Jsonnet Rendering

Thin wrapper over the _jsonnet C bindings. TLAs are JSON-serialized via json.dumps so jsonnet receives real typed values — ints stay ints, bools stay bools, None becomes jsonnet null. The binding is imported lazily inside render so this module stays safe to import on login nodes without _jsonnet installed.

graphids.config.jsonnet

jsonnet

Jsonnet config rendering via the _jsonnet C bindings.

Evaluates a .jsonnet file with top-level arguments and returns the parsed JSON as a dict. TLAs are passed through tla_codes so jsonnet receives real typed values (ints stay ints, bools stay bools, None becomes jsonnet null).

No torch dep, no package-level side effects — safe to import on login nodes even without _jsonnet installed (the C binding is imported lazily inside render).

JsonnetError

Bases: RuntimeError

Raised when jsonnet evaluation fails.

render

render(jsonnet_path: str | Path, tla: dict[str, Any] | None = None) -> dict[str, Any]

Render a .jsonnet file with top-level arguments.

TLAs are JSON-serialized via json.dumps so jsonnet receives real typed values (ints stay ints, bools stay bools, None → jsonnet null). Raises JsonnetError on evaluation failure or non-object output.

Source code in graphids/config/jsonnet.py

def render(
    jsonnet_path: str | Path,
    tla: dict[str, Any] | None = None,
) -> dict[str, Any]:
    """Render a ``.jsonnet`` file with top-level arguments.

    TLAs are JSON-serialized via ``json.dumps`` so jsonnet receives real
    typed values (ints stay ints, bools stay bools, ``None`` → jsonnet ``null``).
    Raises ``JsonnetError`` on evaluation failure or non-object output.
    """
    import _jsonnet  # noqa: PLC0415  — deferred so module import is safe without the binding

    tla_codes = {k: json.dumps(v) for k, v in tla.items()} if tla else {}
    try:
        raw = _jsonnet.evaluate_file(str(jsonnet_path), tla_codes=tla_codes)
    except RuntimeError as exc:
        raise JsonnetError(f"jsonnet failed for {jsonnet_path}:\n{exc}") from exc

    parsed = json.loads(raw)
    if not isinstance(parsed, dict):
        raise JsonnetError(
            f"jsonnet output for {jsonnet_path} is {type(parsed).__name__}, expected object"
        )
    return parsed