module bbf-grpc-client {

    yang-version 1.1;

    namespace "urn:bbf:yang:bbf-grpc-client";

    prefix bbf-grpcc;

    import bbf-yang-types {
      prefix bbf-yang;
    }
    import ietf-inet-types {
      prefix inet;
    }
    import ietf-yang-types {
      prefix yang;
    }

    organization
      "Broadband Forum <https://www.broadband-forum.org>
     SDN/NFV Work Area";

    contact
      "Comments or questions about this Broadband Forum YANG module
     should be directed to <mailto:help@broadband-forum.org>.

     Editor:      Tim Carey, Nokia

     Editor:      Jeff Hartley, Commscope

     WA Director: Mengmeng Li, China Mobile

     WA Director: Bruno Cornaglia, Vodafone";

    description
      "This module contains a collection of YANG definitions for
     supporting the Broadband Forum requirements for gRPC client
     functionality as described in TR-451.

     Copyright (c) 2019-2022, Broadband Forum

     Redistribution and use in source and binary forms, with or
     without modification, are permitted provided that the following
     conditions are met:

     1. Redistributions of source code must retain the above copyright
        notice, this list of conditions and the following disclaimer.

     2. Redistributions in binary form must reproduce the above
        copyright notice, this list of conditions and the following
        disclaimer in the documentation and/or other materials
        provided with the distribution.

     3. Neither the name of the copyright holder nor the names of its
        contributors may be used to endorse or promote products
        derived from this software without specific prior written
        permission.

     THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
     CONTRIBUTORS \"AS IS\" AND ANY EXPRESS OR IMPLIED WARRANTIES,
     INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
     MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
     DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
     CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
     NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
     LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
     CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
     STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
     ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

     The above license is used as a license under copyright only.
     Please reference the Forum IPR Policy for patent licensing terms
     <https://www.broadband-forum.org/ipr-policy>.

     Any moral rights which are necessary to exercise under the above
     license grant are also deemed granted under this license.

     This version of this YANG module is part of TR-451; see
     the TR itself for full legal notices.";

    revision "2022-06-07" {
      description
        "Issue 1.
       * Approval Date:    2022-06-07.
       * Publication Date: 2022-06-07.";
      reference
        "TR-451: vOMCI Specification
        	<https://www.broadband-forum.org/technical/download/
        		 TR-451_Issue-1.pdf>";

    }


    feature grpc-client {
      description
        "Indicates that the client supports gRPC as a message
       transport protocol.";
    }

    feature connection-backoff {
      description
        "Indicates that the server supports managing how a client
       reconnects to a remote endpoint, after discovering
       its connection to the remote endpoint has dropped.";
    }

    grouping grpc-client {
      description
        "Data nodes for configuring a gRPC client, including the IP
       address and port number it initiates a connection to.

       Note that this grouping uses fairly typical descendant node
       names such that a stack of 'uses' statements will have name
       conflicts. It is intended that the consuming data model will
       resolve the issue (e.g., by wrapping the 'uses' statement in a
       container). This model purposely does not do this itself so as
       to provide maximum flexibility to consuming models.";
      container channel {
        description
          "The gRPC channel properties.";
        leaf ping-interval {
          type uint32 {
            range "0..max";
          }
          units "seconds";
          default "300";
          description
            "Sets the amount of time after which a ping request is sent.
           A value of 0 disables pings from being sent.";
        }
      }  // container channel

      container connection-backoff {
        if-feature bbf-grpcc:connection-backoff;
        description
          "The connection backoff directs how a client reconnects to a
         remote endpoint after discovering its connection to the
         remote endpoint has dropped.";
        reference
          "github.com/grpc/grpc/blob/master/doc/connection-backoff.md.";

        leaf enable {
          type boolean;
          default "true";
          description
            "If 'true', connection-backoff is enabled.";
        }

        leaf initial-backoff {
          type uint16 {
            range "1..max";
          }
          units "seconds";
          default "30";
          description
            "The initial wait period after the first failure before
           retrying.";
        }

        leaf min-connect-timeout {
          type uint16 {
            range "1..max";
          }
          units "seconds";
          default "20";
          description
            "The minimum time to wait for the connection attempts.";
        }

        leaf multiplier {
          type decimal64 {
            fraction-digits 2;
          }
          default "1.60";
          description
            "The factor with which to multiply the backoff after a
           failed retry.";
        }

        leaf jitter {
          type decimal64 {
            fraction-digits 2;
          }
          default "0.20";
          description
            "The factor with which to randomize the backoff.";
        }

        leaf max-backoff {
          type uint16 {
            range "1..max";
          }
          default "10";
          description
            "The number of times the client tries to connect to a
           specific endpoint before moving on to the next endpoint
           in the list (round robin).";
        }
      }  // container connection-backoff
    }  // grouping grpc-client

    grouping grpc-client-transport {
      description
        "The gRPC specific configuration for the connection.";
      container grpc-client {
        if-feature bbf-grpcc:grpc-client;
        description
          "A wrapper around the gRPC client parameters to avoid name
         collisions.";
        uses bbf-grpcc:grpc-client;

        list access-point {
          key "name";
          min-elements 1;
          ordered-by user;
          description
            "A user-ordered list of access points that the client will
           attempt to connect to in the specified sequence. Defining
           more than one enables high-availability.";
          leaf name {
            type bbf-yang:string-ascii64;
            description
              "An arbitrary name for the access point.";
          }

          container grpc-transport-parameters {
            description
              "gRPC agent transport parameters.";
            choice tcp-client-options {
              description
                "Replicate some pre-standard IETF client/server
               options in-file, and provide a place to add IETF
               client/server stack options post-standard in the
               future.";
              container remote-port {
                description
                  "The remote port identified by a client.";
                leaf remote-port {
                  type inet:port-number;
                  default "8443";
                  description
                    "The client will attempt to connect to the
                     common port value for 'grpc' (8443) if no
                     value is specified.";
                }
              }  // container remote-port
            }  // choice tcp-client-options
          }  // container grpc-transport-parameters

          notification remote-endpoint-status-change {
            description
              "A notification traceable to a client remote-endpoint
             and access-point. This notification is sent when a
             remote-endpoint is connected or disconnected.";
            leaf connected {
              type boolean;
              mandatory true;
              description
                "New remote-endpoint status.";
            }

            leaf last-changed {
              type yang:date-and-time;
              mandatory true;
              description
                "The system date and time when the remote-endpoint was
               connected or disconnected.";
            }
          }  // notification remote-endpoint-status-change
        }  // list access-point
      }  // container grpc-client
    }  // grouping grpc-client-transport
  }  // module bbf-grpc-client