ENH: Add Provider base class

src/fmu/dataio/_metadata.py

@@ -25,6 +25,7 @@
 )
 from .datastructure._internal import internal
 from .datastructure.meta import meta
+from .exceptions import InvalidMetadataError
 from .providers._filedata import FileDataProvider
 from .providers._fmu import FmuProvider
 from .providers.objectdata._provider import objectdata_provider_factory
@@ -70,21 +71,24 @@ def _get_objectdata_provider(
     return objdata
 
 
-def _get_filedata_provider(
+def _get_meta_filedata(
     dataio: ExportData,
     obj: types.Inferrable,
     objdata: ObjectDataProvider,
     fmudata: FmuProvider | None,
     compute_md5: bool,
-) -> FileDataProvider:
+) -> FileDataProvider | None:
     """Derive metadata for the file."""
-    return FileDataProvider(
-        dataio=dataio,
-        objdata=objdata,
-        runpath=fmudata.get_runpath() if fmudata else None,
-        obj=obj,
-        compute_md5=compute_md5,
-    )
+    try:
+        return FileDataProvider(
+            dataio=dataio,
+            objdata=objdata,
+            runpath=fmudata.get_runpath() if fmudata else None,
+            obj=obj,
+            compute_md5=compute_md5,
+        ).get_metadata()
+    except InvalidMetadataError:
+        return None
 
 
 def _get_meta_objectdata(
@@ -97,6 +101,13 @@ def _get_meta_objectdata(
     )
 
 
+def _get_meta_fmu(fmudata: FmuProvider) -> internal.FMUClassMetaData | None:
+    try:
+        return fmudata.get_metadata()
+    except InvalidMetadataError:
+        return None
+
+
 def _get_meta_access(dataio: ExportData) -> meta.SsdlAccess:
     return meta.SsdlAccess(
         asset=meta.Asset(
@@ -166,25 +177,25 @@ def generate_export_metadata(
         meta_existing = read_metadata_from_file(obj)
 
     objdata = _get_objectdata_provider(obj, dataio, meta_existing)
-    filedata = _get_filedata_provider(dataio, obj, objdata, fmudata, compute_md5)
-
     masterdata = dataio.config.get("masterdata")
 
     metadata = internal.DataClassMeta(
         schema_=TypeAdapter(AnyHttpUrl).validate_strings(SCHEMA),  # type: ignore[call-arg]
         version=VERSION,
         source=SOURCE,
         class_=objdata.classname,
-        fmu=fmudata.get_metadata() if fmudata else None,
+        fmu=_get_meta_fmu(fmudata) if fmudata else None,
         masterdata=_get_meta_masterdata(masterdata) if masterdata else None,
         access=_get_meta_access(dataio),
         data=_get_meta_objectdata(objdata),
-        file=filedata.get_metadata(),
+        file=_get_meta_filedata(dataio, obj, objdata, fmudata, compute_md5),
         tracklog=generate_meta_tracklog(),
         display=_get_meta_display(dataio, objdata),
-        preprocessed=_get_meta_preprocessed_info(dataio)
-        if dataio.fmu_context == FmuContext.PREPROCESSED
-        else None,
+        preprocessed=(
+            _get_meta_preprocessed_info(dataio)
+            if dataio.fmu_context == FmuContext.PREPROCESSED
+            else None
+        ),
     ).model_dump(mode="json", exclude_none=True, by_alias=True)
 
     if skip_null:

src/fmu/dataio/exceptions.py

@@ -0,0 +1,5 @@
+from __future__ import annotations
+
+
+class InvalidMetadataError(Exception):
+    """Raised when valid metadata cannot be generated or returned."""

src/fmu/dataio/providers/_base.py

@@ -0,0 +1,18 @@
+from abc import ABC, abstractmethod
+
+from pydantic import BaseModel
+
+
+class Provider(ABC):
+    @abstractmethod
+    def get_metadata(self) -> BaseModel:
+        """Get the Pydantic model of the metadata that a provider is meant
+        to provide.
+
+        Returns:
+            BaseModel: The Pydantic BaseModel representing metadata.
+
+        Raises:
+            InvalidMetadataError: When the derived metadata is invalid.
+        """
+        raise NotImplementedError

src/fmu/dataio/providers/_filedata.py

@@ -19,6 +19,8 @@
 )
 from fmu.dataio.datastructure.meta import meta
 
+from ._base import Provider
+
 logger: Final = null_logger(__name__)
 
 if TYPE_CHECKING:
@@ -34,7 +36,7 @@ class ShareFolder(str, Enum):
 
 
 @dataclass
-class FileDataProvider:
+class FileDataProvider(Provider):
     """Class for providing metadata for the 'files' block in fmu-dataio.
 
