allow empty maps instead of null

CHANGELOG.md

@@ -1,5 +1,11 @@
 # Qenerate Changelog
 
+## 0.7.0
+
+New Features:
+
+* Add `empty_map_to_none` to properly handle `{}` responses ([#76](https://github.com/app-sre/qenerate/pull/76))
+
 ## 0.6.1
 
 BUGFIX:

README.md

@@ -114,6 +114,17 @@ The above will tell qenerate to map the GQL `JSON` type to `str` instead of pyda
 # qenerate: map_gql_scalar=DateTime -> str
 ```
 
+### Allow Empty Maps
+
+Some GQL servers might return an empty map `{}` instead of `null`. In that case you can use `empty_map_to_none=True`.
+This will properly convert `{}` to `None`. By default this behavior is disabled, because it adds some
+extra overhead when converting untyped data to typed classes. E.g., in case of `pydantic_v1` we add
+a `@root_validator` to iterate over each given value. 
+
+```graphql
+# qenerate: empty_map_to_none=True
+```
+
 ### Naming Collision Strategy
 
 ```graphql

pyproject.toml

@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "qenerate"
-version = "0.6.1"
+version = "0.7.0"
 description = "Code Generator for GraphQL Query and Fragment Data Classes"
 authors = [
     "Red Hat - Service Delivery - AppSRE <[email protected]>"

qenerate/core/feature_flag_parser.py

@@ -14,6 +14,7 @@ class FeatureFlags:
     plugin: str
     gql_scalar_mappings: Mapping[str, str]
     collision_strategy: NamingCollisionStrategy = NamingCollisionStrategy.PARENT_CONTEXT
+    empty_map_to_none: bool = False
 
 
 class FeatureFlagError(Exception):
@@ -56,6 +57,17 @@ def custom_type_mapping(definition: str) -> dict[str, str]:
         for groups in m:
             mappings[groups[0]] = groups[1]
         return mappings
+
+    @staticmethod
+    def empty_map_to_none(definition: str) -> bool:
+        m = re.search(
+            r"#\s*qenerate:\s*empty_map_to_none\s*=\s*(\w+)\s*",
+            definition,
+        )
+        allow = False
+        if m:
+            allow = m.group(1) in ("True", "true", "TRUE", "yes")
+        return allow
 
     @staticmethod
     def parse(definition: str) -> FeatureFlags:
@@ -67,4 +79,7 @@ def parse(definition: str) -> FeatureFlags:
             gql_scalar_mappings=FeatureFlagParser.custom_type_mapping(
                 definition=definition
             ),
+            empty_map_to_none=FeatureFlagParser.empty_map_to_none(
+                definition=definition
+            )
         )

qenerate/plugins/pydantic_v1/plugin.py

@@ -76,6 +76,25 @@
 )
 
 
+CONF_WITH_VALIDATOR = (
+    f"class {BASE_CLASS_NAME}(BaseModel):\n"
+    f"{INDENT}@root_validator(pre=True)\n"
+    f"{INDENT}def remove_empty(cls, values: dict):\n"
+    f"{INDENT}{INDENT}fields = list(values.keys())\n"
+    f"{INDENT}{INDENT}for field in fields:\n"
+    f"{INDENT}{INDENT}{INDENT}value = values[field]\n"
+    f"{INDENT}{INDENT}{INDENT}if isinstance(value, dict):\n"
+    f"{INDENT}{INDENT}{INDENT}{INDENT}if not values[field]:\n"
+    f"{INDENT}{INDENT}{INDENT}{INDENT}{INDENT}values[field] = None\n"
+    f"{INDENT}{INDENT}return values\n\n"
+    f"{INDENT}class Config:\n"
+    # https://pydantic-docs.helpmanual.io/usage/model_config/#smart-union
+    # https://stackoverflow.com/a/69705356/4478420
+    f"{INDENT}{INDENT}smart_union=True\n"
+    f"{INDENT}{INDENT}extra=Extra.forbid"
+)
+
+
 def query_convenience_function(cls: str) -> str:
     return f"""
 def query(query_func: Callable, **kwargs: Any) -> {cls}:
@@ -374,7 +393,10 @@ def generate_fragments(
                 if fragment_imports:
                     result += "\n"
                     result += fragment_imports
-                result += f"\n\n\n{CONF}"
+                if definition.feature_flags.empty_map_to_none:
+                    result += f"\n\n\n{CONF_WITH_VALIDATOR}"
+                else:
+                    result += f"\n\n\n{CONF}"
                 qf = definition.source_file
                 parser = QueryParser()
                 ast = parser.parse(
@@ -469,7 +491,10 @@ def generate_operations(
                 )
             )
             result += 'DEFINITION = """\n' f"{assembled_definition}" '\n"""'
-            result += f"\n\n\n{CONF}"
+            if definition.feature_flags.empty_map_to_none:
+                result += f"\n\n\n{CONF_WITH_VALIDATOR}"
+            else:
+                result += f"\n\n\n{CONF}"
             parser = QueryParser()
             ast = parser.parse(
                 definition=definition,

