Need ODM SDF Syntax to Cover Thing / Interface Object / Trait Version Mappings

[gerickson]

In Weave Data Language (WDL), interfaces are equivalent to ODM "things" and describe an abstract, contractual publish/subscribe interface for generic ecosystem interactions. Over time, the definition of the interface may evolve and its version incremented as those changes occur. To the extent that changes in the interface need to be bound to specific versions of one or more underlying traits (objects), WDL provides a construct in the form of the version_map decoration to specify those dependencies.

To be expressed in ODM SDF losslessly, a syntax construct for representing this version mapping, when present, is required.

Relevant Example Schema Input Files

• weave/iface/lock/voice_assistant_lock_iface.proto

Missing or Unmapped WDL-to-ODM SDF Syntax

• version_map
  • This is an array of dictionaries specifying which specific versions of the traits comprising the interface are depended upon for a particular interface version. The dictionaries contain two keys: parent_version and dependent_version_list. Note that not all traits specified in the interface need be specified in the version map; they need only be specified if there are specific version requirements.
  • dependent_version_list
    • This is an array of dictionaries specifying the trait and version thereof that is to be bound for a particular interface version. The dictionaries contain two keys: name and version.
    • name
      The name of the trait on which the specific parent_version of this interface depends.
    • version
      The version of the named trait on which the specific parent_version of this interface depends.
  • parent_version
    • The specific version of the interface for which trait dependencies are being specified.

Example Input WDL

message BasicLockIface {
    option (wdl.message_type) = IFACE;

    option (wdl.iface) = {
        stability: ALPHA,
        vendor_id: 0x0000,
        version: 1
  };

    weave.trait.security.BoltLockTrait          lock             = 1;

    weave.trait.security.BoltLockSettingsTrait  lock_settings    = 2;

    weave.trait.auth.ApplicationKeysTrait       application_keys = 3;
}

message VoiceAssistantLockIface {
    option (wdl.message_type) = IFACE;

    option (wdl.iface) = {
        stability: ALPHA,
        vendor_id: NEST,
        version: 1,
        version_map: [
            {
                parent_version: 1, dependent_version_list: [
                    { name: "weave.trait.security.BoltLockTrait", version: 2 }
                ]
            }
        ]
    };

    weave.trait.security.BoltLockTrait bolt_lock = 1;
}

[mjkoster]

This should be resolved using the same mechanism as #67 so it seems to be a duplicate

[gerickson]

Agreed that we can hopefully cover the requirement with the same approach. Not sure why Google didn't do so originally.

[asoloway64]

F2F4: OneDM Language and OneDM data models shall both be versioned (i.e. a "release tag" in github). When the models are "released", both the language and the models get the same "release tag". Changes to the language shall not require updates to the existing models. The language can be released without re-releasing the models.

[asoloway64]

F2F4: Version negotiation would be a function of protocol binding and is not represented in the schema. The preferred way to adapt to changes in the data model is through feature and object discovery.

[gerickson]

What's the F2F4 recommendation for lossless representation in SDF for ecosystems like WDL?