Merge pull request #3588 from lonvia/optional-reverse-api

Add support for adding endpoints to server conditionally

Author: lonvia

src/nominatim_api/server/falcon/server.py

@@ -147,12 +147,36 @@ async def process_response(self, req: Request, resp: Response,
                       f'{resource.name} "{params}"\n')
 
 
-class APIShutdown:
-    """ Middleware that closes any open database connections.
+class APIMiddleware:
+    """ Middleware managing the Nominatim database connection.
     """
 
-    def __init__(self, api: NominatimAPIAsync) -> None:
-        self.api = api
+    def __init__(self, project_dir: Path, environ: Optional[Mapping[str, str]]) -> None:
+        self.api = NominatimAPIAsync(project_dir, environ)
+        self.app: Optional[App] = None
+
+    @property
+    def config(self) -> Configuration:
+        """ Get the configuration for Nominatim.
+        """
+        return self.api.config
+
+    def set_app(self, app: App) -> None:
+        """ Set the Falcon application this middleware is connected to.
+        """
+        self.app = app
+
+    async def process_startup(self, *_: Any) -> None:
+        """ Process the ASGI lifespan startup event.
+        """
+        assert self.app is not None
+        legacy_urls = self.api.config.get_bool('SERVE_LEGACY_URLS')
+        formatter = load_format_dispatcher('v1', self.api.config.project_dir)
+        for name, func in await api_impl.get_routes(self.api):
+            endpoint = EndpointWrapper(name, func, self.api, formatter)
+            self.app.add_route(f"/{name}", endpoint)
+            if legacy_urls:
+                self.app.add_route(f"/{name}.php", endpoint)
 
     async def process_shutdown(self, *_: Any) -> None:
         """Process the ASGI lifespan shutdown event.
@@ -164,28 +188,22 @@ def get_application(project_dir: Path,
                     environ: Optional[Mapping[str, str]] = None) -> App:
     """ Create a Nominatim Falcon ASGI application.
     """
-    api = NominatimAPIAsync(project_dir, environ)
+    apimw = APIMiddleware(project_dir, environ)
 
-    middleware: List[object] = [APIShutdown(api)]
-    log_file = api.config.LOG_FILE
+    middleware: List[object] = [apimw]
+    log_file = apimw.config.LOG_FILE
     if log_file:
         middleware.append(FileLoggingMiddleware(log_file))
 
-    app = App(cors_enable=api.config.get_bool('CORS_NOACCESSCONTROL'),
+    app = App(cors_enable=apimw.config.get_bool('CORS_NOACCESSCONTROL'),
               middleware=middleware)
+
+    apimw.set_app(app)
     app.add_error_handler(HTTPNominatimError, nominatim_error_handler)
     app.add_error_handler(TimeoutError, timeout_error_handler)
     # different from TimeoutError in Python <= 3.10
     app.add_error_handler(asyncio.TimeoutError, timeout_error_handler)  # type: ignore[arg-type]
 
-    legacy_urls = api.config.get_bool('SERVE_LEGACY_URLS')
-    formatter = load_format_dispatcher('v1', project_dir)
-    for name, func in api_impl.ROUTES:
-        endpoint = EndpointWrapper(name, func, api, formatter)
-        app.add_route(f"/{name}", endpoint)
-        if legacy_urls:
-            app.add_route(f"/{name}.php", endpoint)
-
     return app
 
 

src/nominatim_api/server/starlette/server.py

@@ -7,10 +7,12 @@
 """
 Server implementation using the starlette webserver framework.
 """
-from typing import Any, Optional, Mapping, Callable, cast, Coroutine, Dict, Awaitable
+from typing import Any, Optional, Mapping, Callable, cast, Coroutine, Dict, \
+                   Awaitable, AsyncIterator
 from pathlib import Path
 import datetime as dt
 import asyncio
+import contextlib
 
 from starlette.applications import Starlette
 from starlette.routing import Route
@@ -66,7 +68,7 @@ def config(self) -> Configuration:
         return cast(Configuration, self.request.app.state.API.config)
 
     def formatting(self) -> FormatDispatcher:
-        return cast(FormatDispatcher, self.request.app.state.API.formatter)
+        return cast(FormatDispatcher, self.request.app.state.formatter)
 
 
 def _wrap_endpoint(func: EndpointFunc)\
@@ -132,14 +134,6 @@ def get_application(project_dir: Path,
     """
     config = Configuration(project_dir, environ)
 
