feat(low-code cdk): add flatten fields (#181)

airbyte_cdk/sources/declarative/declarative_component_schema.yaml

@@ -1852,6 +1852,19 @@ definitions:
       $parameters:
         type: object
         additionalProperties: true
+  FlattenFields:
+    title: Flatten Fields
+    description: A transformation that flatten record to single level format.
+    type: object
+    required:
+      - type
+    properties:
+      type:
+        type: string
+        enum: [FlattenFields]
+      $parameters:
+        type: object
+        additionalProperties: true
   IterableDecoder:
     title: Iterable Decoder
     description: Use this if the response consists of strings separated by new lines (`\n`). The Decoder will wrap each row into a JSON object with the `record` key.

airbyte_cdk/sources/declarative/models/declarative_component_schema.py

@@ -715,6 +715,11 @@ class KeysToSnakeCase(BaseModel):
     parameters: Optional[Dict[str, Any]] = Field(None, alias="$parameters")
 
 
+class FlattenFields(BaseModel):
+    type: Literal["FlattenFields"]
+    parameters: Optional[Dict[str, Any]] = Field(None, alias="$parameters")
+
+
 class IterableDecoder(BaseModel):
     type: Literal["IterableDecoder"]
 

airbyte_cdk/sources/declarative/parsers/model_to_component_factory.py

@@ -197,6 +197,9 @@
 from airbyte_cdk.sources.declarative.models.declarative_component_schema import (
     ExponentialBackoffStrategy as ExponentialBackoffStrategyModel,
 )
+from airbyte_cdk.sources.declarative.models.declarative_component_schema import (
+    FlattenFields as FlattenFieldsModel,
+)
 from airbyte_cdk.sources.declarative.models.declarative_component_schema import (
     GzipJsonDecoder as GzipJsonDecoderModel,
 )
@@ -387,6 +390,9 @@
     RemoveFields,
 )
 from airbyte_cdk.sources.declarative.transformations.add_fields import AddedFieldDefinition
+from airbyte_cdk.sources.declarative.transformations.flatten_fields import (
+    FlattenFields,
+)
 from airbyte_cdk.sources.declarative.transformations.keys_to_lower_transformation import (
     KeysToLowerTransformation,
 )
@@ -472,6 +478,7 @@ def _init_mappings(self) -> None:
             JsonlDecoderModel: self.create_jsonl_decoder,
             GzipJsonDecoderModel: self.create_gzipjson_decoder,
             KeysToLowerModel: self.create_keys_to_lower_transformation,
+            FlattenFieldsModel: self.create_flatten_fields,
             IterableDecoderModel: self.create_iterable_decoder,
             XmlDecoderModel: self.create_xml_decoder,
             JsonFileSchemaLoaderModel: self.create_json_file_schema_loader,
@@ -587,6 +594,11 @@ def create_keys_to_lower_transformation(
     ) -> KeysToLowerTransformation:
         return KeysToLowerTransformation()
 
+    def create_flatten_fields(
+        self, model: FlattenFieldsModel, config: Config, **kwargs: Any
+    ) -> FlattenFields:
+        return FlattenFields()
+
     @staticmethod
     def _json_schema_type_name_to_type(value_type: Optional[ValueType]) -> Optional[Type[Any]]:
         if not value_type:

airbyte_cdk/sources/declarative/transformations/flatten_fields.py

@@ -0,0 +1,50 @@
+#
+# Copyright (c) 2024 Airbyte, Inc., all rights reserved.
+#
+
+from dataclasses import dataclass
+from typing import Any, Dict, Optional
+
+from airbyte_cdk.sources.declarative.transformations import RecordTransformation
+from airbyte_cdk.sources.types import Config, StreamSlice, StreamState
+
+
+@dataclass
+class FlattenFields(RecordTransformation):
+    def transform(
+        self,
+        record: Dict[str, Any],
+        config: Optional[Config] = None,
+        stream_state: Optional[StreamState] = None,
+        stream_slice: Optional[StreamSlice] = None,
+    ) -> None:
+        transformed_record = self.flatten_record(record)
+        record.clear()
+        record.update(transformed_record)
+
+    def flatten_record(self, record: Dict[str, Any]) -> Dict[str, Any]:
+        stack = [(record, "_")]
+        transformed_record: Dict[str, Any] = {}
+        force_with_parent_name = False
+
+        while stack:
+            current_record, parent_key = stack.pop()
+
+            if isinstance(current_record, dict):
+                for current_key, value in current_record.items():
+                    new_key = (
+                        f"{parent_key}.{current_key}"
+                        if (current_key in transformed_record or force_with_parent_name)
+                        else current_key
+                    )
+                    stack.append((value, new_key))
+
+            elif isinstance(current_record, list):
+                for i, item in enumerate(current_record):
+                    force_with_parent_name = True
+                    stack.append((item, f"{parent_key}.{i}"))
+
+            else:
+                transformed_record[parent_key] = current_record
+
+        return transformed_record

unit_tests/sources/declarative/transformations/test_flatten_fields.py

@@ -0,0 +1,54 @@
+#
+# Copyright (c) 2024 Airbyte, Inc., all rights reserved.
+#
+
+import pytest
+
+from airbyte_cdk.sources.declarative.transformations.flatten_fields import (
+    FlattenFields,
+)
+
+
+@pytest.mark.parametrize(
+    "input_record, expected_output",
+    [
+        ({"FirstName": "John", "LastName": "Doe"}, {"FirstName": "John", "LastName": "Doe"}),
+        ({"123Number": 123, "456Another123": 456}, {"123Number": 123, "456Another123": 456}),
+        (
+            {
+                "NestedRecord": {"FirstName": "John", "LastName": "Doe"},
+                "456Another123": 456,
+            },
+            {
+                "FirstName": "John",
+                "LastName": "Doe",
+                "456Another123": 456,
+            },
+        ),
+        (
+            {"ListExample": [{"A": "a"}, {"A": "b"}]},
+            {"ListExample.0.A": "a", "ListExample.1.A": "b"},
+        ),
+        (
+            {
+                "MixedCase123": {
+                    "Nested": [{"Key": {"Value": "test1"}}, {"Key": {"Value": "test2"}}]
+                },
+                "SimpleKey": "SimpleValue",
+            },
+            {
+                "Nested.0.Key.Value": "test1",
+                "Nested.1.Key.Value": "test2",
+                "SimpleKey": "SimpleValue",
+            },
+        ),
+        (
+            {"List": ["Item1", "Item2", "Item3"]},
+            {"List.0": "Item1", "List.1": "Item2", "List.2": "Item3"},
+        ),
+    ],
+)
+def test_flatten_fields(input_record, expected_output):
+    flattener = FlattenFields()
+    flattener.transform(input_record)
+    assert input_record == expected_output