Add support for global API prefix env variable

backend/danswer/configs/app_configs.py

@@ -9,6 +9,10 @@ from danswer.configs.constants import DocumentIndexType
 #####
 APP_HOST = "0.0.0.0"
 APP_PORT = 8080
+# API_PREFIX is used to prepend a base path for all API routes
+# generally used if using a reverse proxy which doesn't support stripping the `/api`
+# prefix from requests directed towards the API server. In these cases, set this to `/api`
+APP_API_PREFIX = os.environ.get("API_PREFIX", "")
 
 
 #####

backend/danswer/main.py

@@ -1,6 +1,10 @@
+from typing import Any
+from typing import cast
+
 import nltk  # type:ignore
 import torch
 import uvicorn
+from fastapi import APIRouter
 from fastapi import FastAPI
 from fastapi import Request
 from fastapi.exceptions import RequestValidationError
@@ -16,6 +20,7 @@ from danswer.auth.schemas import UserUpdate
 from danswer.auth.users import auth_backend
 from danswer.auth.users import fastapi_users
 from danswer.chat.personas import load_personas_from_yaml
+from danswer.configs.app_configs import APP_API_PREFIX
 from danswer.configs.app_configs import APP_HOST
 from danswer.configs.app_configs import APP_PORT
 from danswer.configs.app_configs import AUTH_TYPE
@@ -87,47 +92,73 @@ def value_error_handler(_: Request, exc: ValueError) -> JSONResponse:
     )
 
 
+def include_router_with_global_prefix_prepended(
+    application: FastAPI, router: APIRouter, **kwargs: Any
+) -> None:
+    """Adds the global prefix to all routes in the router."""
+    processed_global_prefix = f"/{APP_API_PREFIX.strip('/')}" if APP_API_PREFIX else ""
+
+    passed_in_prefix = cast(str | None, kwargs.get("prefix"))
+    if passed_in_prefix:
+        final_prefix = f"{processed_global_prefix}/{passed_in_prefix.strip('/')}"
+    else:
+        final_prefix = f"{processed_global_prefix}"
+    final_kwargs: dict[str, Any] = {
+        **kwargs,
+        "prefix": final_prefix,
+    }
+
+    application.include_router(router, **final_kwargs)
+
+
 def get_application() -> FastAPI:
     application = FastAPI(title="Danswer Backend", version=__version__)
-    application.include_router(backend_router)
+    include_router_with_global_prefix_prepended(application, backend_router)
-    application.include_router(chat_router)
+    include_router_with_global_prefix_prepended(application, chat_router)
-    application.include_router(admin_router)
+    include_router_with_global_prefix_prepended(application, admin_router)
-    application.include_router(user_router)
+    include_router_with_global_prefix_prepended(application, user_router)
-    application.include_router(connector_router)
+    include_router_with_global_prefix_prepended(application, connector_router)
-    application.include_router(credential_router)
+    include_router_with_global_prefix_prepended(application, credential_router)
-    application.include_router(cc_pair_router)
+    include_router_with_global_prefix_prepended(application, cc_pair_router)
-    application.include_router(document_set_router)
+    include_router_with_global_prefix_prepended(application, document_set_router)
-    application.include_router(slack_bot_management_router)
+    include_router_with_global_prefix_prepended(
-    application.include_router(persona_router)
+        application, slack_bot_management_router
-    application.include_router(state_router)
+    )
-    application.include_router(danswer_api_router)
+    include_router_with_global_prefix_prepended(application, persona_router)
+    include_router_with_global_prefix_prepended(application, state_router)
+    include_router_with_global_prefix_prepended(application, danswer_api_router)
 
     if AUTH_TYPE == AuthType.DISABLED:
         # Server logs this during auth setup verification step
         pass
 
     elif AUTH_TYPE == AuthType.BASIC:
-        application.include_router(
+        include_router_with_global_prefix_prepended(
+            application,
             fastapi_users.get_auth_router(auth_backend),
             prefix="/auth",
             tags=["auth"],
         )
-        application.include_router(
+        include_router_with_global_prefix_prepended(
+            application,
             fastapi_users.get_register_router(UserRead, UserCreate),
             prefix="/auth",
             tags=["auth"],
         )
-        application.include_router(
+        include_router_with_global_prefix_prepended(
+            application,
             fastapi_users.get_reset_password_router(),
             prefix="/auth",
             tags=["auth"],
         )
-        application.include_router(
+        include_router_with_global_prefix_prepended(
+            application,
             fastapi_users.get_verify_router(UserRead),
             prefix="/auth",
             tags=["auth"],
         )
-        application.include_router(
+        include_router_with_global_prefix_prepended(
+            application,
             fastapi_users.get_users_router(UserRead, UserUpdate),
             prefix="/users",
             tags=["users"],
@@ -135,7 +166,8 @@ def get_application() -> FastAPI:
 
     elif AUTH_TYPE == AuthType.GOOGLE_OAUTH:
         oauth_client = GoogleOAuth2(OAUTH_CLIENT_ID, OAUTH_CLIENT_SECRET)
-        application.include_router(
+        include_router_with_global_prefix_prepended(
+            application,
             fastapi_users.get_oauth_router(
                 oauth_client,
                 auth_backend,
@@ -149,7 +181,8 @@ def get_application() -> FastAPI:
             tags=["auth"],
         )
         # need basic auth router for `logout` endpoint
-        application.include_router(
+        include_router_with_global_prefix_prepended(
+            application,
             fastapi_users.get_logout_router(auth_backend),
             prefix="/auth",
             tags=["auth"],