-    routes = []
-    legacy_urls = config.get_bool('SERVE_LEGACY_URLS')
-    for name, func in api_impl.ROUTES:
-        endpoint = _wrap_endpoint(func)
-        routes.append(Route(f"/{name}", endpoint=endpoint))
-        if legacy_urls:
-            routes.append(Route(f"/{name}.php", endpoint=endpoint))
-
     middleware = []
     if config.get_bool('CORS_NOACCESSCONTROL'):
         middleware.append(Middleware(CORSMiddleware,
@@ -156,14 +150,26 @@ def get_application(project_dir: Path,
         asyncio.TimeoutError: timeout_error
     }
 
-    async def _shutdown() -> None:
+    @contextlib.asynccontextmanager
+    async def lifespan(app: Starlette) -> AsyncIterator[Any]:
+        app.state.API = NominatimAPIAsync(project_dir, environ)
+        config = app.state.API.config
+
+        legacy_urls = config.get_bool('SERVE_LEGACY_URLS')
+        for name, func in await api_impl.get_routes(app.state.API):
+            endpoint = _wrap_endpoint(func)
+            app.routes.append(Route(f"/{name}", endpoint=endpoint))
+            if legacy_urls:
+                app.routes.append(Route(f"/{name}.php", endpoint=endpoint))
+
+        yield
+
         await app.state.API.close()
 
-    app = Starlette(debug=debug, routes=routes, middleware=middleware,
+    app = Starlette(debug=debug, middleware=middleware,
                     exception_handlers=exceptions,
-                    on_shutdown=[_shutdown])
+                    lifespan=lifespan)
 
-    app.state.API = NominatimAPIAsync(project_dir, environ)
     app.state.formatter = load_format_dispatcher('v1', project_dir)
 
     return app

src/nominatim_api/v1/__init__.py

@@ -8,4 +8,4 @@
 Implementation of API version v1 (aka the legacy version).
 """
 
-from .server_glue import ROUTES as ROUTES
+from .server_glue import get_routes as get_routes

src/nominatim_api/v1/server_glue.py

@@ -8,7 +8,7 @@
 Generic part of the server implementation of the v1 API.
 Combine with the scaffolding provided for the various Python ASGI frameworks.
 """
-from typing import Optional, Any, Type, Dict, cast
+from typing import Optional, Any, Type, Dict, cast, Sequence, Tuple
 from functools import reduce
 import dataclasses
 from urllib.parse import urlencode
@@ -25,7 +25,8 @@
 from ..localization import Locales
 from . import helpers
 from ..server import content_types as ct
-from ..server.asgi_adaptor import ASGIAdaptor
+from ..server.asgi_adaptor import ASGIAdaptor, EndpointFunc
+from ..sql.async_core_library import PGCORE_ERROR
 
 
 def build_response(adaptor: ASGIAdaptor, output: str, status: int = 200,
@@ -417,12 +418,25 @@ async def polygons_endpoint(api: NominatimAPIAsync, params: ASGIAdaptor) -> Any:
     return build_response(params, params.formatting().format_result(results, fmt, {}))
 
 
-ROUTES = [
-    ('status', status_endpoint),
-    ('details', details_endpoint),
-    ('reverse', reverse_endpoint),
-    ('lookup', lookup_endpoint),
-    ('search', search_endpoint),
-    ('deletable', deletable_endpoint),
-    ('polygons', polygons_endpoint),
-]
+async def get_routes(api: NominatimAPIAsync) -> Sequence[Tuple[str, EndpointFunc]]:
+    routes = [
+        ('status', status_endpoint),
+        ('details', details_endpoint),
+        ('reverse', reverse_endpoint),
+        ('lookup', lookup_endpoint),
+        ('deletable', deletable_endpoint),
+        ('polygons', polygons_endpoint),
+    ]
+
+    def has_search_name(conn: sa.engine.Connection) -> bool:
+        insp = sa.inspect(conn)
+        return insp.has_table('search_name')
+
+    try:
+        async with api.begin() as conn:
+            if await conn.connection.run_sync(has_search_name):
+                routes.append(('search', search_endpoint))
+    except (PGCORE_ERROR, sa.exc.OperationalError):
+        pass  # ignored
+
+    return routes