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. It is not clear what HTTP Operation should be used for "Deltee" but RestFul API design would preclude a body for delete operations.See also CPS-577: Prepare the request from client and send write request to dmi-plugin
#IssueNotesDecision
1How will hostname and port be provided when dmiPlugin register itself and its list of cmHandles with NCMP

The team thinks that the information should instead be provided in the form of a ‘host-name’ and a ‘port’  (there was some debate on service-name v. host-name but it was settled on host-name)


e.g. "dmiPlugin" : { <host-name>,  <port> }


Where the host-name is unique. (the DB might assign an internal unique ID for each entry but that is just for indexing and x-referencing in a relation DB and this ID is not to be used/ exposed externally)

Instead of using ‘host-names’ and ‘ports’ parameters between java applications when in the cloud all we need is ‘service-names’ . The mapping of service-names to hosts and ports is done as part of the cloud configuration, in our case Kubernetes. And these are dynamic! The client application can then use a simple dns-lookup to connect to an instance of the service.

Using service names also allows any plugin to use implement scaling as they see fit e.g. partitioning


For the ONAP DMI Plugin which initial have only 1 instance we can simply hard-code the service-name and us the same name in the Kubernetes configuration e.g. “onap.cps.dmiPlugin"
2Additional information in request body duplicates cmHandleId this is redundant informationSuggested to remove from request body to avoid possible error scenarios.Only the one with the additionalInformation is needed and remove body
3No need for Sync method, this is basic standard read operation at the root level for that cmHandle

4Use include 'location' property when request yang-module sourcesSuggestion: do include it in the request but allow dmiPlugin to decide to use it or now. Location (this leaf is called schema in older RFC7895) is not mandatory to support in YANG library and nodes may not include it. Another alternative presumably used also by ODL itself is the <get-schema> RPC. The key difference is that the YANG module definition is sent directly over the NETCONF channel, not requiring separate file servers and clients. So this is maybe one more reason that the ONAP DMI plugin currently doesn’t need the location attribute.

Location is not needed for any plugin and could only lead to ambiguity therefore will NOT be included in this request

5Inconsistent use of "Operation" and/or HTTP Methods to distinguish write operationsCurrently this page proposes to use "Operation=update" request body parameter for restconf "Replace" and "Patch" operations and use the HTTP (RESTFul) operation to distinguish between them. It also proposes to use PUT  HTTP for Read and Delete operations (sad) Basically a very confusing an unintuitive use of HTTP operations to distinguish ambiguous operations that instead easily could be defined by just using the 'operation' field in the request body.

Proposal Toine: For Consistent (restful) design I would suggest to think as the operation to DMI-Plugin (always with body) as "creating a new order to do something" toward DMI-Plugin. Ie always a HTTP POST (or PUT?) operation. The "operation " in the body can simple be extended to include both "update" and "patch" as required

. If the 'operation' is NOT supplied "read" wil be assumed as the default operation

See also CPS-NCMP - DMI - SDNC Request and Response Mapping


Proposal agreed by stakeholders in meeting  

  • Only 'POST' method needs to be supported
  • use term 'Update' instead of 'replace'

DMI URI

Below table shows the proposed interface, actual implementation might deviate from this but can be accessed from

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NCPS-NCMP - DMI Plugin Write Request Flow

See CPS-577: Prepare the request from client and send write request to dmi-pluginNCMP - DMI - SDNC Request and Response Mapping

Datastore

If the cmhandle metadata indicates that data is not synched in CPS then the request is forwarded to the dmiPlugin

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  1. The URI prefix is /dmi instead of /ncmp.
  2. For non-passthrough datastores, the resource path will be converted from cpsPath to RESTConfPath

  3. The body for each request will contain additional information and any data provided on the NCMP interface (write operations) will be embedded in a larger JSON structure as described in example below.

  4. Since all requests will have a message body, in some cases the HTTP method will be different to allow passing data. Thus PUT (or POST ) can be used, the actual operation will be read from the body.

Excerpt

Request Format for Data Access

Code Block
languagexml
titlerequest body
{
  “operation”: “<operation>”,         // Valid operations are: “create”, “read”, “update”, “patch” and “delete”.
                                      
 // For update "dataType": "<dataType>", replace and patch is distinguished by the HTTP method (PUT or PATCH).
  "dataType": "<dataType>",// e.g. "application/yang.data"

    “data”: {                           // Embedded data as a String.
    <data>                            // required for create and update operations. Optional filter-data for read-operations
  },

  “cmHandleProperties”: {           // Additional properties for CM handle previously added by DMI plugin and stored in NCMP.
    <properties>
  }
}


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