Change to app factory pattern (#224)

* Change to app factory pattern. The factory pattern is supported by uvicorn, gunicorn, and FastAPI. It allows parameterised creation of the App object among other benefits.

* update Dockerfile and prez tests to use factory pattern

Dockerfile

@@ -53,4 +53,4 @@ WORKDIR /app
 # prez module is already built as a package and installed in $VIRTUAL_ENV as a library
 COPY main.py pyproject.toml ./
 
-ENTRYPOINT uvicorn prez.app:app --host=${HOST:-0.0.0.0} --port=${PORT:-8000} --proxy-headers
+ENTRYPOINT uvicorn prez.app:assemble_app --factory --host=${HOST:-0.0.0.0} --port=${PORT:-8000} --proxy-headers

main.py

@@ -10,4 +10,4 @@
 
     port = int(environ.get("PREZ_DEV_SERVER_PORT", 8000))
 
-    uvicorn.run("prez.app:app", port=port, reload=True)
+    uvicorn.run("prez.app:assemble_app", factory=True, port=port, reload=True)

prez/app.py

@@ -1,14 +1,14 @@
 import logging
-import os
+from functools import partial
 from textwrap import dedent
-
+from typing import Optional, Dict, Union, Any
 import uvicorn
 from fastapi import FastAPI
 from fastapi.openapi.utils import get_openapi
 from rdflib import Graph
 from starlette.middleware.cors import CORSMiddleware
 
-from prez.config import settings
+from prez.config import settings, Settings
 from prez.dependencies import (
     get_async_http_client,
     get_pyoxi_store,
@@ -53,34 +53,28 @@
 from prez.services.search_methods import get_all_search_methods
 from prez.sparql.methods import RemoteSparqlRepo, PyoxigraphRepo, OxrdflibRepo
 
-app = FastAPI(
-    exception_handlers={
-        400: catch_400,
-        404: catch_404,
-        500: catch_500,
-        ClassNotFoundException: catch_class_not_found_exception,
-        URINotFoundException: catch_uri_not_found_exception,
-        NoProfilesException: catch_no_profiles_exception,
-    }
-)
-
 
-app.include_router(cql_router)
-app.include_router(management_router)
-app.include_router(object_router)
-app.include_router(sparql_router)
-app.include_router(search_router)
-app.include_router(profiles_router)
-if "CatPrez" in settings.prez_flavours:
-    app.include_router(catprez_router)
-if "VocPrez" in settings.prez_flavours:
-    app.include_router(vocprez_router)
-if "SpacePrez" in settings.prez_flavours:
-    app.include_router(spaceprez_router)
-app.include_router(identifier_router)
+def prez_open_api_metadata(
+    title: str,
+    description: str,
+    version: str,
+    contact: Optional[Dict[str, Union[str, Any]]],
+    _app: FastAPI,
+):
+    return get_openapi(
+        title=title,
+        description=description,
+        version=version,
+        contact=contact,
+        license_info=_app.license_info,
+        openapi_version=_app.openapi_version,
+        terms_of_service=_app.terms_of_service,
+        tags=_app.openapi_tags,
+        servers=_app.servers,
+        routes=_app.routes,
+    )
 
 
-@app.middleware("http")
 async def add_cors_headers(request, call_next):
     response = await call_next(request)
     response.headers["Access-Control-Allow-Origin"] = "*"
@@ -90,69 +84,45 @@ async def add_cors_headers(request, call_next):
     return response
 
 
-app.add_middleware(
-    CORSMiddleware,
-    allow_origins=["*"],
-    allow_credentials=True,
-    allow_methods=["*"],
-    allow_headers=["*"],
-    expose_headers=["*"],
-)
-
-
-def prez_open_api_metadata():
-    return get_openapi(
-        title=settings.prez_title,
-        version=settings.prez_version,
-        description=settings.prez_desc,
-        routes=app.routes,
-    )
-
-
-app.openapi = prez_open_api_metadata
-
-
-@app.on_event("startup")
-async def app_startup():
+async def app_startup(_settings: Settings, _app: FastAPI):
     """
     This function runs at startup and will continually poll the separate backends until their SPARQL endpoints
     are available. Initial caching can be triggered within the try block. NB this function does not check that data is
     appropriately configured at the SPARQL endpoint(s), only that the SPARQL endpoint(s) are reachable.
     """
-    setup_logger(settings)
+    setup_logger(_settings)
     log = logging.getLogger("prez")
     log.info("Starting up")
 
