feat: allow to set an orjson default (#64)

src/py_avro_schema/__init__.py

@@ -23,7 +23,7 @@
 """
 
 import importlib.metadata
-from typing import Optional, Type
+from typing import Any, Callable, Optional, Type, Union
 
 import memoization
 import orjson
@@ -50,6 +50,7 @@ def generate(
     *,
     namespace: Optional[str] = None,
     options: Option = Option(0),
+    orjson_default: Union[Callable[[Any], Any], None] = None,
 ) -> bytes:
     """
     Return an Avro schema as a JSON-formatted bytestring for a given Python class or instance
@@ -60,11 +61,12 @@ def generate(
     :param namespace: The Avro namespace to add to schemas.
     :param options:   Schema generation options as defined by :class:`Option` enum values. Specify multiple values like
                       this: ``Option.INT_32 | Option.FLOAT_32``.
+    :param orjson_default: A function to serialize custom types with orjson.
     """
     schema_dict = schema(py_type, namespace=namespace, options=options)
     json_options = 0
     for opt in JSON_OPTIONS:
         if opt in options:
             json_options |= opt.value
-    schema_json = orjson.dumps(schema_dict, option=json_options)
+    schema_json = orjson.dumps(schema_dict, option=json_options, default=orjson_default)
     return schema_json

tests/test_avro_schema.py

@@ -10,9 +10,11 @@
 # specific language governing permissions and limitations under the License.
 
 import dataclasses
+from typing import Any
 
 import avro.schema
 import orjson
+import pydantic
 
 import py_avro_schema as pas
 
@@ -43,3 +45,43 @@ class PyType:
     json_data = pas.generate(PyType)
     assert json_data == orjson.dumps(expected)
     assert avro.schema.parse(json_data)
+
+
+def test_pydantic_field_default():
+    class Default(pydantic.BaseModel):
+        """My Default"""
+
+        foo: str = "foo"
+
+    class PyType(pydantic.BaseModel):
+        """My PyType"""
+
+        default: Default = pydantic.Field(default_factory=Default)
+
+    def pydantic_serializer(value: Any) -> dict:
+        if isinstance(value, pydantic.BaseModel):
+            return value.model_dump(mode="json")
+        raise TypeError
+
+    expected = {
+        "type": "record",
+        "name": "PyType",
+        "fields": [
+            {
+                "name": "default",
+                "type": {
+                    "type": "record",
+                    "name": "Default",
+                    "fields": [{"name": "foo", "type": "string", "default": "foo"}],
+                    "namespace": "test_avro_schema",
+                    "doc": "My Default",
+                },
+                "default": {"foo": "foo"},
+            }
+        ],
+        "namespace": "test_avro_schema",
+        "doc": "My PyType",
+    }
+    json_data = pas.generate(PyType, orjson_default=pydantic_serializer)
+    assert json_data == orjson.dumps(expected)
+    assert avro.schema.parse(json_data)