"""A PEtab ``Model`` adapter for BNGL, registered into ``petab`` at runtime (ADR-0026).
``petab`` 0.8.x ships only ``sbml``/``pysb`` model loaders, so ``petablint`` cannot
load a ``language: bngl`` problem -- it dies at model-load before any table check.
:class:`BnglModel` is the missing loader: a :class:`petab.v1.models.model.Model`
backed by PyBNF's own stdlib BNGL reader (:mod:`pybnf.petab._bngl`), so the PEtab v2
exporter's emitted problems validate at *model* level (the ~5 model-cross checks
ADR-0025 had to exclude), with no BNG2.pl needed for the enumeration.
This is **Step A** of issue #420 -- a local reference implementation. :func:`register_bngl`
teaches a running ``petab`` about BNGL by rebinding ``petab.v2.core.model_factory``
(petab's factory is a hardcoded ``if/elif`` with no plugin hook). **Step B** upstreams
the same class to ``PEtab-dev/libpetab-python`` as a peer of ``PySBModel``; once that
lands, :func:`register_bngl` collapses to a no-op.
Validation needs only *parsing*, so every ABC method is backed by the parsed entity
sets -- except :meth:`BnglModel.is_valid`, which shells out to ``BNG2.pl --check`` (the
real validator) when a BNG2.pl is locatable, and degrades gracefully to ``True`` when
it is not. This module imports ``petab`` and is therefore **not** imported by
``pybnf.petab.__init__``; it is reached only from the test tier / an explicit
``register_bngl()`` call, keeping core dependency-free (ADR-0025).
"""
import os
import shutil
import subprocess
from pathlib import Path
from petab.v1.models.model import Model
from ._bngl import parse_model
#: BNGL model type, as used in a PEtab v2 yaml file as ``language``.
MODEL_TYPE_BNGL = 'bngl'
[docs]
class BnglModel(Model):
"""PEtab ``Model`` wrapper for a BNGL model (validation-grade; no simulation)."""
type_id = MODEL_TYPE_BNGL
def __init__(self, entities, model_id, path=None):
super().__init__()
self._entities = entities
self._model_id = model_id
self._path = Path(path) if path is not None else None
[docs]
@staticmethod
def from_file(filepath_or_buffer, model_id=None, base_path=None):
path = Path(filepath_or_buffer)
if base_path is not None and not path.is_absolute():
path = Path(base_path) / path
text = path.read_text(encoding='utf-8', errors='replace')
return BnglModel(parse_model(text), model_id=model_id or path.stem, path=path)
[docs]
def to_file(self, filename=None):
target = Path(filename) if filename is not None else self._path
if target is None:
raise ValueError("No filename given and this BnglModel has no source path.")
target.write_text(self._entities.text, encoding='utf-8')
@property
def model_id(self):
return self._model_id
# -- parameters ---------------------------------------------------------
[docs]
def get_parameter_ids(self):
return list(self._entities.parameters)
[docs]
def get_parameter_value(self, id_):
try:
rhs = self._entities.parameters[id_]
except KeyError as e:
raise ValueError(f"Parameter {id_} does not exist.") from e
try:
return float(rhs)
except ValueError as e:
raise NotImplementedError(
f"Parameter '{id_}' has an expression value '{rhs}'. Evaluating a "
f"BNGL parameter expression needs BNG2.pl/network generation, which "
f"is out of scope for the validation-grade BnglModel (ADR-0026)."
) from e
[docs]
def get_free_parameter_ids_with_values(self):
out = []
for name, rhs in self._entities.parameters.items():
try:
out.append((name, float(rhs)))
except ValueError:
continue # an expression-valued parameter has no validation-grade value
return out
[docs]
def get_valid_parameters_for_parameter_table(self):
return list(self._entities.parameters)
# -- model-entity namespaces (verified against BNG2.pl; ADR-0026) -------
[docs]
def has_entity_with_id(self, entity_id):
"""Any declared identifier: the full BNGL model-entity namespace."""
e = self._entities
return (entity_id in e.parameters
or entity_id in e.observable_names
or entity_id in e.function_names
or entity_id in e.molecule_type_names
or entity_id in e.compartment_names
or entity_id in e.seed_species)
[docs]
def get_valid_ids_for_condition_table(self):
return list(self._entities.parameters) + list(self._entities.compartment_names)
[docs]
def is_state_variable(self, id_):
"""A species. At validation grade, only the concrete ``seed species`` are known
(the full set is a network-generation product, out of scope; ADR-0026)."""
return id_ in self._entities.seed_species
# -- validity -----------------------------------------------------------
[docs]
def is_valid(self):
"""``BNG2.pl --check`` (real validation, no network gen) when locatable, else
``True`` -- never a false failure where no BNG backend is available."""
bng2 = _locate_bng2()
if bng2 is None or self._path is None:
return True
try:
result = subprocess.run(
[bng2, '--check', str(self._path)],
capture_output=True, text=True, timeout=120,
cwd=str(self._path.parent),
)
except (OSError, subprocess.SubprocessError):
return True # a tooling hiccup must not masquerade as an invalid model
return result.returncode == 0
def _locate_bng2():
"""A path to ``BNG2.pl`` via ``BNGPATH`` or ``PATH``, or ``None`` if unavailable."""
bngpath = os.environ.get('BNGPATH')
if bngpath:
candidate = Path(bngpath) / 'BNG2.pl'
if candidate.is_file():
return str(candidate)
return shutil.which('BNG2.pl')
[docs]
def register_bngl():
"""Teach a running ``petab`` to load ``language: bngl`` models via :class:`BnglModel`.
Idempotent and additive: rebinds ``petab.v2.core.model_factory`` to route ``bngl``
to :class:`BnglModel` and delegate every other language to the captured original
(so ``sbml``/``pysb`` are untouched), and registers ``'bngl'`` as a known model
type. A guarded permanent rebind (no teardown) -- the temporary local stand-in for
Step B's upstream loader (ADR-0026).
"""
import petab.v1.models as _models
import petab.v2.core as _v2core
# If petab already supports BNGL natively (a libpetab-python build that
# shipped the upstream loader -- #420 Step B), do nothing: its model_factory
# already routes 'bngl' to a native BnglModel that supersedes this local
# stand-in. This is the "collapse to a no-op" ADR-0026 anticipated; it is
# what lets the exporter tests dogfood the native loader. We distinguish
# native support (bngl present, our wrapper never installed) from our own
# prior registration (the sentinel below) so re-entry stays idempotent.
already_registered = hasattr(_v2core, '_pybnf_orig_model_factory')
if MODEL_TYPE_BNGL in _models.known_model_types and not already_registered:
return
_models.known_model_types.add(MODEL_TYPE_BNGL)
original = getattr(_v2core, '_pybnf_orig_model_factory', None)
if original is None:
original = _v2core.model_factory
_v2core._pybnf_orig_model_factory = original
def _model_factory(filepath_or_buffer, model_language, model_id=None, base_path=None):
if model_language == MODEL_TYPE_BNGL:
return BnglModel.from_file(
filepath_or_buffer, model_id=model_id, base_path=base_path)
return original(
filepath_or_buffer, model_language, model_id=model_id, base_path=base_path)
_v2core.model_factory = _model_factory