-    if settings.sparql_repo_type == "pyoxigraph":
-        app.state.pyoxi_store = get_pyoxi_store()
-        app.state.repo = PyoxigraphRepo(app.state.pyoxi_store)
-        await load_local_data_to_oxigraph(app.state.pyoxi_store)
-    elif settings.sparql_repo_type == "oxrdflib":
-        app.state.oxrdflib_store = get_oxrdflib_store()
-        app.state.repo = OxrdflibRepo(app.state.oxrdflib_store)
-    elif settings.sparql_repo_type == "remote":
-        app.state.http_async_client = await get_async_http_client()
-        app.state.repo = RemoteSparqlRepo(app.state.http_async_client)
+    if _settings.sparql_repo_type == "pyoxigraph":
+        _app.state.pyoxi_store = get_pyoxi_store()
+        _app.state.repo = _repo = PyoxigraphRepo(_app.state.pyoxi_store)
+        await load_local_data_to_oxigraph(_app.state.pyoxi_store)
+    elif _settings.sparql_repo_type == "oxrdflib":
+        _app.state.oxrdflib_store = get_oxrdflib_store()
+        _app.state.repo = _repo = OxrdflibRepo(_app.state.oxrdflib_store)
+    elif _settings.sparql_repo_type == "remote":
+        _app.state.http_async_client = await get_async_http_client()
+        _app.state.repo = _repo = RemoteSparqlRepo(_app.state.http_async_client)
         await healthcheck_sparql_endpoints()
     else:
         raise ValueError(
             "SPARQL_REPO_TYPE must be one of 'pyoxigraph', 'oxrdflib' or 'remote'"
         )
 
-    await add_prefixes_to_prefix_graph(app.state.repo)
-    await get_all_search_methods(app.state.repo)
-    await create_profiles_graph(app.state.repo)
-    await create_endpoints_graph(app.state.repo)
-    await count_objects(app.state.repo)
+    await add_prefixes_to_prefix_graph(_repo)
+    await get_all_search_methods(_repo)
+    await create_profiles_graph(_repo)
+    await create_endpoints_graph(_repo)
+    await count_objects(_repo)
     await populate_api_info()
     await add_common_context_ontologies_to_tbox_cache()
 
-    app.state.pyoxi_system_store = get_system_store()
-    await load_system_data_to_oxigraph(app.state.pyoxi_system_store)
+    _app.state.pyoxi_system_store = get_system_store()
+    await load_system_data_to_oxigraph(_app.state.pyoxi_system_store)
 
 
-@app.on_event("shutdown")
-async def app_shutdown():
+async def app_shutdown(_settings: Settings, _app: FastAPI):
     """
     persists caches
     close async SPARQL clients
@@ -161,8 +131,81 @@ async def app_shutdown():
     log.info("Shutting down...")
 
     # close all SPARQL async clients
-    if not settings.sparql_repo_type:
-        await app.state.http_async_client.aclose()
+    if not _settings.sparql_repo_type:
+        await _app.state.http_async_client.aclose()
+
+
+def assemble_app(
+    root_path: str = "",
+    title: Optional[str] = None,
+    description: Optional[str] = None,
+    version: Optional[str] = None,
+    local_settings: Optional[Settings] = None,
+    **kwargs
+):
+
+    _settings = local_settings if local_settings is not None else settings
+
+    if title is None:
+        title = _settings.prez_title
+    if version is None:
+        version = _settings.prez_version
+    if description is None:
+        description = _settings.prez_desc
+    contact = _settings.prez_contact
+
+    app = FastAPI(
+        root_path=root_path,
+        title=title,
+        version=version,
+        description=description,
+        contact=contact,
+        exception_handlers={
+            400: catch_400,
+            404: catch_404,
+            500: catch_500,
+            ClassNotFoundException: catch_class_not_found_exception,
+            URINotFoundException: catch_uri_not_found_exception,
+            NoProfilesException: catch_no_profiles_exception,
+        },
+        **kwargs
+    )
+
+    app.include_router(cql_router)
+    app.include_router(management_router)
+    app.include_router(object_router)
+    app.include_router(sparql_router)
+    app.include_router(search_router)
+    app.include_router(profiles_router)
+    if "CatPrez" in _settings.prez_flavours:
+        app.include_router(catprez_router)
+    if "VocPrez" in _settings.prez_flavours:
+        app.include_router(vocprez_router)
+    if "SpacePrez" in _settings.prez_flavours:
+        app.include_router(spaceprez_router)
+    app.include_router(identifier_router)
+    app.openapi = partial(
+        prez_open_api_metadata,
+        title=title,
+        description=description,
+        version=version,
+        contact=contact,
+        _app=app,
+    )
+
+    app.middleware("http")(add_cors_headers)
+
+    app.add_middleware(
+        CORSMiddleware,
+        allow_origins=["*"],
+        allow_credentials=True,
+        allow_methods=["*"],
+        allow_headers=["*"],
+        expose_headers=["*"],
+    )
+    app.on_event("startup")(partial(app_startup, _settings=_settings, _app=app))
+    app.on_event("shutdown")(partial(app_shutdown, _settings=_settings, _app=app))
+    return app
 
 
 def _get_sparql_service_description(request, format):
@@ -200,4 +243,4 @@ def _get_sparql_service_description(request, format):
 
 
 if __name__ == "__main__":
-    uvicorn.run("app:app", port=settings.port, host=settings.host)
+    uvicorn.run(assemble_app, factory=True, port=settings.port, host=settings.host)

prez/config.py

@@ -1,6 +1,6 @@
 from os import environ
 from pathlib import Path
-from typing import Optional
+from typing import Optional, Union, Any, Dict
 
 import toml
 from pydantic import BaseSettings, root_validator
@@ -58,6 +58,7 @@ class Settings(BaseSettings):
         "Knowledge Graph data which can be subset according to information profiles."
     )
     prez_version: Optional[str]
+    prez_contact: Optional[Dict[str, Union[str, Any]]]
     disable_prefix_generation: bool = False
     local_rdf_dir: str = "rdf"
 

tests/test_count.py

@@ -4,7 +4,7 @@
 from fastapi.testclient import TestClient
 from pyoxigraph.pyoxigraph import Store
 
-from prez.app import app
+from prez.app import assemble_app
 from prez.dependencies import get_repo
 from prez.sparql.methods import Repo, PyoxigraphRepo
 
@@ -32,6 +32,8 @@ def test_client(test_repo: Repo) -> TestClient:
     def override_get_repo():
         return test_repo
 
+    app = assemble_app()
+
     app.dependency_overrides[get_repo] = override_get_repo
 
     with TestClient(app) as c:

tests/test_curie_endpoint.py

@@ -1,11 +1,12 @@
 import pytest
 from fastapi.testclient import TestClient
 
-from prez.app import app
+from prez.app import assemble_app
 
 
 @pytest.fixture
 def client() -> TestClient:
+    app = assemble_app()
     testclient = TestClient(app)
 
     # Make a request for the following IRI to ensure

tests/test_dd_profiles.py

@@ -6,7 +6,7 @@
 from fastapi.testclient import TestClient
 from pyoxigraph.pyoxigraph import Store
 
-from prez.app import app
+from prez.app import assemble_app
 from prez.dependencies import get_repo
 from prez.sparql.methods import Repo, PyoxigraphRepo
 
@@ -34,6 +34,8 @@ def test_client(test_repo: Repo) -> TestClient:
     def override_get_repo():
         return test_repo
 
+    app = assemble_app()
+
     app.dependency_overrides[get_repo] = override_get_repo
 
     with TestClient(app) as c:

tests/test_endpoints_cache.py

@@ -5,7 +5,7 @@
 from pyoxigraph.pyoxigraph import Store
 from rdflib import Graph
 
-from prez.app import app
+from prez.app import assemble_app
 from prez.dependencies import get_repo
 from prez.sparql.methods import Repo, PyoxigraphRepo
 
@@ -33,6 +33,8 @@ def test_client(test_repo: Repo) -> TestClient:
     def override_get_repo():
         return test_repo
 
+    app = assemble_app()
+
     app.dependency_overrides[get_repo] = override_get_repo
 
     with TestClient(app) as c:

tests/test_endpoints_catprez.py

@@ -6,7 +6,7 @@
 from rdflib import Graph, URIRef
 from rdflib.namespace import RDF, DCAT
 
-from prez.app import app
+from prez.app import assemble_app
 from prez.dependencies import get_repo
 from prez.sparql.methods import Repo, PyoxigraphRepo
 
@@ -34,6 +34,8 @@ def client(test_repo: Repo) -> TestClient:
     def override_get_repo():
         return test_repo
 
+    app = assemble_app()
+
     app.dependency_overrides[get_repo] = override_get_repo
 
     with TestClient(app) as c:

tests/test_endpoints_management.py

@@ -5,7 +5,7 @@
 from pyoxigraph.pyoxigraph import Store
 from rdflib import Graph
 
-from prez.app import app
+from prez.app import assemble_app
 from prez.dependencies import get_repo
 from prez.reference_data.prez_ns import PREZ
 from prez.sparql.methods import Repo, PyoxigraphRepo
@@ -34,6 +34,8 @@ def client(test_repo: Repo) -> TestClient:
     def override_get_repo():
         return test_repo
 
+    app = assemble_app()
+
     app.dependency_overrides[get_repo] = override_get_repo
 
     with TestClient(app) as c: