Fix mypy and add recursive tranformation

airbyte_cdk/sources/declarative/declarative_component_schema.yaml

@@ -1234,7 +1234,7 @@ definitions:
             - "$ref": "#/definitions/CustomTransformation"
             - "$ref": "#/definitions/RemoveFields"
             - "$ref": "#/definitions/KeysToLower"
-            - "$ref": "#/definitions/KeyToSnakeCase"
+            - "$ref": "#/definitions/KeysToSnakeCase"
       state_migrations:
         title: State Migrations
         description: Array of state migrations to be applied on the input state
@@ -1839,7 +1839,7 @@ definitions:
       $parameters:
         type: object
         additionalProperties: true
-  KeyToSnakeCase:
+  KeysToSnakeCase:
     title: Key to Snake Case
     description: A transformation that renames all keys to snake case.
     type: object
@@ -1848,7 +1848,7 @@ definitions:
     properties:
       type:
         type: string
-        enum: [KeyToSnakeCase]
+        enum: [KeysToSnakeCase]
       $parameters:
         type: object
         additionalProperties: true

airbyte_cdk/sources/declarative/models/declarative_component_schema.py

@@ -710,8 +710,8 @@ class KeysToLower(BaseModel):
     parameters: Optional[Dict[str, Any]] = Field(None, alias="$parameters")
 
 
-class KeyToSnakeCase(BaseModel):
-    type: Literal["KeyToSnakeCase"]
+class KeysToSnakeCase(BaseModel):
+    type: Literal["KeysToSnakeCase"]
     parameters: Optional[Dict[str, Any]] = Field(None, alias="$parameters")
 
 
@@ -1665,7 +1665,7 @@ class Config:
                 CustomTransformation,
                 RemoveFields,
                 KeysToLower,
-                KeyToSnakeCase,
+                KeysToSnakeCase,
             ]
         ]
     ] = Field(

airbyte_cdk/sources/declarative/transformations/keys_to_snake_transformation.py

@@ -4,20 +4,19 @@
 
 import re
 from dataclasses import dataclass
-from typing import Any, Dict, Optional
+from typing import Any, Dict, List, Optional
 
 import unidecode
 
 from airbyte_cdk.sources.declarative.transformations import RecordTransformation
 from airbyte_cdk.sources.types import Config, StreamSlice, StreamState
 
-TOKEN_PATTERN = re.compile(r"[A-Z]+[a-z]*|[a-z]+|\d+|(?P<NoToken>[^a-zA-Z\d]+)")
-DEFAULT_SEPARATOR = "_"
-
 
 @dataclass
-class KeyToSnakeCaseTransformation(RecordTransformation):
-    token_pattern: re.Pattern = TOKEN_PATTERN
+class KeysToSnakeCaseTransformation(RecordTransformation):
+    token_pattern: re.Pattern[str] = re.compile(
+        r"[A-Z]+[a-z]*|[a-z]+|\d+|(?P<NoToken>[^a-zA-Z\d]+)"
+    )
 
     def transform(
         self,
@@ -26,13 +25,22 @@ def transform(
         stream_state: Optional[StreamState] = None,
         stream_slice: Optional[StreamSlice] = None,
     ) -> None:
-        transformed_record = {}
-        for key in record:
-            transformed_key = self.process_key(key)
-            transformed_record[transformed_key] = record[key]
+        transformed_record = self._transform_record(record)
         record.clear()
         record.update(transformed_record)
 
+    def _transform_record(self, record: Dict[str, Any]) -> Dict[str, Any]:
+        transformed_record = {}
+        for key, value in record.items():
+            transformed_key = self.process_key(key)
+            transformed_value = value
+
+            if isinstance(value, dict):
+                transformed_value = self._transform_record(value)
+
+            transformed_record[transformed_key] = transformed_value
+        return transformed_record
+
     def process_key(self, key: str) -> str:
         key = self.normalize_key(key)
         tokens = self.tokenize_key(key)
@@ -42,19 +50,19 @@ def process_key(self, key: str) -> str:
     def normalize_key(self, key: str) -> str:
         return unidecode.unidecode(key)
 
-    def tokenize_key(self, key: str) -> list:
+    def tokenize_key(self, key: str) -> List[str]:
         tokens = []
         for match in self.token_pattern.finditer(key):
             token = match.group(0) if match.group("NoToken") is None else ""
             tokens.append(token)
         return tokens
 
-    def filter_tokens(self, tokens: list) -> list:
+    def filter_tokens(self, tokens: List[str]) -> List[str]:
         if len(tokens) >= 3:
             tokens = tokens[:1] + [t for t in tokens[1:-1] if t] + tokens[-1:]
         if tokens and tokens[0].isdigit():
             tokens.insert(0, "")
         return tokens
 
-    def tokens_to_snake_case(self, tokens: list) -> str:
+    def tokens_to_snake_case(self, tokens: List[str]) -> str:
         return "_".join(token.lower() for token in tokens)

unit_tests/sources/declarative/transformations/test_keys_to_snake_transformation.py

@@ -5,7 +5,7 @@
 import pytest
 
 from airbyte_cdk.sources.declarative.transformations.keys_to_snake_transformation import (
-    KeyToSnakeCaseTransformation,
+    KeysToSnakeCaseTransformation,
 )
 
 _ANY_VALUE = -1
@@ -22,6 +22,16 @@
             {"123Number": _ANY_VALUE, "456Another123": _ANY_VALUE},
             {"_123_number": _ANY_VALUE, "_456_another_123": _ANY_VALUE},
         ),
+        (
+            {
+                "NestedRecord": {"FirstName": _ANY_VALUE, "lastName": _ANY_VALUE},
+                "456Another123": _ANY_VALUE,
+            },
+            {
+                "nested_record": {"first_name": _ANY_VALUE, "last_name": _ANY_VALUE},
+                "_456_another_123": _ANY_VALUE,
+            },
+        ),
         (
             {"hello@world": _ANY_VALUE, "test#case": _ANY_VALUE},
             {"hello_world": _ANY_VALUE, "test_case": _ANY_VALUE},
@@ -43,6 +53,6 @@
         ),
     ],
 )
-def test_key_transformation(input_keys, expected_keys):
-    KeyToSnakeCaseTransformation().transform(input_keys)
+def test_keys_transformation(input_keys, expected_keys):
+    KeysToSnakeCaseTransformation().transform(input_keys)
     assert input_keys == expected_keys