Behaviour for defining custom service data catalogs with additional local graphs.

DCATR.ServiceData manages service-local graphs that are not part of the distributed repository (e.g., configuration, working graphs, service-specific metadata). This behaviour enables applications to create specialized service data catalogs with custom local graphs.

Graph Structure

ServiceData contains:

• manifest - Service configuration (ServiceManifestGraph)
• working_graphs - Temporary/experimental graphs local to the service
• system_graphs - Service-level metadata and operational graphs

Callbacks

• system_graphs/1 - Returns service-level system graphs
• working_graphs/1 - Returns service-local working graphs

Inherits from DCATR.Directory.Type:

• DCATR.Directory.Type.graphs/1, DCATR.Directory.Type.directories/1

Inherits from DCATR.GraphResolver:

• DCATR.GraphResolver.resolve_graph_selector/2

Standard Selectors

• :service_manifest - Service configuration graph

Usage

Custom service data types should use DCATR.ServiceData.Type and define a Grax schema extending DCATR.ServiceData:

defmodule MyApp.ServiceData do
  use DCATR.ServiceData.Type

  schema MyApp.NS.ServiceData < DCATR.ServiceData do
    link cache_graph: MyApp.NS.cache(), type: MyApp.CacheGraph
    link log_graph: MyApp.NS.log(), type: MyApp.LogGraph
  end

  @impl true
  def resolve_graph_selector(data, :cache), do: data.cache_graph
  def resolve_graph_selector(data, :log), do: data.log_graph
  def resolve_graph_selector(data, selector), do: super(data, selector)

  @impl true
  def system_graphs(data) do
    [data.cache_graph, data.log_graph | super(data)]
  end
end

The module automatically provides delegating implementations of all callbacks and convenience functions, all of which are overridable.