feat(auth): build authz middlware from FastAPI config

bento_lib/auth/middleware/fastapi.py

@@ -1,4 +1,5 @@
 import logging
+import re
 
 from fastapi import Depends, FastAPI, Request, Response, status
 from fastapi.responses import JSONResponse
@@ -8,6 +9,7 @@
 from bento_lib.auth.middleware.base import BaseAuthMiddleware
 from bento_lib.auth.permissions import Permission
 from bento_lib.auth.resources import RESOURCE_EVERYTHING
+from bento_lib.config.pydantic import BentoFastAPIBaseConfig
 from bento_lib.responses.errors import http_error
 
 __all__ = [
@@ -16,6 +18,24 @@
 
 
 class FastApiAuthMiddleware(BaseAuthMiddleware):
+    @classmethod
+    def build_from_fastapi_pydantic_config(cls, config: BentoFastAPIBaseConfig, logger: logging.Logger, **kwargs):
+        """
+        Build a FastAPI authorization middlware instance from a Bento Pydantic FastAPI config instance and a logger
+        instance. This automatically exempts the FastAPI-generated docs OpenAPI schema paths from requiring
+        authorization.
+        :param config: instance of the FastAPI subclass of the Bento Pydantic config class.
+        :param logger: A Python logger to instantiate the FastAPI authorization middlware with.
+        :param kwargs: Keyword arguments to pass to the FastAPI authorization middleware constructor.
+        :return: An instance of the authorization middleware.
+        """
+        exempt_request_patterns = (
+            (r"GET", re.escape(config.service_docs_path)),
+            (r"GET", re.escape(config.service_openapi_path)),
+            *kwargs.pop("exempt_request_patterns", ()),
+        )
+        return cls.build_from_pydantic_config(config, logger, exempt_request_patterns=exempt_request_patterns, **kwargs)
+
     def attach(self, app: FastAPI):
         """
         Attach the middleware to an application. Must be called in order for requests to be checked.

tests/test_platform_fastapi.py

@@ -105,7 +105,7 @@ def get_403():
     bento_authz_service_url="https://bento-auth.local",
     cors_origins=("*",),
 )
-auth_middleware = FastApiAuthMiddleware.build_from_pydantic_config(
+auth_middleware = FastApiAuthMiddleware.build_from_fastapi_pydantic_config(
     app_test_auth_config,
     logger,
     include_request_patterns=authz_test_include_patterns,
@@ -327,6 +327,18 @@ def test_fastapi_auth_public(fastapi_client_auth: TestClient):
     rd2 = r.json()
     assert rd == rd2
 
+    # can get the FastAPI docs
+    r = fastapi_client_auth.get("/docs")
+    assert r.status_code == 200
+
+    # can get the OpenAPI schema
+    r = fastapi_client_auth.get("/openapi.json")
+    assert r.status_code == 200
+
+    # can post to the exempted post endpoint
+    r = fastapi_client_auth.post("/post-exempted", json=TEST_AUTHZ_VALID_POST_BODY)
+    assert r.status_code == 200
+
     # can post to the public post endpoint
     r = fastapi_client_auth.post("/post-public", json=TEST_AUTHZ_VALID_POST_BODY)
     assert r.status_code == 200