setup.py

@@ -16,7 +16,7 @@
 
 setup_kwargs = {
     "name": "qenerate",
-    "version": "0.6.1",
+    "version": "0.7.0",
     "description": "Code Generator for GraphQL Query and Fragment Data Classes",
     "long_description": "Qenerate is a Code Generator for GraphQL Query and Fragment Data Classes. Documentation is at https://github.com/app-sre/qenerate .",
     "author": "Service Delivery - AppSRE",

tests/core/test_feature_flags.py

@@ -19,6 +19,7 @@
                 plugin="PluginV1",
                 collision_strategy=NamingCollisionStrategy.PARENT_CONTEXT,
                 gql_scalar_mappings={},
+                empty_map_to_none=False,
             ),
         ],
         [
@@ -31,6 +32,7 @@
                 plugin="PluginV1",
                 collision_strategy=NamingCollisionStrategy.ENUMERATE,
                 gql_scalar_mappings={},
+                empty_map_to_none=False,
             ),
         ],
         [
@@ -43,6 +45,7 @@
                 plugin="PluginV1",
                 collision_strategy=NamingCollisionStrategy.PARENT_CONTEXT,
                 gql_scalar_mappings={},
+                empty_map_to_none=False,
             ),
         ],
         [
@@ -55,6 +58,7 @@
                 plugin="PluginV1",
                 collision_strategy=NamingCollisionStrategy.PARENT_CONTEXT,
                 gql_scalar_mappings={"JSON": "str"},
+                empty_map_to_none=False,
             ),
         ],
         [
@@ -68,6 +72,46 @@
                 plugin="PluginV1",
                 collision_strategy=NamingCollisionStrategy.PARENT_CONTEXT,
                 gql_scalar_mappings={"JSON": "str", "A": "B"},
+                empty_map_to_none=False,
+            ),
+        ],
+        [
+            """
+            # qenerate: plugin=PluginV1
+            # qenerate: empty_map_to_none=True
+            query {}
+            """,
+            FeatureFlags(
+                plugin="PluginV1",
+                collision_strategy=NamingCollisionStrategy.PARENT_CONTEXT,
+                gql_scalar_mappings={},
+                empty_map_to_none=True,
+            ),
+        ],
+        [
+            """
+            # qenerate: plugin=PluginV1
+            # qenerate: empty_map_to_none=true
+            query {}
+            """,
+            FeatureFlags(
+                plugin="PluginV1",
+                collision_strategy=NamingCollisionStrategy.PARENT_CONTEXT,
+                gql_scalar_mappings={},
+                empty_map_to_none=True,
+            ),
+        ],
+        [
+            """
+            # qenerate: plugin=PluginV1
+            # qenerate: empty_map_to_none=no
+            query {}
+            """,
+            FeatureFlags(
+                plugin="PluginV1",
+                collision_strategy=NamingCollisionStrategy.PARENT_CONTEXT,
+                gql_scalar_mappings={},
+                empty_map_to_none=False,
             ),
         ],
     ],

tests/generator/definitions/empty_map_to_none/fragment.gql

@@ -0,0 +1,6 @@
+fragment VaultSecret on VaultSecret_v1 {
+    path
+    field
+    version
+    format
+}

tests/generator/definitions/empty_map_to_none/query.gql

@@ -0,0 +1,9 @@
+query SaasFilesWithEnum {
+  apps_v1 {
+    saasFiles {
+      pipelinesProvider {
+        labels
+      }
+    }
+  }
+}

