chore: descritpion.md are now optional

Signed-off-by: ThibaultFy <[email protected]>

substra/sdk/schemas.py

@@ -2,6 +2,7 @@
 import enum
 import json
 import pathlib
+import tempfile
 import typing
 import uuid
 from typing import Dict
@@ -19,6 +20,13 @@
     "summary_task": "task",
 }
 
+GENERATED_DESCRIPTION_CONTENT = """
+# No description given
+
+To add a dataset description, create a markdown file and pass it to your
+`substra.sdk.schemasDatasetSpec` on your dataset opener registration.
+"""
+
 
 class BackendType(str, enum.Enum):
     REMOTE = "remote"
@@ -282,13 +290,24 @@ class DatasetSpec(_Spec):
 
     name: str
     data_opener: pathlib.Path  # Path to the data opener
-    description: pathlib.Path  # Path to the description file
+    description: Optional[pathlib.Path] = None  # Path to the description file
     permissions: Permissions
     metadata: Optional[Dict[str, str]] = None
     logs_permission: Permissions
 
     type_: typing.ClassVar[Type] = Type.Dataset
 
+    @pydantic.model_validator(mode="before")
+    @classmethod
+    def _check_description(cls, values):
+        if "description" not in values:
+            parent_path = pathlib.Path(values["data_opener"]).parent
+            description_path = parent_path / "generated_description.md"
+            with description_path.open("w", encoding="utf-8") as f:
+                f.write(GENERATED_DESCRIPTION_CONTENT)
+            values["description"] = description_path
+        return values
+
     class Meta:
         file_attributes = (
             "data_opener",