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EngineServiceLoader

What it is​

  • A small loader that instantiates engine services based on module-declared service dependencies.
  • Uses an EngineConfiguration to load() only the services that are needed, then wires them via IEngine.Services.wire_services().

Public API​

  • class EngineServiceLoader
    • __init__(configuration: EngineConfiguration)
      • Stores the engine configuration used to load services.
    • load_services(module_dependencies: Dict[str, ModuleDependencies]) -> IEngine.Services
      • Collects requested service types from module_dependencies.
      • Loads only those services (plus any implicit dependencies defined in SERVICES_DEPENDENCIES).
      • Calls wire_services() on the resulting IEngine.Services and returns it.

Configuration/Dependencies​

  • Requires:
    • EngineConfiguration with services.<service>.load() factories for:
      • object_storage, triple_store, vector_store, secret, bus, kv, email, cache
    • module_dependencies: Dict[str, ModuleDependencies] where each ModuleDependencies.services is a list of service types (classes).
  • Implicit service dependencies (auto-loaded when needed):
    • If TripleStoreService is requested, BusService will also be loaded.
    • (Defined by SERVICES_DEPENDENCIES = { TripleStoreService: [BusService] })

Usage​

from naas_abi_core.engine.engine_loaders.EngineServiceLoader import EngineServiceLoader
from naas_abi_core.engine.engine_configuration.EngineConfiguration import EngineConfiguration
from naas_abi_core.services.triple_store.TripleStoreService import TripleStoreService
from naas_abi_core.module.Module import ModuleDependencies

config = EngineConfiguration(...)  # must provide .services.*.load()
loader = EngineServiceLoader(config)

module_deps = {
    "my_module": ModuleDependencies(services=[TripleStoreService]),
}

services = loader.load_services(module_deps)

# services.triple_store is loaded, and services.bus is also loaded due to dependency

Caveats​

  • Only dependencies encoded in SERVICES_DEPENDENCIES are automatically loaded (currently only TripleStoreService -> BusService).
  • Services not requested (directly or via SERVICES_DEPENDENCIES) are set to None in IEngine.Services.