refactor(observability): restructure into service-owned packages

tests/unit/test_api_observability.py

@@ -0,0 +1,135 @@
+import httpx2
+import pytest
+from fastapi import FastAPI
+from fastapi.testclient import TestClient
+from prometheus_client import CONTENT_TYPE_LATEST
+
+from core.api.observability.metrics import ApiMetrics
+from core.api.observability.routes import create_observability_router
+from core.api.observability.stats import (
+    ApiRuntimeStats,
+    HttpWorkerStatsClient,
+    WorkerStatsUnavailable,
+)
+
+
+@pytest.mark.anyio
+async def test_http_worker_stats_client_success() -> None:
+    async def fake_handler(request: httpx2.Request) -> httpx2.Response:
+        assert request.url == "http://test-worker/internal/stats"
+        return httpx2.Response(
+            status_code=200,
+            json={
+                "pipeline": {
+                    "total_processed": 5,
+                    "total_dlq": 1,
+                    "in_flight_buffer": 2,
+                    "last_flush_at": "2026-09-22T12:00:00Z",
+                },
+                "breakdown": {
+                    "by_service_type": {"4G_DATA": 5},
+                    "by_radio_access_type": {"LTE_4G": 5},
+                    "dlq_by_reason": {"timeout": 1},
+                },
+            },
+        )
+
+    transport = httpx2.MockTransport(fake_handler)
+    client = HttpWorkerStatsClient(
+        url="http://test-worker/internal/stats",
+        timeout_seconds=2.0,
+    )
+    # Inject mock transport
+    client._client = httpx2.AsyncClient(transport=transport)
+
+    stats = await client.get_stats()
+    assert stats["pipeline"]["total_processed"] == 5
+    await client.close()
+
+
+@pytest.mark.anyio
+async def test_http_worker_stats_client_error() -> None:
+    async def failing_handler(request: httpx2.Request) -> httpx2.Response:
+        return httpx2.Response(status_code=500)
+
+    transport = httpx2.MockTransport(failing_handler)
+    client = HttpWorkerStatsClient(
+        url="http://test-worker/internal/stats",
+        timeout_seconds=2.0,
+    )
+    client._client = httpx2.AsyncClient(transport=transport)
+
+    with pytest.raises(WorkerStatsUnavailable) as exc_info:
+        await client.get_stats()
+
+    assert "Unable to retrieve worker stats" in str(exc_info.value)
+    await client.close()
+
+
+def test_api_observability_router_metrics() -> None:
+    metrics = ApiMetrics()
+    stats = ApiRuntimeStats()
+
+    class DummyWorkerStatsProvider:
+        async def get_stats(self) -> dict:
+            return {}
+
+        async def close(self) -> None:
+            pass
+
+    app = FastAPI()
+    router = create_observability_router(
+        metrics=metrics,
+        stats=stats,
+        worker_stats_provider=DummyWorkerStatsProvider(),
+    )
+    app.include_router(router)
+
+    client = TestClient(app)
+    response = client.get("/metrics")
+    assert response.status_code == 200
+    assert CONTENT_TYPE_LATEST in response.headers["content-type"]
+    assert "cdr_api_received_total" in response.text
+
+
+def test_api_observability_router_stats_aggregation() -> None:
+    metrics = ApiMetrics()
+    stats = ApiRuntimeStats()
+    stats.record_received()
+    stats.record_received()
+
+    class FakeProvider:
+        async def get_stats(self) -> dict:
+            return {
+                "pipeline": {
+                    "total_processed": 15,
+                    "total_dlq": 3,
+                    "in_flight_buffer": 0,
+                    "last_flush_at": "2026-09-22T10:00:00Z",
+                },
+                "breakdown": {
+                    "by_service_type": {"4G_DATA": 15},
+                    "by_radio_access_type": {"LTE_4G": 15},
+                    "dlq_by_reason": {},
+                },
+            }
+
+        async def close(self) -> None:
+            pass
+
+    app = FastAPI()
+    router = create_observability_router(
+        metrics=metrics,
+        stats=stats,
+        worker_stats_provider=FakeProvider(),
+    )
+    app.include_router(router)
+
+    client = TestClient(app)
+    response = client.get("/stats")
+    assert response.status_code == 200
+    body = response.json()
+    assert body["pipeline"]["total_received"] == 2
+    assert body["pipeline"]["total_processed"] == 15
+    assert body["pipeline"]["total_dlq"] == 3
+