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Configuration: YAML loader

Container.from_yaml(path) is the YAML counterpart of from_toml and from_json. Unlike the TOML and JSON loaders, it requires the optional yaml extra which pulls in PyYAML:

pip install tripack-container[yaml]

Without the extra, the call raises ConfigurationError pointing at this install command rather than the bare ModuleNotFoundError.

modules:
  - my_app.modules.CacheModule

bindings:
  - token: my_app.services.Clock
    factory: my_app.factories.make_clock
    lifecycle: singleton

  - token: my_app.services.Session
    factory: my_app.factories.make_session_async
    lifecycle: scoped
    async_factory: true

  - token: my_app.services.App
    factory: my_app.factories.make_app
    lifecycle: transient
    auto_inject: true

from tripack_container import Container

container = Container.from_yaml("config.yaml")

Parser safety

The loader uses yaml.safe_load, which only parses the standard YAML scalar / mapping / sequence types. It will NOT instantiate arbitrary Python objects from !!python/object tags, so a malicious config file cannot use the loader as a remote-code- execution vector. This is the right default for declarative wiring; users that genuinely need full-loader behavior should parse the file themselves and call Container.from_dict-style helpers (not provided in this release).

Schema parity

The YAML schema is identical to the TOML and JSON ones; only the serialization format differs. Each [[bindings]] table becomes one entry in the YAML bindings: sequence, and the optional flags carry the same names and types.

Errors

  • Missing extra: pip install tripack-container[yaml] required; ConfigurationError with an install hint.
  • Malformed YAML: yaml.YAMLError wrapped into ConfigurationError with the parser's message attached.
  • Invalid structure / unknown lifecycle / non-importable factory: same errors as TOML / JSON, since validation runs through the shared build_container_from_config helper.

Why an optional dependency?

TOML and JSON are in the standard library (3.11+); adding PyYAML as a hard dependency would bloat the install footprint for users who do not need YAML. The optional extra keeps the core tripack-container install small and lets YAML users opt in.