improve handling of unsupported types

- Introduced new explicit exception types instead of `RuntimeError`
- Introduced new `ConversionStatus` value for unsupported formats
- Tidied up converter member typing & removed asserts

Signed-off-by: Panos Vagenas <35837085+vagenas@users.noreply.github.com>

docling/datamodel/base_models.py

@@ -22,6 +22,7 @@ class ConversionStatus(str, Enum):
     FAILURE = auto()
     SUCCESS = auto()
     PARTIAL_SUCCESS = auto()
+    UNSUPPORTED = auto()
 
 
 class InputFormat(str, Enum):

docling/datamodel/document.py

@@ -3,7 +3,7 @@ import re
 from enum import Enum
 from io import BytesIO
 from pathlib import Path, PurePath
-from typing import TYPE_CHECKING, Dict, Iterable, List, Optional, Type, Union
+from typing import TYPE_CHECKING, Dict, Iterable, List, Optional, Set, Type, Union
 
 import filetype
 from docling_core.types.doc import (
@@ -164,12 +164,6 @@ class InputDocument(BaseModel):
         backend: Type[AbstractDocumentBackend],
         path_or_stream: Union[BytesIO, Path],
     ) -> None:
-        if backend is None:
-            raise RuntimeError(
-                f"No backend configuration provided for file {self.file.name} with format {self.format}. "
-                f"Please check your format configuration on DocumentConverter."
-            )
-
         self._backend = backend(self, path_or_stream=path_or_stream)
         if not self._backend.is_valid():
             self.valid = False
@@ -450,6 +444,25 @@ class ConversionResult(BaseModel):
         return ds_doc
 
 
+class _DummyBackend(AbstractDocumentBackend):
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+
+    def is_valid(self) -> bool:
+        return False
+
+    @classmethod
+    def supported_formats(cls) -> Set[InputFormat]:
+        return set()
+
+    @classmethod
+    def supports_pagination(cls) -> bool:
+        return False
+
+    def unload(self):
+        return super().unload()
+
+
 class _DocumentConversionInput(BaseModel):
 
     path_or_stream_iterator: Iterable[Union[Path, str, DocumentStream]]
@@ -461,11 +474,12 @@ class _DocumentConversionInput(BaseModel):
         for item in self.path_or_stream_iterator:
             obj = resolve_file_source(item) if isinstance(item, str) else item
             format = self._guess_format(obj)
+            backend: Type[AbstractDocumentBackend]
             if format not in format_options.keys():
-                _log.info(
+                _log.error(
-                    f"Skipping input document {obj.name} because it isn't matching any of the allowed formats."
+                    f"Input document {obj.name} does not match any allowed format."
                 )
-                continue
+                backend = _DummyBackend
             else:
                 backend = format_options[format].backend
 

docling/document_converter.py

@@ -23,6 +23,7 @@ from docling.datamodel.document import (
 )
 from docling.datamodel.pipeline_options import PipelineOptions
 from docling.datamodel.settings import DocumentLimits, settings
+from docling.exceptions import ConversionError
 from docling.pipeline.base_pipeline import BasePipeline
 from docling.pipeline.simple_pipeline import SimplePipeline
 from docling.pipeline.standard_pdf_pipeline import StandardPdfPipeline
@@ -121,18 +122,13 @@ class DocumentConverter:
         allowed_formats: Optional[List[InputFormat]] = None,
         format_options: Optional[Dict[InputFormat, FormatOption]] = None,
     ):
-        self.allowed_formats = allowed_formats
+        self.allowed_formats = (
-        self.format_to_options = format_options
+            allowed_formats if allowed_formats is not None else [e for e in InputFormat]
-
+        )
-        if self.allowed_formats is None:
+        self.format_to_options = (
-            # if self.format_to_options is not None:
+            format_options if format_options is not None else _format_to_default_options
-            #    self.allowed_formats = self.format_to_options.keys()
+        )
-            # else:
+        if format_options is not None:
-            self.allowed_formats = [e for e in InputFormat]  # all formats
-
-        if self.format_to_options is None:
-            self.format_to_options = _format_to_default_options
-        else:
             for f in self.allowed_formats:
                 if f not in self.format_to_options.keys():
                     _log.debug(f"Requested format {f} will use default options.")
@@ -150,7 +146,11 @@ class DocumentConverter:
 
