GgenIgniter.Engine behaviour (ggen_igniter v26.9.8)

Behaviour every --engine NAME implementation satisfies, so Mix.Tasks.GgenIgniter.Sync dispatches through a lookup table (GgenIgniter.Engine.registry/0) instead of hardcoded, string-pattern-matched function clauses (run_queries("sparql", ...), run_queries("qlever", ...), etc.). Adding a new engine means adding one module + one registry entry, not editing the sync task's dispatch logic.

Two callbacks, split so per-engine setup (e.g. qlever's --store-id lookup and Finch bootstrap) happens once per sync run, not once per query:

prepare!/2 — takes the loaded %RDF.Graph{} and the raw CLI opts, returns whatever context run/2 needs (the graph itself, a loaded store struct, ...).
run/2 — takes that context and one query string, returns [map()] rows (the same row-list contract every engine module already honored before this abstraction existed).

Summary

Callbacks

prepare!(t, keyword)

run(term, t)

Functions

fetch!(name)

Looks up the engine module for name, raising ArgumentError on an unknown engine.

registry()

The --engine name => implementing module map. The single source of truth for valid --engine values.

valid_names()

Valid --engine names, for CLI validation/error messages.

Callbacks

prepare!(t, keyword)

@callback prepare!(
  RDF.Graph.t(),
  keyword()
) :: term()

run(term, t)

@callback run(term(), String.t()) :: [map()]

Functions

fetch!(name)

@spec fetch!(String.t()) :: module()

Looks up the engine module for name, raising ArgumentError on an unknown engine.

Examples

iex> GgenIgniter.Engine.fetch!("sparql")
GgenIgniter.Engine.Sparql

iex> GgenIgniter.Engine.fetch!("nope")
** (ArgumentError) invalid --engine "nope", must be one of: oxigraph, qlever, sparql

registry()

@spec registry() :: %{optional(String.t()) => module()}

The --engine name => implementing module map. The single source of truth for valid --engine values.

Examples

iex> GgenIgniter.Engine.registry()
%{
  "sparql" => GgenIgniter.Engine.Sparql,
  "qlever" => GgenIgniter.Engine.Qlever,
  "oxigraph" => GgenIgniter.Engine.Oxigraph
}

valid_names()

@spec valid_names() :: [String.t()]

Valid --engine names, for CLI validation/error messages.

Examples

iex> GgenIgniter.Engine.valid_names()
["oxigraph", "qlever", "sparql"]