Fix metric imports: use module-level access instead of name imports

Type-annotated metric variables (e.g. `geojson_cache_operations: Counter`)
don't exist as importable names until init_metrics() runs.  Switch all
`from api.metrics import <metric>` to `import api.metrics as m` and
access instruments as attributes at runtime to avoid ImportError.

api/app.py

@@ -39,7 +39,8 @@ from services.listing_cache import (
 from repositories.poi_repository import POIRepository
 from repositories.user_repository import UserRepository
 from opentelemetry.instrumentation.fastapi import FastAPIInstrumentor
-from api.metrics import init_metrics, get_metrics_asgi_app, geojson_cache_operations
+from api.metrics import init_metrics, get_metrics_asgi_app
+import api.metrics as app_metrics
 from logging_config import configure_logging
 
 
@@ -324,10 +325,10 @@ async def stream_listing_geojson(
 
     cached_count = get_cached_count(query_parameters)
     if cached_count is not None and cached_count > 0 and not include_poi_distances:
-        geojson_cache_operations.add(1, {"result": "hit"})
+        app_metrics.geojson_cache_operations.add(1, {"result": "hit"})
         generator = _stream_from_cache(query_parameters, batch_size, limit)
     else:
-        geojson_cache_operations.add(1, {"result": "miss"})
+        app_metrics.geojson_cache_operations.add(1, {"result": "miss"})
         generator = _stream_from_db(
             query_parameters, batch_size, limit, poi_distances_lookup,
             skip_cache=include_poi_distances,

celery_app.py

@@ -47,9 +47,9 @@ def _start_metrics_server(**kwargs: object) -> None:
 
 @task_prerun.connect
 def _on_task_prerun(task_id: str, task: object, **kwargs: object) -> None:
-    from api.metrics import celery_tasks_active
+    import api.metrics as m
     task_name = getattr(task, "name", "unknown")
-    celery_tasks_active.add(1, {"task_name": task_name})
+    m.celery_tasks_active.add(1, {"task_name": task_name})
     _task_start_times[task_id] = time.monotonic()
 
 
@@ -57,16 +57,16 @@ def _on_task_prerun(task_id: str, task: object, **kwargs: object) -> None:
 def _on_task_postrun(
     task_id: str, task: object, state: str | None = None, **kwargs: object
 ) -> None:
-    from api.metrics import celery_tasks_total, celery_task_duration_seconds, celery_tasks_active
+    import api.metrics as m
     task_name = getattr(task, "name", "unknown")
     status = state or "UNKNOWN"
 
-    celery_tasks_active.add(-1, {"task_name": task_name})
-    celery_tasks_total.add(1, {"task_name": task_name, "status": status})
+    m.celery_tasks_active.add(-1, {"task_name": task_name})
+    m.celery_tasks_total.add(1, {"task_name": task_name, "status": status})
 
     start = _task_start_times.pop(task_id, None)
     if start is not None:
-        celery_task_duration_seconds.record(
+        m.celery_task_duration_seconds.record(
             time.monotonic() - start, {"task_name": task_name}
         )
 

listing_processor.py

@@ -326,10 +326,10 @@ class DetectFloorplanStep(Step):
 
         # Record OCR metrics
         try:
-            from api.metrics import ocr_attempts, ocr_successes
-            ocr_attempts.add(1)
+            import api.metrics as m
+            m.ocr_attempts.add(1)
             if max_sqm > 0:
-                ocr_successes.add(1)
+                m.ocr_successes.add(1)
         except Exception:
             pass  # Metrics not initialised
 

rec/throttle_detector.py

@@ -159,8 +159,8 @@ def reset_throttle_metrics() -> None:
 def _increment_throttle_metric(event_type: str) -> None:
     """Safely increment the OTel throttle counter if metrics are initialised."""
     try:
-        from api.metrics import throttle_events_total
-        throttle_events_total.add(1, {"type": event_type})
+        import api.metrics as m
+        m.throttle_events_total.add(1, {"type": event_type})
     except Exception:
         pass  # Metrics not yet initialised (e.g. during tests)
 

tasks/listing_tasks.py

@@ -568,20 +568,13 @@ async def _dump_listings_full_inner(
     celery_logger.info("=" * 60)
 
     # Record scrape metrics
-    from api.metrics import (
-        scrape_listings_found,
-        scrape_listings_processed,
-        scrape_listings_failed,
-        scrape_duration_seconds,
-        scrape_pages_fetched,
-        scrape_subqueries_total as scrape_subqueries_metric,
-    )
-    scrape_listings_found.add(state.ids_collected)
-    scrape_listings_processed.add(state.processed_count)
-    scrape_listings_failed.add(state.failed_count)
-    scrape_duration_seconds.record(elapsed)
-    scrape_pages_fetched.add(state.total_pages_fetched)
-    scrape_subqueries_metric.add(state.completed_subqueries)
+    import api.metrics as m
+    m.scrape_listings_found.add(state.ids_collected)
+    m.scrape_listings_processed.add(state.processed_count)
+    m.scrape_listings_failed.add(state.failed_count)
+    m.scrape_duration_seconds.record(elapsed)
+    m.scrape_pages_fetched.add(state.total_pages_fetched)
+    m.scrape_subqueries_total.add(state.completed_subqueries)
 
     invalidate_cache()