to be URL encoded (UTF-8) and AAI
will store them unchanged.

URLs that AAI constructs that point to AAI resources will be returned
URLEncoded (UTF-8) to clients. This affects URLs in relationship lists
and search results.

AAI expects space to be %20, and not plus(+).

The Relationship-List
---------------------

The REST interface does not lend itself to creating more than
parent-child relationships and the backend structure of AAI is a graph.
A goal of AAI is to do as little coding as possible to introduce a new
service into the service design and creation environment.

To that end, we've introduced a relationship-list structure. AAI will
ask its clients to provide certain data in the relationship-list
structure.

Each relationship has a related-to attribute and a list of key/value
pairs. The related-to attribute identifies the node type that the
resource being acted on is to be related to using the data in the
key/value pairs. AAI will encode a set of rules for each resource type
to verify that only valid edges are being made. AAI will keep the name
of the edge itself, the directionality and cardinality, and the edge
attributes within its own logic.

If an attempt is made to add a relationship to a node that doesn't exist
(e.g., from a vserver to a vnf, and the vnf doesn't exist), a unique
message Id (3003) will be returned with a specific error code
(ERR.5.4.6129). Arguments will tell the client which node type was
missing (e.g., generic-vnf) and the key data for that node type
(generic-vnf.vnf-id).

Single relationships can be PUT to the graph in the following way:

https://{serverRoot}/{namespace}/{resource}
/relationship-list/relationship

or

https://{hostname}:8443/aai/v11/cloud-infrastructure/pservers/pserver/pserver-123456789-01/p-interfaces/p-interface/p-interface-name-123456789-01/l-interfaces/l-interface/l-interface-name-123456789-01/relationship-list/relationship

with a payload containing the relationship information.

XML:

<relationship xmlns="http://org.openecomp.aai.inventory/v11">

<related-to>logical-link</related-to>

<relationship-data>

    <relationship-key>logical-link.link-name</relationship-key>

    <relationship-value>logical-link-123456789-01</relationship-value>

</relationship-data>

</relationship>

JSON:

"related-to": "logical-link",

"relationship-data": [

{

    "relationship-key": "logical-link.link-name",

    "relationship-value": " logical-link-123456789-01"

}

]

}

Edges
=====

The following are the properties used for edge definitions. T is true, F
is false

-  From and To are the node types for the ends of the edges.

-  EdgeLabel is the name of the label within the graph.

-  Direction shows the direction of the edge.

-  Multiplicity shows the multiplicity rule between two nodes. This
   helps govern what AAI does when modifying relationships between edges
   using the relationship REST APIs

-  ParentOf indicates whether From is a parent of To.

-  UsesResource specifies whether the From node uses resources of the To
   node, to be able to view the data in the context of "what uses what".

-  hasDelTarget specifies whether to try to delete the To node when the
   From node is deleted.

-  SVC-INFRA (deprecated)

The configuration for different edges supported by the AAI model are
defined in the DbEdgeRules.java class.

Indexed Attributes 
===================

AAI supports query parameters on its indexed attributes.

As an example, if you wanted to GET a tenant by tenant-name, you would
do something like

/aai/vX/cloud-infrastructure/cloud-regions/cloud-region/cloud\_owner\_1/cloud-region\_1/tenants/tenant?tenant-name=value

The properties that are indexed are defined in the aai-schema.

Namespaces
==========

Util Domain
-----------

The util domain is where AAI locates utility functions. There is
currently one utility function, echo, which serves as a ping test that
authenticated authorized clients can call to ensure there is
connectivity with AAI.

The URL for the echo utility is:

https://load-balanced-address:8443/aai/util/echo

If the response is unsuccessful, an error will be returned following the
standard format.

The successful payload returns the X-FromAppId and X-TransactionId sent
by the client.

Successful XML Response Payload
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

<Info>

<responseMessages>

<responseMessage>

<messageId>INF0001</messageId>

<text>Success X-FromAppId=%1 X-TransactionId=%2 (msg=%3) (rc=%4)</text>

<variables>

<variable>XYZ</variable>

<variable>XYZ123</variable>

<variable>Successful health check:OK</variable>

<variable>0.0.0002</variable>

</variables>

</responseMessage>

</responseMessages>

</Info>

Successful JSON Response Payload
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

{"responseMessages": {"responseMessage": [{

"messageId": "INF0001",

"text": "Success X-FromAppId=%1 X-TransactionId=%2 (msg=%3) (rc=%4)",

"variables": {"variable": [

"XYZ",

"XYZ123",

"Successful health check:OK",

"0.0.0002"

]}

}]}}

Cloud Infrastructure Domain
---------------------------

The Cloud Infrastructure domain (cloud-infrastructure) represents the
assets managed within a cloud infrastructure site. This includes the
physical servers, tenants, vservers and cloud-region.

Network Domain
--------------

The network namespace contains virtual and physical network resources as
well as connection resources such as physical links, logical links, etc.

Business Domain
---------------

The business namespace captures customers, service subscriptions, and
service instances. This domain is immature and will be evolving as
service design and creation starts to gel.

Service Design and Creation
---------------------------

The service design and creation namespace captures data we invented
based on what we thought SDC would eventually provide.

To date, there are only five containers:

1. Service-capabilities capture the pairings of service to resources.

2. Service captures the service model instances and this will be
   deprecated in the future as things mature

3. Models captures model definitions (subgraph definitions using the AAI
   widgets)

4. named-queries capture subgraph definitions that allow different data
   to be retrieved for a given type of asset