AIP-84 Get Configs / Get Config Value (#43841)

* AIP-84 Get Config

* Fix section param type and text format

* Add test for Get Config

* Consolidate redundant for check expose config

* Add `Accept` header depends for Json and Text

* Refactor config, dag_source with common header

* Refactor test_config with non-sensitive-only case

* Fix OpenAPI schema for Headers, Get Config

* Refactor test_config

- add `HEADERS_NONE` and `HEADERS_ANY` cases
- modularize common json response cases
- add `_validate_response` common method

* Fix style by ruff format

airflow/api_connexion/endpoints/config_endpoint.py

@@ -25,6 +25,7 @@
 from airflow.api_connexion.schemas.config_schema import Config, ConfigOption, ConfigSection, config_schema
 from airflow.configuration import conf
 from airflow.settings import json
+from airflow.utils.api_migration import mark_fastapi_migration_done
 
 LINE_SEP = "\n"  # `\n` cannot appear in f-strings
 
@@ -65,6 +66,7 @@ def _config_to_json(config: Config) -> str:
     return json.dumps(config_schema.dump(config), indent=4)
 
 
+@mark_fastapi_migration_done
 @security.requires_access_configuration("GET")
 def get_config(*, section: str | None = None) -> Response:
     """Get current configuration."""
@@ -102,6 +104,7 @@ def get_config(*, section: str | None = None) -> Response:
         )
 
 
+@mark_fastapi_migration_done
 @security.requires_access_configuration("GET")
 def get_value(*, section: str, option: str) -> Response:
     serializer = {

airflow/api_fastapi/common/headers.py

@@ -0,0 +1,48 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+from __future__ import annotations
+
+from fastapi import Depends, Header, HTTPException, status
+from typing_extensions import Annotated
+
+from airflow.api_fastapi.common.types import Mimetype
+
+
+def header_accept_json_or_text_depends(
+    accept: Annotated[
+        str,
+        Header(
+            json_schema_extra={
+                "type": "string",
+                "enum": [Mimetype.JSON, Mimetype.TEXT, Mimetype.ANY],
+            }
+        ),
+    ] = Mimetype.ANY,
+) -> Mimetype:
+    if accept.startswith(Mimetype.ANY):
+        return Mimetype.ANY
+    if accept.startswith(Mimetype.JSON):
+        return Mimetype.JSON
+    if accept.startswith(Mimetype.TEXT):
+        return Mimetype.TEXT
+    raise HTTPException(
+        status_code=status.HTTP_406_NOT_ACCEPTABLE,
+        detail="Only application/json or text/plain is supported",
+    )
+
+
+HeaderAcceptJsonOrText = Annotated[Mimetype, Depends(header_accept_json_or_text_depends)]

airflow/api_fastapi/common/types.py

@@ -17,6 +17,7 @@
 from __future__ import annotations
 
 from datetime import timedelta
+from enum import Enum
 from typing import Annotated
 
 from pydantic import AfterValidator, AliasGenerator, AwareDatetime, BaseModel, BeforeValidator, ConfigDict
@@ -56,3 +57,11 @@ class TimeDelta(BaseModel):
 
 
 TimeDeltaWithValidation = Annotated[TimeDelta, BeforeValidator(_validate_timedelta_field)]
+
+
+class Mimetype(str, Enum):
+    """Mimetype for the `Content-Type` header."""
+
+    TEXT = "text/plain"
+    JSON = "application/json"
+    ANY = "*/*"

airflow/api_fastapi/core_api/datamodels/config.py

@@ -0,0 +1,64 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+from __future__ import annotations
+
+from pydantic import BaseModel
+
+
+class ConfigOption(BaseModel):
+    """Config option."""
+
+    key: str
+    value: str | tuple[str, str]
+
+    @property
+    def text_format(self):
+        if isinstance(self.value, tuple):
+            return f"{self.key} = {self.value[0]} {self.value[1]}"
+        return f"{self.key} = {self.value}"
+
+
+class ConfigSection(BaseModel):
+    """Config Section Schema."""
+
+    name: str
+    options: list[ConfigOption]
+
+    @property
+    def text_format(self):
+        """
+        Convert the config section to text format.
+
+        Example:
+        ```
+        [section_name]
+        key1 = value1
+        key2 = value2
+        ```
+        """
+        return f"[{self.name}]\n" + "\n".join(option.text_format for option in self.options) + "\n"
+
+
+class Config(BaseModel):
+    """List of config sections with their options."""
+
+    sections: list[ConfigSection]
+
+    @property
+    def text_format(self):
+        # convert all config sections to text
+        return "\n".join(section.text_format for section in self.sections)

