FastAPI lifespan

CHANGES.md

@@ -8,6 +8,7 @@
 * remove `stac-pydantic` dependency
 * add optional `root_path` setting to specify a url path prefix to use when running the app behind a reverse proxy
 * add landing page `/`
+* use `lifespan` option instead of deprecated `@app.on_event` method to initiate/close DB connection
 
 **breaking changes**
 

docs/src/advanced/custom_search.md

@@ -1,6 +1,6 @@
 Even though `TiTiler.PgSTAC` includes default FastAPI application,
 it also can be used like a library if you want to extend or
-override default behaviour.
+override default behavior.
 
 Let's look at one such example. Imagine that we use JSON Web Token (JWT)
 based approach for authorization and every token contains information
@@ -19,6 +19,8 @@ We want our application to take this information into account while
 registering a search query. It can be done in the following way:
 
 ```python
+from contextlib import asynccontextmanager
+
 from typing import Tuple
 import json
 import jwt
@@ -27,9 +29,18 @@ from fastapi.security.utils import get_authorization_scheme_param
 from starlette.requests import Request
 from titiler.pgstac.factory import MosaicTilerFactory
 from titiler.pgstac.model import RegisterMosaic, Metadata, PgSTACSearch
-
-
-app = FastAPI()
+from titiler.pgstac.db import close_db_connection, connect_to_db
+
+@asynccontextmanager
+async def lifespan(app: FastAPI):
+    """FastAPI Lifespan."""
+    # Create Connection Pool
+    await connect_to_db(app, settings=postgres_settings)
+    yield
+    # Close the Connection Pool
+    await close_db_connection(app)
+
+app = FastAPI(lifespan=lifespan)
 
 AREAS = {
     "zone_A": {"type": "Point", "coordinates": [-41.93, -12.76]},

docs/src/tiler_factories.md

@@ -4,22 +4,24 @@
 
 ```python
 # Minimal PgSTAC Mosaic Application
+from contextlib import asynccontextmanager
+
 from fastapi import FastAPI
 from titiler.pgstac.db import close_db_connection, connect_to_db
 from titiler.pgstac.factory import MosaicTilerFactory
 
-app = FastAPI()
-
-@app.on_event("startup")
-async def startup_event() -> None:
-    """Connect to database on startup."""
+@asynccontextmanager
+async def lifespan(app: FastAPI):
+    """FastAPI Lifespan."""
+    # Create Connection Pool
     await connect_to_db(app)
-
-@app.on_event("shutdown")
-async def shutdown_event() -> None:
-    """Close database connection."""
+    yield
+    # Close the Connection Pool
     await close_db_connection(app)
 
+
+app = FastAPI(lifespan=lifespan)
+
 mosaic = MosaicTilerFactory()
 app.include_router(mosaic.router)
 ```
@@ -45,6 +47,8 @@ This custom `path_dependency` will connect to PgSTAC directly to fetch the STAC
 
 ```python
 # Minimal PgSTAC Item Application
+from contextlib import asynccontextmanager
+
 from fastapi import FastAPI
 
 from titiler.core.factory import MultiBaseTilerFactory
@@ -53,18 +57,19 @@ from titiler.pgstac.db import close_db_connection, connect_to_db
 from titiler.pgstac.dependencies import ItemPathParams
 from titiler.pgstac.reader import PgSTACReader
 
-app = FastAPI()
 
-@app.on_event("startup")
-async def startup_event() -> None:
-    """Connect to database on startup."""
+@asynccontextmanager
+async def lifespan(app: FastAPI):
+    """FastAPI Lifespan."""
+    # Create Connection Pool
     await connect_to_db(app)
-
-@app.on_event("shutdown")
-async def shutdown_event() -> None:
-    """Close database connection."""
+    yield
+    # Close the Connection Pool
     await close_db_connection(app)
 
+
+app = FastAPI(lifespan=lifespan)
+
 item = MultiBaseTilerFactory(
     reader=PgSTACReader,
     path_dependency=ItemPathParams,

titiler/pgstac/main.py

@@ -1,6 +1,7 @@
 """TiTiler+PgSTAC FastAPI application."""
 
 import logging
+from contextlib import asynccontextmanager
 from typing import Dict
 
 import jinja2
@@ -26,7 +27,7 @@
 from titiler.pgstac.dependencies import ItemPathParams
 from titiler.pgstac.factory import MosaicTilerFactory
 from titiler.pgstac.reader import PgSTACReader
-from titiler.pgstac.settings import ApiSettings
+from titiler.pgstac.settings import ApiSettings, PostgresSettings
 
 logging.getLogger("botocore.credentials").disabled = True
 logging.getLogger("botocore.utils").disabled = True
@@ -38,8 +39,20 @@
 )  # type:ignore
 
 
+postgres_settings = PostgresSettings()
 settings = ApiSettings()
 
+
+@asynccontextmanager
+async def lifespan(app: FastAPI):
+    """FastAPI Lifespan."""
+    # Create Connection Pool
+    await connect_to_db(app, settings=postgres_settings)
+    yield
+    # Close the Connection Pool
+    await close_db_connection(app)
+
+
 app = FastAPI(
     title=settings.name,
     openapi_url="/api",
@@ -56,21 +69,9 @@
     """,
     version=titiler_pgstac_version,
     root_path=settings.root_path,
+    lifespan=lifespan,
 )
 
-
-@app.on_event("startup")
-async def startup_event() -> None:
-    """Connect to database on startup."""
-    await connect_to_db(app)
-
-
-@app.on_event("shutdown")
-async def shutdown_event() -> None:
-    """Close database connection."""
-    await close_db_connection(app)
-
-
 add_exception_handlers(app, DEFAULT_STATUS_CODES)
 add_exception_handlers(app, MOSAIC_STATUS_CODES)