     Example::

src/fmu/dataio/providers/_fmu.py

@@ -42,6 +42,9 @@
 from fmu.dataio._logging import null_logger
 from fmu.dataio.datastructure._internal import internal
 from fmu.dataio.datastructure.meta import meta
+from fmu.dataio.exceptions import InvalidMetadataError
+
+from ._base import Provider
 
 if TYPE_CHECKING:
     from uuid import UUID
@@ -91,7 +94,7 @@ def keyname(self) -> str:
 
 
 @dataclass
-class FmuProvider:
+class FmuProvider(Provider):
     """Class for getting the run environment (e.g. an ERT) and provide metadata.
 
     Args:
@@ -165,13 +168,12 @@ def get_runpath(self) -> Path | None:
         """Return runpath for a FMU run."""
         return self._runpath
 
-    def get_metadata(self) -> internal.FMUClassMetaData | None:
+    def get_metadata(self) -> internal.FMUClassMetaData:
         """Construct the metadata FMU block for an ERT forward job."""
         logger.debug("Generate ERT metadata...")
 
         if self._casepath is None or self.model is None:
-            logger.info("Can't return metadata, missing casepath or model description")
-            return None
+            raise InvalidMetadataError("Missing casepath or model description")
 
         case_meta = self._get_fmucase_meta()
 

tests/test_units/test_fmuprovider_class.py

@@ -10,6 +10,7 @@
 # from conftest import pretend_ert_env_run1
 from fmu.dataio._definitions import FmuContext
 from fmu.dataio.providers._fmu import RESTART_PATH_ENVNAME, FmuEnv, FmuProvider
+from fmu.dataio.exceptions import InvalidMetadataError
 
 logger = logging.getLogger(__name__)
 
@@ -27,7 +28,10 @@ def test_fmuprovider_no_provider():
         include_ertjobs=False,
         workflow=WORKFLOW,
     )
-    assert myfmu.get_metadata() is None
+    with pytest.raises(
+        InvalidMetadataError, match="Missing casepath or model description"
+    ):
+        myfmu.get_metadata()
 
 
 def test_fmuprovider_model_info_in_metadata(fmurun_w_casemetadata):
@@ -47,8 +51,11 @@ def test_fmuprovider_model_info_in_metadata(fmurun_w_casemetadata):
         fmu_context=FmuContext.REALIZATION,
         workflow=WORKFLOW,
     )
-    meta = myfmu.get_metadata()
-    assert meta is None
+
+    with pytest.raises(
+        InvalidMetadataError, match="Missing casepath or model description"
+    ):
+        meta = myfmu.get_metadata()
 
 
 def test_fmuprovider_ert_provider_guess_casemeta_path(fmurun):
@@ -66,8 +73,11 @@ def test_fmuprovider_ert_provider_guess_casemeta_path(fmurun):
             workflow=WORKFLOW,
         )
 
-    assert myfmu.get_metadata() is None
     assert myfmu.get_casepath() is None
+    with pytest.raises(
+        InvalidMetadataError, match="Missing casepath or model description"
+    ):
+        myfmu.get_metadata()
 
 
 def test_fmuprovider_ert_provider_missing_parameter_txt(fmurun_w_casemetadata):
@@ -207,8 +217,10 @@ def test_fmuprovider_detect_no_case_metadata(fmurun):
             model=GLOBAL_CONFIG_MODEL,
             fmu_context=FmuContext.REALIZATION,
         )
-    meta = myfmu.get_metadata()
-    assert meta is None
+    with pytest.raises(
+        InvalidMetadataError, match="Missing casepath or model description"
+    ):
+        myfmu.get_metadata()
 
 
 def test_fmuprovider_case_run(fmurun_prehook):