feat: python rtl optional config ApiSettings init parameter (#996)

This PR adds an optional config_settings parameter to the python sdk init functions. It is up to the sdk user to provide a valid implementation of the ApiSettings class.

Author: kevin-wallace-wpro

Diff for: python/README.rst

@@ -99,8 +99,13 @@ Install looker_sdk using pipenv
 Configuring the SDK
 ===================
 
-The SDK supports configuration through a ``.ini`` file on disk as well
-as `setting environment variables <https://github.com/looker-open-source/sdk-codegen#environment-variable-configuration>`_ (the latter override the former).
+The SDK supports configuration through
+
+1. an ``.ini`` file on disk
+2. `setting environment variables <https://github.com/looker-open-source/sdk-codegen#environment-variable-configuration>`_
+3. providing your own implementation of the ApiSettings class
+
+. The latter override the former.
 
 **Note**: The ``.ini`` configuration for the Looker SDK is a sample
 implementation intended to speed up the initial development of python
@@ -132,6 +137,34 @@ example file:
 For any ``.ini`` setting you can use an environment variable instead. It takes the form of
 ``LOOKERSDK_<UPPERCASE-SETTING-FROM-INI>`` e.g. ``LOOKERSDK_CLIENT_SECRET``
 
+A final option is to provide your own implementation of the ApiSettings class. It is easiest to subclass ``api_settings.ApiSettings`` and override the ``read_config`` function (don't forget a call to ``super().read_config()`` if appropriate, Example below). However, at a minimum your class must implement the `api_settings.PApiSettings` protocol.
+
+
+.. code-block:: python
+
+    import os
+    import looker_sdk
+    from looker_sdk import api_settings
+
+    class MyApiSettings(api_settings.ApiSettings):
+        def __init__(self, *args, **kw_args):
+            self.my_var = kw_args.pop("my_var")
+            super().__init__(*args, **kw_args)
+
+        def read_config(self) -> api_settings.SettingsConfig:
+            config = super().read_config()
+            # See api_settings.SettingsConfig for required fields
+            if self.my_var == "foo":
+                config["client_id"] = os.getenv("FOO_CLIENT")
+                config["client_secret"] = os.getenv("FOO_SECRET")
+            else:
+                config["client_id"] = os.getenv("BAR_CLIENT")
+                config["client_secret"] = os.getenv("BAR_SECRET")
+            return config
+
+    sdk = looker_sdk.init40(config_settings=MyApiSettings(my_var="foo"))
+    ...
+
 
 Code example
 ============

Diff for: python/looker_sdk/__init__.py

@@ -49,10 +49,14 @@ def _settings(
 
 
 def init31(
-    config_file: str = "looker.ini", section: Optional[str] = None
+    config_file: str = "looker.ini",
+    section: Optional[str] = None,
+    config_settings: Optional[api_settings.ApiSettings] = None,
 ) -> methods31.Looker31SDK:
     """Default dependency configuration"""
-    settings = _settings(config_file, section)
+    settings = (
+        _settings(config_file, section) if config_settings is None else config_settings
+    )
     settings.is_configured()
     transport = requests_transport.RequestsTransport.configure(settings)
     return methods31.Looker31SDK(
@@ -65,10 +69,14 @@ def init31(
 
 
 def init40(
-    config_file: str = "looker.ini", section: Optional[str] = None
+    config_file: str = "looker.ini",
+    section: Optional[str] = None,
+    config_settings: Optional[api_settings.ApiSettings] = None,
 ) -> methods40.Looker40SDK:
     """Default dependency configuration"""
-    settings = _settings(config_file, section)
+    settings = (
+        _settings(config_file, section) if config_settings is None else config_settings
+    )
     settings.is_configured()
     transport = requests_transport.RequestsTransport.configure(settings)
     return methods40.Looker40SDK(

Diff for: python/looker_sdk/rtl/api_settings.py

@@ -26,19 +26,30 @@
 import configparser as cp
 import os
 import sys
-from typing import Dict, Optional, Set
+from typing import Dict, Optional, Set, cast
 import warnings
 
 from looker_sdk.rtl import transport
 
 if sys.version_info >= (3, 8):
-    from typing import Protocol
+    from typing import Protocol, TypedDict
 else:
-    from typing_extensions import Protocol
+    from typing_extensions import Protocol, TypedDict
+from typing_extensions import Required
+
+
+class SettingsConfig(TypedDict, total=False):
+    client_id: Required[str]
+    client_secret: Required[str]
+    base_url: str
+    verify_ssl: str
+    timeout: str
+    redirect_uri: str
+    looker_url: str
 
 
 class PApiSettings(transport.PTransportSettings, Protocol):
-    def read_config(self) -> Dict[str, str]:
+    def read_config(self) -> SettingsConfig:
         ...
 
