Lazy data files resolution and offline cache reload

src/datasets/builder.py

@@ -46,12 +46,12 @@
     ReadInstruction,
 )
 from .arrow_writer import ArrowWriter, BeamWriter, ParquetWriter, SchemaInferenceError
-from .data_files import DataFilesDict, sanitize_patterns
+from .data_files import DataFilesDict, DataFilesPatternsDict, sanitize_patterns
 from .dataset_dict import DatasetDict, IterableDatasetDict
 from .download.download_config import DownloadConfig
 from .download.download_manager import DownloadManager, DownloadMode
 from .download.mock_download_manager import MockDownloadManager
-from .download.streaming_download_manager import StreamingDownloadManager, xopen
+from .download.streaming_download_manager import StreamingDownloadManager, xjoin, xopen
 from .features import Features
 from .filesystems import (
     is_remote_filesystem,
@@ -128,7 +128,7 @@ class BuilderConfig:
     name: str = "default"
     version: Optional[Union[utils.Version, str]] = utils.Version("0.0.0")
     data_dir: Optional[str] = None
-    data_files: Optional[DataFilesDict] = None
+    data_files: Optional[Union[DataFilesDict, DataFilesPatternsDict]] = None
     description: Optional[str] = None
 
     def __post_init__(self):
@@ -139,7 +139,7 @@ def __post_init__(self):
                     f"Bad characters from black list '{INVALID_WINDOWS_CHARACTERS_IN_PATH}' found in '{self.name}'. "
                     f"They could create issues when creating a directory for this config on Windows filesystem."
                 )
-        if self.data_files is not None and not isinstance(self.data_files, DataFilesDict):
+        if self.data_files is not None and not isinstance(self.data_files, (DataFilesDict, DataFilesPatternsDict)):
             raise ValueError(f"Expected a DataFilesDict in data_files but got {self.data_files}")
 
     def __eq__(self, o):
@@ -213,6 +213,11 @@ def create_config_id(
         else:
             return self.name
 
+    def _resolve_data_files(self, base_path: str, download_config: DownloadConfig) -> None:
+        if isinstance(self.data_files, DataFilesPatternsDict):
+            base_path = xjoin(base_path, self.data_dir) if self.data_dir else base_path
+            self.data_files = self.data_files.resolve(base_path, download_config)
+
 
 class DatasetBuilder:
     """Abstract base class for all datasets.
@@ -517,7 +522,7 @@ def _create_builder_config(
         builder_config = None
 
         # try default config
-        if config_name is None and self.BUILDER_CONFIGS and not config_kwargs:
+        if config_name is None and self.BUILDER_CONFIGS:
             if self.DEFAULT_CONFIG_NAME is not None:
                 builder_config = self.builder_configs.get(self.DEFAULT_CONFIG_NAME)
                 logger.info(f"No config specified, defaulting to: {self.dataset_name}/{builder_config.name}")
@@ -555,7 +560,7 @@ def _create_builder_config(
 
         # otherwise use the config_kwargs to overwrite the attributes
         else:
-            builder_config = copy.deepcopy(builder_config)
+            builder_config = copy.deepcopy(builder_config) if config_kwargs else builder_config
             for key, value in config_kwargs.items():
                 if value is not None:
                     if not hasattr(builder_config, key):
@@ -565,6 +570,12 @@ def _create_builder_config(
         if not builder_config.name:
             raise ValueError(f"BuilderConfig must have a name, got {builder_config.name}")
 
+        # resolve data files if needed
+        builder_config._resolve_data_files(
+            base_path=self.base_path,
+            download_config=DownloadConfig(token=self.token, storage_options=self.storage_options),
+        )
+
         # compute the config id that is going to be used for caching
         config_id = builder_config.create_config_id(
             config_kwargs,
@@ -590,7 +601,7 @@ def _create_builder_config(
     @classproperty
     @classmethod
     @memoize()
-    def builder_configs(cls):
+    def builder_configs(cls) -> Dict[str, BuilderConfig]:
         """Dictionary of pre-defined configurations for this builder class."""
         configs = {config.name: config for config in cls.BUILDER_CONFIGS}
         if len(configs) != len(cls.BUILDER_CONFIGS):

src/datasets/data_files.py

@@ -698,3 +698,94 @@ def filter_extensions(self, extensions: List[str]) -> "DataFilesDict":
         for key, data_files_list in self.items():
             out[key] = data_files_list.filter_extensions(extensions)
         return out
+
+
+class DataFilesPatternsList(List[str]):
+    """
+    List of data files patterns (absolute local paths or URLs).
+    For each pattern there should also be a list of allowed extensions
+    to keep, or a None ot keep all the files for the pattern.
+    """
+
+    def __init__(
+        self,
+        patterns: List[str],
+        allowed_extensions: List[Optional[List[str]]],
+    ):
+        super().__init__(patterns)
+        self.allowed_extensions = allowed_extensions
+
+    def __add__(self, other):
+        return DataFilesList([*self, *other], self.allowed_extensions + other.allowed_extensions)
+
+    @classmethod
+    def from_patterns(
+        cls, patterns: List[str], allowed_extensions: Optional[List[str]] = None
+    ) -> "DataFilesPatternsDict":
+        return cls(patterns, [allowed_extensions] * len(patterns))
+
+    def resolve(
+        self,
+        base_path: str,
+        download_config: Optional[DownloadConfig] = None,
+    ) -> "DataFilesList":
+        base_path = base_path if base_path is not None else Path().resolve().as_posix()
+        data_files = []
+        for pattern, allowed_extensions in zip(self, self.allowed_extensions):
+            try:
+                data_files.extend(
+                    resolve_pattern(
+                        pattern,
+                        base_path=base_path,
+                        allowed_extensions=allowed_extensions,
+                        download_config=download_config,
+                    )
+                )
+            except FileNotFoundError:
+                if not has_magic(pattern):
+                    raise
+        origin_metadata = _get_origin_metadata(data_files, download_config=download_config)
+        return DataFilesList(data_files, origin_metadata)
+
+    def filter_extensions(self, extensions: List[str]) -> "DataFilesList":
+        return DataFilesPatternsList(
+            self, [allowed_extensions + extensions for allowed_extensions in self.allowed_extensions]
+        )
+
+
+class DataFilesPatternsDict(Dict[str, DataFilesPatternsList]):
+    """
+    Dict of split_name -> list of data files patterns (absolute local paths or URLs).
+    """
+
+    @classmethod
+    def from_patterns(
+        cls, patterns: Dict[str, List[str]], allowed_extensions: Optional[List[str]] = None
+    ) -> "DataFilesPatternsDict":
+        out = cls()
+        for key, patterns_for_key in patterns.items():
+            out[key] = (
+                DataFilesPatternsList.from_patterns(
+                    patterns_for_key,
+                    allowed_extensions=allowed_extensions,
+                )
+                if not isinstance(patterns_for_key, DataFilesPatternsList)
+                else patterns_for_key
+            )
+        return out
+
+    def resolve(
+        self,
+        base_path: str,
+        download_config: Optional[DownloadConfig] = None,
+    ) -> "DataFilesDict":
+        out = DataFilesDict()
+        for key, data_files_patterns_list in self.items():
+            out[key] = data_files_patterns_list.resolve(base_path, download_config)
+        return out
+
+    def filter_extensions(self, extensions: List[str]) -> "DataFilesPatternsDict":
+        out = type(self)()
+        for key, data_files_patterns_list in self.items():
+            out[key] = data_files_patterns_list.filter_extensions(extensions)
+        return out