tests/generator/expected/pydantic_v1/empty_map_to_none/fragment.py.txt

@@ -0,0 +1,41 @@
+"""
+Generated by qenerate plugin=pydantic_v1. DO NOT MODIFY MANUALLY!
+"""
+from collections.abc import Callable  # noqa: F401 # pylint: disable=W0611
+from datetime import datetime  # noqa: F401 # pylint: disable=W0611
+from enum import Enum  # noqa: F401 # pylint: disable=W0611
+from typing import (  # noqa: F401 # pylint: disable=W0611
+    Any,
+    Optional,
+    Union,
+)
+
+from pydantic import (  # noqa: F401 # pylint: disable=W0611
+    BaseModel,
+    Extra,
+    Field,
+    Json,
+)
+
+
+class ConfiguredBaseModel(BaseModel):
+    @root_validator(pre=True)
+    def remove_empty(cls, values: dict):
+        fields = list(values.keys())
+        for field in fields:
+            value = values[field]
+            if isinstance(value, dict):
+                if not values[field]:
+                    values[field] = None
+        return values
+
+    class Config:
+        smart_union=True
+        extra=Extra.forbid
+
+
+class VaultSecret(ConfiguredBaseModel):
+    path: str = Field(..., alias="path")
+    field: str = Field(..., alias="field")
+    version: Optional[int] = Field(..., alias="version")
+    q_format: Optional[str] = Field(..., alias="format")

tests/generator/expected/pydantic_v1/empty_map_to_none/query.py.txt

@@ -0,0 +1,83 @@
+"""
+Generated by qenerate plugin=pydantic_v1. DO NOT MODIFY MANUALLY!
+"""
+from collections.abc import Callable  # noqa: F401 # pylint: disable=W0611
+from datetime import datetime  # noqa: F401 # pylint: disable=W0611
+from enum import Enum  # noqa: F401 # pylint: disable=W0611
+from typing import (  # noqa: F401 # pylint: disable=W0611
+    Any,
+    Optional,
+    Union,
+)
+
+from pydantic import (  # noqa: F401 # pylint: disable=W0611
+    BaseModel,
+    Extra,
+    Field,
+    Json,
+)
+
+
+DEFINITION = """
+query SaasFilesWithEnum {
+  apps_v1 {
+    saasFiles {
+      pipelinesProvider {
+        labels
+      }
+    }
+  }
+}
+
+"""
+
+
+class ConfiguredBaseModel(BaseModel):
+    @root_validator(pre=True)
+    def remove_empty(cls, values: dict):
+        fields = list(values.keys())
+        for field in fields:
+            value = values[field]
+            if isinstance(value, dict):
+                if not values[field]:
+                    values[field] = None
+        return values
+
+    class Config:
+        smart_union=True
+        extra=Extra.forbid
+
+
+class PipelinesProviderV1(ConfiguredBaseModel):
+    labels: Optional[Json] = Field(..., alias="labels")
+
+
+class SaasFileV2(ConfiguredBaseModel):
+    pipelines_provider: PipelinesProviderV1 = Field(..., alias="pipelinesProvider")
+
+
+class AppV1(ConfiguredBaseModel):
+    saas_files: Optional[list[Optional[SaasFileV2]]] = Field(..., alias="saasFiles")
+
+
+class SaasFilesWithEnumQueryData(ConfiguredBaseModel):
+    apps_v1: Optional[list[Optional[AppV1]]] = Field(..., alias="apps_v1")
+
+
+def query(query_func: Callable, **kwargs: Any) -> SaasFilesWithEnumQueryData:
+    """
+    This is a convenience function which queries and parses the data into
+    concrete types. It should be compatible with most GQL clients.
+    You do not have to use it to consume the generated data classes.
+    Alternatively, you can also mime and alternate the behavior
+    of this function in the caller.
+
+    Parameters:
+        query_func (Callable): Function which queries your GQL Server
+        kwargs: optional arguments that will be passed to the query function
+
+    Returns:
+        SaasFilesWithEnumQueryData: queried data parsed into generated classes
+    """
+    raw_data: dict[Any, Any] = query_func(DEFINITION, **kwargs)
+    return SaasFilesWithEnumQueryData(**raw_data)