 
@@ -93,23 +104,27 @@ def __init__(
         if sdk_version:
             self.agent_tag += f" {sdk_version}"
 
-    def read_config(self) -> Dict[str, str]:
+    def read_config(self) -> SettingsConfig:
         cfg_parser = cp.ConfigParser()
+        data: SettingsConfig = {
+            "client_id": "",
+            "client_secret": "",
+        }
         try:
             config_file = open(self.filename)
         except FileNotFoundError:
-            data: Dict[str, str] = {}
+            pass
         else:
             cfg_parser.read_file(config_file)
             config_file.close()
             # If section is not specified, use first section in file
             section = self.section or cfg_parser.sections()[0]
             if not cfg_parser.has_section(section):
                 raise cp.NoSectionError(section)
-            data = dict(cfg_parser[section])
+            self._override_settings(data, dict(cfg_parser[section]))
 
         if self.env_prefix:
-            data.update(self._override_from_env())
+            self._override_settings(data, self._override_from_env())
         return self._clean_input(data)
 
     @staticmethod
@@ -122,6 +137,15 @@ def _bool(val: str) -> bool:
             raise TypeError
         return converted
 
+    def _override_settings(
+        self, data: SettingsConfig, overrides: Dict[str, str]
+    ) -> SettingsConfig:
+        # https://github.com/python/mypy/issues/6262
+        for setting in SettingsConfig.__annotations__.keys(): # type: ignore
+            if setting in overrides:
+                data[setting] = overrides[setting] # type: ignore
+        return data
+
     def _override_from_env(self) -> Dict[str, str]:
         overrides = {}
         base_url = os.getenv(f"{self.env_prefix}_BASE_URL")
@@ -146,7 +170,7 @@ def _override_from_env(self) -> Dict[str, str]:
 
         return overrides
 
-    def _clean_input(self, data: Dict[str, str]) -> Dict[str, str]:
+    def _clean_input(self, data: SettingsConfig) -> SettingsConfig:
         """Remove surrounding quotes and discard empty strings.
         """
         cleaned = {}
@@ -157,6 +181,8 @@ def _clean_input(self, data: Dict[str, str]) -> Dict[str, str]:
                         f"'{setting}' config setting is deprecated"
                     )
                 )
+            if not isinstance(value, str):
+                continue
             # Remove empty setting values
             if value in ['""', "''", ""]:
                 continue
@@ -165,4 +191,4 @@ def _clean_input(self, data: Dict[str, str]) -> Dict[str, str]:
                 cleaned[setting] = value.strip("\"'")
             else:
                 cleaned[setting] = value
-        return cleaned
+        return cast(SettingsConfig, cleaned)

Diff for: python/looker_sdk/rtl/auth_session.py

@@ -273,8 +273,8 @@ def __init__(
         # would have prefered using setattr(self, required, ...) in loop above
         # but mypy can't follow it
         self.client_id = config_data["client_id"]
-        self.redirect_uri = config_data["redirect_uri"]
-        self.looker_url = config_data["looker_url"]
+        self.redirect_uri = config_data.get("redirect_uri", "")
+        self.looker_url = config_data.get("looker_url", "")
         self.code_verifier = ""
 
     def create_auth_code_request_url(self, scope: str, state: str) -> str:

Diff for: python/setup.py

@@ -32,14 +32,14 @@
 VERSION = version["__version__"]
 REQUIRES = [
     "requests >= 2.22",
+    "typing-extensions >= 4.1.1",
     # Python 3.6
     "attrs >= 18.2.0;python_version<'3.7'",
     "cattrs < 1.1.0;python_version<'3.7'",
     "python-dateutil;python_version<'3.7'",
     # Python 3.7+
     "attrs >= 20.1.0;python_version>='3.7'",
     "cattrs >= 1.3;python_version>='3.7'",
-    "typing-extensions;python_version<'3.8'",
 ]