Do not create FastAPI app until config loaded

src/blueapi/service/main.py

@@ -2,6 +2,7 @@
 from contextlib import asynccontextmanager
 
 from fastapi import (
+    APIRouter,
     BackgroundTasks,
     Body,
     Depends,
@@ -80,25 +81,34 @@ async def lifespan(app: FastAPI):
     teardown_runner()
 
 
-app = FastAPI(
-    docs_url="/docs",
-    title="BlueAPI Control",
-    lifespan=lifespan,
-    version=REST_API_VERSION,
-)
+router = APIRouter()
+
+
+def get_app():
+    app = FastAPI(
+        docs_url="/docs",
+        title="BlueAPI Control",
+        lifespan=lifespan,
+        version=REST_API_VERSION,
+    )
+    app.include_router(router)
+    app.add_exception_handler(KeyError, on_key_error_404)
+    add_api_version_header(app)
+    inject_propagated_observability_context(app)
+    return app
+
 
 TRACER = get_tracer("interface")
 
 
-@app.exception_handler(KeyError)
 async def on_key_error_404(_: Request, __: KeyError):
     return JSONResponse(
         status_code=status.HTTP_404_NOT_FOUND,
         content={"detail": "Item not found"},
     )
 
 
-@app.get("/environment", response_model=EnvironmentResponse)
+@router.get("/environment", response_model=EnvironmentResponse)
 @start_as_current_span(TRACER, "runner")
 def get_environment(
     runner: WorkerDispatcher = Depends(_runner),
@@ -107,7 +117,7 @@ def get_environment(
     return runner.state
 
 
-@app.delete("/environment", response_model=EnvironmentResponse)
+@router.delete("/environment", response_model=EnvironmentResponse)
 async def delete_environment(
     background_tasks: BackgroundTasks,
     runner: WorkerDispatcher = Depends(_runner),
@@ -119,14 +129,14 @@ async def delete_environment(
     return EnvironmentResponse(initialized=False)
 
 
-@app.get("/plans", response_model=PlanResponse)
+@router.get("/plans", response_model=PlanResponse)
 @start_as_current_span(TRACER)
 def get_plans(runner: WorkerDispatcher = Depends(_runner)):
     """Retrieve information about all available plans."""
     return PlanResponse(plans=runner.run(interface.get_plans))
 
 
-@app.get(
+@router.get(
     "/plans/{name}",
     response_model=PlanModel,
 )
@@ -136,14 +146,14 @@ def get_plan_by_name(name: str, runner: WorkerDispatcher = Depends(_runner)):
     return runner.run(interface.get_plan, name)
 
 
-@app.get("/devices", response_model=DeviceResponse)
+@router.get("/devices", response_model=DeviceResponse)
 @start_as_current_span(TRACER)
 def get_devices(runner: WorkerDispatcher = Depends(_runner)):
     """Retrieve information about all available devices."""
     return DeviceResponse(devices=runner.run(interface.get_devices))
 
 
-@app.get(
+@router.get(
     "/devices/{name}",
     response_model=DeviceModel,
 )
@@ -156,7 +166,7 @@ def get_device_by_name(name: str, runner: WorkerDispatcher = Depends(_runner)):
 example_task = Task(name="count", params={"detectors": ["x"]})
 
 
-@app.post(
+@router.post(
     "/tasks",
     response_model=TaskResponse,
     status_code=status.HTTP_201_CREATED,
@@ -190,7 +200,7 @@ def submit_task(
         ) from e
 
 
-@app.delete("/tasks/{task_id}", status_code=status.HTTP_200_OK)
+@router.delete("/tasks/{task_id}", status_code=status.HTTP_200_OK)
 @start_as_current_span(TRACER, "task_id")
 def delete_submitted_task(
     task_id: str,
@@ -207,7 +217,7 @@ def validate_task_status(v: str) -> TaskStatusEnum:
     return TaskStatusEnum(v_upper)
 
 
-@app.get("/tasks", response_model=TasksListResponse, status_code=status.HTTP_200_OK)
+@router.get("/tasks", response_model=TasksListResponse, status_code=status.HTTP_200_OK)
 @start_as_current_span(TRACER)
 def get_tasks(
     task_status: str | None = None,
@@ -234,7 +244,7 @@ def get_tasks(
     return TasksListResponse(tasks=tasks)
 
 
-@app.put(
+@router.put(
     "/worker/task",
     response_model=WorkerTask,
     responses={status.HTTP_409_CONFLICT: {"worker": "already active"}},
@@ -255,7 +265,7 @@ def set_active_task(
     return task
 
 
-@app.get(
+@router.get(
     "/tasks/{task_id}",
     response_model=TrackableTask,
 )
@@ -271,7 +281,7 @@ def get_task(
     return task
 
 
-@app.get("/worker/task")
+@router.get("/worker/task")
 @start_as_current_span(TRACER)
 def get_active_task(runner: WorkerDispatcher = Depends(_runner)) -> WorkerTask:
     active = runner.run(interface.get_active_task)
@@ -281,7 +291,7 @@ def get_active_task(runner: WorkerDispatcher = Depends(_runner)) -> WorkerTask:
         return WorkerTask(task_id=None)
 
 
-@app.get("/worker/state")
+@router.get("/worker/state")
 @start_as_current_span(TRACER)
 def get_state(runner: WorkerDispatcher = Depends(_runner)) -> WorkerState:
     """Get the State of the Worker"""
@@ -303,7 +313,7 @@ def get_state(runner: WorkerDispatcher = Depends(_runner)) -> WorkerState:
 }
 
 
-@app.put(
+@router.put(
     "/worker/state",
     status_code=status.HTTP_202_ACCEPTED,
     responses={
@@ -372,34 +382,39 @@ def start(config: ApplicationConfig):
         "%(asctime)s %(levelprefix)s %(client_addr)s"
         + " - '%(request_line)s' %(status_code)s"
     )
+    app = get_app()
+
     FastAPIInstrumentor().instrument_app(
         app,
         tracer_provider=get_tracer_provider(),
         http_capture_headers_server_request=[",*"],
         http_capture_headers_server_response=[",*"],
     )
     app.state.config = config
+
     uvicorn.run(app, host=config.api.host, port=config.api.port)
 
 
-@app.middleware("http")
-async def add_api_version_header(request: Request, call_next):
-    response = await call_next(request)
-    response.headers["X-API-Version"] = REST_API_VERSION
-    return response
+def add_api_version_header(app: FastAPI):
+    @app.middleware("http")
+    async def add_api_version_header(request: Request, call_next):
+        response = await call_next(request)
+        response.headers["X-API-Version"] = REST_API_VERSION
+        return response
 
 
-@app.middleware("http")
-async def inject_propagated_observability_context(
-    request: Request, call_next: Callable[[Request], Awaitable[Response]]
-) -> Response:
-    """Middleware to extract the any prorpagated observability context from the
-    HTTP headers and attatch it to the local one.
-    """
-    if CONTEXT_HEADER in request.headers:
-        ctx = get_global_textmap().extract(
-            {CONTEXT_HEADER: request.headers[CONTEXT_HEADER]}
-        )
-        attach(ctx)
-    response = await call_next(request)
-    return response
+def inject_propagated_observability_context(app: FastAPI):
+    @app.middleware("http")
+    async def inject_propagated_observability_context(
+        request: Request, call_next: Callable[[Request], Awaitable[Response]]
+    ) -> Response:
+        """Middleware to extract the any propagated observability context from the
+        HTTP headers and attach it to the local one.
+        """
+        if CONTEXT_HEADER in request.headers:
+            ctx = get_global_textmap().extract(
+                {CONTEXT_HEADER: request.headers[CONTEXT_HEADER]}
+            )
+            attach(ctx)
+        response = await call_next(request)
+        return response

src/blueapi/service/openapi.py

@@ -7,12 +7,13 @@
 from fastapi.openapi.utils import get_openapi
 from pyparsing import Any
 
-from blueapi.service.main import app
+from blueapi.service.main import get_app
 
 DOCS_SCHEMA_LOCATION = Path(__file__).parents[3] / "docs" / "reference" / "openapi.yaml"
 
 
 def generate_schema() -> Mapping[str, Any]:
+    app = get_app()
     return get_openapi(
         title=app.title,
         version=app.version,

tests/unit_tests/service/test_openapi.py

@@ -7,9 +7,13 @@
 from blueapi.service.openapi import DOCS_SCHEMA_LOCATION, generate_schema
 
 
-@mock.patch("blueapi.service.openapi.app")
-def test_generate_schema(mock_app: Mock) -> None:
-    from blueapi.service.main import app
+@mock.patch("blueapi.service.openapi.get_app")
+def test_generate_schema(mock_get_app: Mock) -> None:
+    mock_app = mock_get_app()
+
+    from blueapi.service.main import get_app
+
+    app = get_app()
 
     title = PropertyMock(return_value="title")
     version = PropertyMock(return_value=app.version)
@@ -23,8 +27,6 @@ def test_generate_schema(mock_app: Mock) -> None:
     type(mock_app).description = description
     type(mock_app).routes = routes
 
-    # from blueapi.service.openapi import generate_schema
-
     assert generate_schema() == {
         "openapi": openapi_version(),
         "info": {

tests/unit_tests/service/test_rest_api.py

@@ -25,11 +25,9 @@
 
 @pytest.fixture
 def client() -> Iterator[TestClient]:
-    with (
-        patch("blueapi.service.interface.worker"),
-    ):
+    with patch("blueapi.service.interface.worker"):
         main.setup_runner(use_subprocess=False)
-        yield TestClient(main.app)
+        yield TestClient(main.get_app())
         main.teardown_runner()