     def initialize_pipeline(self, format: InputFormat):
         """Initialize the conversion pipeline for the selected format."""
-        self._get_pipeline(doc_format=format)
+        pipeline = self._get_pipeline(doc_format=format)
+        if pipeline is None:
+            raise ConversionError(
+                f"No pipeline could be initialized for format {format}"
+            )
 
     @validate_call(config=ConfigDict(strict=True))
     def convert(
@@ -159,7 +159,7 @@ class DocumentConverter:
         raises_on_error: bool = True,
         max_num_pages: int = sys.maxsize,
         max_file_size: int = sys.maxsize,
-    ) -> Optional[ConversionResult]:
+    ) -> ConversionResult:
 
         all_res = self.convert_all(
             source=[source],
@@ -167,7 +167,7 @@ class DocumentConverter:
             max_num_pages=max_num_pages,
             max_file_size=max_file_size,
         )
-        return next(all_res, None)
+        return next(all_res)
 
     @validate_call(config=ConfigDict(strict=True))
     def convert_all(
@@ -194,22 +194,20 @@ class DocumentConverter:
                 ConversionStatus.SUCCESS,
                 ConversionStatus.PARTIAL_SUCCESS,
             }:
-                raise RuntimeError(
+                raise ConversionError(
                     f"Conversion failed for: {conv_res.input.file} with status: {conv_res.status}"
                 )
             else:
                 yield conv_res
 
         if not had_result and raises_on_error:
-            raise RuntimeError(
+            raise ConversionError(
                 f"Conversion failed because the provided file has no recognizable format or it wasn't in the list of allowed formats."
             )
 
     def _convert(
         self, conv_input: _DocumentConversionInput, raises_on_error: bool
     ) -> Iterator[ConversionResult]:
-        assert self.format_to_options is not None
-
         start_time = time.monotonic()
 
         for input_batch in chunkify(
@@ -231,27 +229,22 @@ class DocumentConverter:
             ):
                 elapsed = time.monotonic() - start_time
                 start_time = time.monotonic()
-
-                if item is not None:
                 _log.info(
                     f"Finished converting document {item.input.file.name} in {elapsed:.2f} sec."
                 )
                 yield item
-                else:
-                    _log.info(f"Skipped a document. We lost {elapsed:.2f} sec.")
 
     def _get_pipeline(self, doc_format: InputFormat) -> Optional[BasePipeline]:
-        assert self.format_to_options is not None
-
         fopt = self.format_to_options.get(doc_format)
 
         if fopt is None:
-            raise RuntimeError(f"Could not get pipeline for {doc_format}")
+            return None
         else:
             pipeline_class = fopt.pipeline_cls
             pipeline_options = fopt.pipeline_options
 
-        assert pipeline_options is not None
+        if pipeline_options is None:
+            return None
         # TODO this will ignore if different options have been defined for the same pipeline class.
         if (
             pipeline_class not in self.initialized_pipelines
@@ -265,11 +258,20 @@ class DocumentConverter:
 
     def _process_document(
         self, in_doc: InputDocument, raises_on_error: bool
-    ) -> Optional[ConversionResult]:
+    ) -> ConversionResult:
-        assert self.allowed_formats is not None
-        assert in_doc.format in self.allowed_formats
 
+        valid = (
+            self.allowed_formats is not None and in_doc.format in self.allowed_formats
+        )
+        if valid:
             conv_res = self._execute_pipeline(in_doc, raises_on_error=raises_on_error)
+        else:
+            if raises_on_error:
+                raise ConversionError(f"Unsupported format in: {in_doc.file}")
+            else:
+                conv_res = ConversionResult(
+                    input=in_doc, status=ConversionStatus.UNSUPPORTED
+                )
 
         return conv_res
 
@@ -278,26 +280,28 @@ class DocumentConverter:
     ) -> ConversionResult:
         if in_doc.valid:
             pipeline = self._get_pipeline(in_doc.format)
-            if pipeline is None:  # Can't find a default pipeline. Should this raise?
+            if pipeline is not None:
+                conv_res = pipeline.execute(in_doc, raises_on_error=raises_on_error)
+            else:
                 if raises_on_error:
-                    raise RuntimeError(
+                    raise ConversionError(
                         f"No pipeline could be initialized for {in_doc.file}."
                     )
                 else:
-                    conv_res = ConversionResult(input=in_doc)
+                    conv_res = ConversionResult(
-                    conv_res.status = ConversionStatus.FAILURE
+                        input=in_doc,
-                    return conv_res
+                        status=ConversionStatus.FAILURE,
-
+                    )
-            conv_res = pipeline.execute(in_doc, raises_on_error=raises_on_error)
-
         else:
             if raises_on_error:
-                raise RuntimeError(f"Input document {in_doc.file} is not valid.")
+                raise ConversionError(f"Input document {in_doc.file} is not valid.")
 
             else:
                 # invalid doc or not of desired format
-                conv_res = ConversionResult(input=in_doc)
+                conv_res = ConversionResult(
-                conv_res.status = ConversionStatus.FAILURE
+                    input=in_doc,
+                    status=ConversionStatus.FAILURE,
+                )
                 # TODO add error log why it failed.
 
         return conv_res

docling/exceptions.py

@@ -0,0 +1,6 @@
+class BaseError(RuntimeError):
+    pass
+
+
+class ConversionError(BaseError):
+    pass

tests/test_invalid_input.py

@@ -4,7 +4,7 @@ from pathlib import Path
 import pytest
 
 from docling.datamodel.base_models import ConversionStatus, DocumentStream
-from docling.document_converter import DocumentConverter
+from docling.document_converter import ConversionError, DocumentConverter
 
 
 def get_pdf_path():
@@ -20,26 +20,26 @@ def converter():
     return converter
 
 
-def test_convert_invalid_doc(converter: DocumentConverter):
+def test_convert_unsupported_doc_format_wout_exception(converter: DocumentConverter):
-
-    # Test with unrecognizable file format (xyz)
     result = converter.convert(
         DocumentStream(name="input.xyz", stream=BytesIO(b"xyz")), raises_on_error=False
     )
-    assert result is None  # No result comes back at all, since this file is skipped.
+    assert result.status == ConversionStatus.UNSUPPORTED
 
-    with pytest.raises(RuntimeError):
+
-        result = converter.convert(
+def test_convert_unsupported_doc_format_with_exception(converter: DocumentConverter):
+    with pytest.raises(ConversionError):
+        converter.convert(
             DocumentStream(name="input.xyz", stream=BytesIO(b"xyz")),
             raises_on_error=True,
         )
 
-    # Test with too small filesize limit
+
+def test_convert_too_small_filesize_limit_wout_exception(converter: DocumentConverter):
     result = converter.convert(get_pdf_path(), max_file_size=1, raises_on_error=False)
-    assert result is not None
     assert result.status == ConversionStatus.FAILURE
 
-    with pytest.raises(RuntimeError):
+
-        result = converter.convert(
+def test_convert_too_small_filesize_limit_with_exception(converter: DocumentConverter):
-            get_pdf_path(), max_file_size=1, raises_on_error=True
+    with pytest.raises(ConversionError):
-        )
+        converter.convert(get_pdf_path(), max_file_size=1, raises_on_error=True)