airflow/api_fastapi/core_api/openapi/v1-generated.yaml

@@ -1683,6 +1683,10 @@ paths:
         required: false
         schema:
           type: string
+          enum:
+          - application/json
+          - text/plain
+          - '*/*'
           default: '*/*'
           title: Accept
       responses:
@@ -1785,6 +1789,163 @@ paths:
             application/json:
               schema:
                 $ref: '#/components/schemas/HTTPValidationError'
+  /public/config/:
+    get:
+      tags:
+      - Config
+      summary: Get Config
+      operationId: get_config
+      parameters:
+      - name: section
+        in: query
+        required: false
+        schema:
+          anyOf:
+          - type: string
+          - type: 'null'
+          title: Section
+      - name: accept
+        in: header
+        required: false
+        schema:
+          type: string
+          enum:
+          - application/json
+          - text/plain
+          - '*/*'
+          default: '*/*'
+          title: Accept
+      responses:
+        '200':
+          description: Successful Response
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Config'
+            text/plain:
+              schema:
+                type: string
+                example: '[core]
+
+                  dags_folder = /opt/airflow/dags
+
+                  base_log_folder = /opt/airflow/logs
+
+
+                  [smtp]
+
+                  smtp_host = localhost
+
+                  smtp_mail_from = airflow@example.com
+
+                  '
+        '401':
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/HTTPExceptionResponse'
+          description: Unauthorized
+        '403':
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/HTTPExceptionResponse'
+          description: Forbidden
+        '404':
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/HTTPExceptionResponse'
+          description: Not Found
+        '406':
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/HTTPExceptionResponse'
+          description: Not Acceptable
+        '422':
+          description: Validation Error
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/HTTPValidationError'
+  /public/config/section/{section}/option/{option}:
+    get:
+      tags:
+      - Config
+      summary: Get Config Value
+      operationId: get_config_value
+      parameters:
+      - name: section
+        in: path
+        required: true
+        schema:
+          type: string
+          title: Section
+      - name: option
+        in: path
+        required: true
+        schema:
+          type: string
+          title: Option
+      - name: accept
+        in: header
+        required: false
+        schema:
+          type: string
+          enum:
+          - application/json
+          - text/plain
+          - '*/*'
+          default: '*/*'
+          title: Accept
+      responses:
+        '200':
+          description: Successful Response
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Config'
+            text/plain:
+              schema:
+                type: string
+                example: '[core]
+
+                  dags_folder = /opt/airflow/dags
+
+                  base_log_folder = /opt/airflow/logs
+
+                  '
+        '401':
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/HTTPExceptionResponse'
+          description: Unauthorized
+        '403':
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/HTTPExceptionResponse'
+          description: Forbidden
+        '404':
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/HTTPExceptionResponse'
+          description: Not Found
+        '406':
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/HTTPExceptionResponse'
+          description: Not Acceptable
+        '422':
+          description: Validation Error
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/HTTPValidationError'
   /public/dagWarnings:
     get:
       tags:
@@ -4593,6 +4754,55 @@ components:
       - status
       title: BaseInfoSchema
       description: Base status field for metadatabase and scheduler.
+    Config:
+      properties:
+        sections:
+          items:
+            $ref: '#/components/schemas/ConfigSection'
+          type: array
+          title: Sections
+      type: object
+      required:
+      - sections
+      title: Config
+      description: List of config sections with their options.
+    ConfigOption:
+      properties:
+        key:
+          type: string
+          title: Key
+        value:
+          anyOf:
+          - type: string
+          - prefixItems:
+            - type: string
+            - type: string
+            type: array
+            maxItems: 2
+            minItems: 2
+          title: Value
+      type: object
+      required:
+      - key
+      - value
+      title: ConfigOption
+      description: Config option.
+    ConfigSection:
+      properties:
+        name:
+          type: string
+          title: Name
+        options:
+          items:
+            $ref: '#/components/schemas/ConfigOption'
+          type: array
+          title: Options
+      type: object
+      required:
+      - name
+      - options
+      title: ConfigSection
+      description: Config Section Schema.
     ConnectionBody:
       properties:
         connection_id: