feat: add support of openmetrics (#144)

* feat: add openmetrics support & endpoint

* add support of named resources

* update docstrings

* generate docs

* add another test for http api

tests/ahriman/web/middlewares/test_metrics_handler.py

@@ -0,0 +1,59 @@
+import importlib
+import pytest
+import sys
+
+from aiohttp.web import HTTPNotFound
+from pytest_mock import MockerFixture
+from unittest.mock import AsyncMock
+
+import ahriman.web.middlewares.metrics_handler as metrics_handler
+
+
+async def test_metrics(mocker: MockerFixture) -> None:
+    """
+    must return metrics methods if library is available
+    """
+    metrics_mock = AsyncMock()
+    mocker.patch.object(metrics_handler, "aiohttp_openmetrics", metrics_mock)
+
+    await metrics_handler.metrics(42)
+    metrics_mock.metrics.assert_called_once_with(42)
+
+
+async def test_metrics_dummy(mocker: MockerFixture) -> None:
+    """
+    must raise HTTPNotFound if no module found
+    """
+    mocker.patch.object(metrics_handler, "aiohttp_openmetrics", None)
+    with pytest.raises(HTTPNotFound):
+        await metrics_handler.metrics(None)
+
+
+async def test_metrics_handler() -> None:
+    """
+    must return metrics handler if library is available
+    """
+    assert metrics_handler.metrics_handler() == metrics_handler.aiohttp_openmetrics.metrics_middleware
+
+
+async def test_metrics_handler_dummy(mocker: MockerFixture) -> None:
+    """
+    must return dummy handler if no module found
+    """
+    mocker.patch.object(metrics_handler, "aiohttp_openmetrics", None)
+    handler = metrics_handler.metrics_handler()
+
+    async def handle(result: int) -> int:
+        return result
+
+    assert await handler(42, handle) == 42
+
+
+def test_import_openmetrics_missing(mocker: MockerFixture) -> None:
+    """
+    must correctly process missing module
+    """
+    mocker.patch.dict(sys.modules, {"aiohttp_openmetrics": None})
+    importlib.reload(metrics_handler)
+
+    assert metrics_handler.aiohttp_openmetrics is None

tests/ahriman/web/schemas/test_any_schema.py

@@ -0,0 +1 @@
+# schema testing goes in view class tests

tests/ahriman/web/test_routes.py

@@ -3,7 +3,7 @@ from pathlib import Path
 
 from ahriman.core.configuration import Configuration
 from ahriman.core.utils import walk
-from ahriman.web.routes import _dynamic_routes, setup_routes
+from ahriman.web.routes import _dynamic_routes, _identifier, setup_routes
 
 
 def test_dynamic_routes(resource_path_root: Path, configuration: Configuration) -> None:
@@ -22,9 +22,19 @@ def test_dynamic_routes(resource_path_root: Path, configuration: Configuration)
     assert len(set(routes.values())) == len(expected_views)
 
 
+def test_identifier() -> None:
+    """
+    must correctly extract route identifiers
+    """
+    assert _identifier("/") == "_"
+    assert _identifier("/api/v1/status") == "_api_v1_status"
+    assert _identifier("/api/v1/packages/{package}") == "_api_v1_packages_:package"
+
+
 def test_setup_routes(application: Application, configuration: Configuration) -> None:
     """
     must generate non-empty list of routes
     """
+    application.router._named_resources = {}
     setup_routes(application, configuration)
     assert application.router.routes()

tests/ahriman/web/views/v1/status/test_view_v1_status_metrics.py

@@ -0,0 +1,50 @@
+import pytest
+
+from aiohttp.test_utils import TestClient
+from aiohttp.web import Response
+from pytest_mock import MockerFixture
+
+import ahriman.web.middlewares.metrics_handler as metrics_handler
+
+from ahriman.models.user_access import UserAccess
+from ahriman.web.views.v1.status.metrics import MetricsView
+
+
+async def test_get_permission() -> None:
+    """
+    must return correct permission for the request
+    """
+    for method in ("GET",):
+        request = pytest.helpers.request("", "", method)
+        assert await MetricsView.get_permission(request) == UserAccess.Unauthorized
+
+
+def test_routes() -> None:
+    """
+    must return correct routes
+    """
+    assert MetricsView.ROUTES == ["/api/v1/metrics"]
+
+
+async def test_get(client: TestClient, mocker: MockerFixture) -> None:
+    """
+    must return service metrics
+    """
+    metrics_mock = mocker.patch("ahriman.web.views.v1.status.metrics.metrics", return_value=Response())
+
+    response = await client.get("/api/v1/metrics")
+    assert response.ok
+    # there is no response validation here, because it is free text, so we check call instead
+    metrics_mock.assert_called_once_with(pytest.helpers.anyvar(int))
+
+
+async def test_get_not_found(client: TestClient, mocker: MockerFixture) -> None:
+    """
+    must return 404 error if no module found
+    """
+    mocker.patch.object(metrics_handler, "aiohttp_openmetrics", None)
+    response_schema = pytest.helpers.schema_response(MetricsView.get, code=404)
+
+    response = await client.get("/api/v1/metrics")
+    assert response.status == 404
+    assert not response_schema.validate(await response.json())