Fix POI distance calculation reliability for remote/Celery execution

- Fix silent log loss: replace hardcoded "uvicorn.error" logger with __name__
  in osrm_client, otp_client, poi_distance_calculator, and poi_tasks (uvicorn
  logger has no handlers in Celery worker, so all errors were silently dropped)
- Add Celery retry: autoretry_for=(Exception,), max_retries=3, retry_backoff
- Add top-level exception handling in task with full traceback logging
- Fix upsert_distances: replace session.merge() (PK-based) with proper
  dialect-aware INSERT ON DUPLICATE KEY UPDATE / ON CONFLICT DO UPDATE
- Filter out listings with null/zero coordinates before routing
- Raise OSError when all routing engines fail with 0 results computed,
  distinguishing "nothing to compute" from "all engines unreachable"

rec/osrm_client.py

@@ -10,7 +10,7 @@ import aiohttp
 
 from config.routing_config import RoutingConfig
 
-logger = logging.getLogger("uvicorn.error")
+logger = logging.getLogger(__name__)
 
 
 @dataclass(frozen=True)

rec/otp_client.py

@@ -12,7 +12,7 @@ import aiohttp
 from config.routing_config import RoutingConfig
 from rec.utils import nextMonday
 
-logger = logging.getLogger("uvicorn.error")
+logger = logging.getLogger(__name__)
 
 # OTP 2.x GraphQL query for transit plan
 _PLAN_QUERY = """

repositories/poi_repository.py

@@ -52,9 +52,41 @@ class POIRepository:
             return True
 
     def upsert_distances(self, distances: list[POIDistance]) -> None:
+        """Insert or update POI distances, handling duplicate unique constraints."""
+        if not distances:
+            return
         with Session(self.engine) as session:
+            dialect = self.engine.dialect.name
             for dist in distances:
-                session.merge(dist)
+                values = {
+                    "listing_id": dist.listing_id,
+                    "listing_type": dist.listing_type,
+                    "poi_id": dist.poi_id,
+                    "travel_mode": dist.travel_mode,
+                    "duration_seconds": dist.duration_seconds,
+                    "distance_meters": dist.distance_meters,
+                    "computed_at": dist.computed_at,
+                }
+                if dialect == "mysql":
+                    from sqlalchemy.dialects.mysql import insert as mysql_insert
+                    stmt = mysql_insert(POIDistance).values(**values)
+                    stmt = stmt.on_duplicate_key_update(
+                        duration_seconds=stmt.inserted.duration_seconds,
+                        distance_meters=stmt.inserted.distance_meters,
+                        computed_at=stmt.inserted.computed_at,
+                    )
+                else:
+                    from sqlalchemy.dialects.sqlite import insert as sqlite_insert
+                    stmt = sqlite_insert(POIDistance).values(**values)
+                    stmt = stmt.on_conflict_do_update(
+                        index_elements=["listing_id", "listing_type", "poi_id", "travel_mode"],
+                        set_={
+                            "duration_seconds": stmt.excluded.duration_seconds,
+                            "distance_meters": stmt.excluded.distance_meters,
+                            "computed_at": stmt.excluded.computed_at,
+                        },
+                    )
+                session.execute(stmt)
             session.commit()
 
     def get_distances_for_listings(

services/poi_distance_calculator.py

@@ -15,7 +15,7 @@ from rec.otp_client import otp_transit_route
 from repositories.listing_repository import ListingRepository
 from repositories.poi_repository import POIRepository
 
-logger = logging.getLogger("uvicorn.error")
+logger = logging.getLogger(__name__)
 
 # Map travel mode names to OSRM profiles
 _OSRM_PROFILES = {
@@ -61,8 +61,25 @@ async def calculate_poi_distances(
         logger.info("No listings found for distance calculation")
         return 0
 
+    # Filter out listings without valid coordinates
+    valid_listings = [
+        l for l in listings
+        if l.latitude is not None and l.longitude is not None
+        and l.latitude != 0 and l.longitude != 0
+    ]
+    if len(valid_listings) < len(listings):
+        logger.warning(
+            f"Skipped {len(listings) - len(valid_listings)} listings "
+            f"with missing coordinates"
+        )
+    listings = valid_listings
+    if not listings:
+        logger.warning("No listings with valid coordinates")
+        return 0
+
     total_computed = 0
     total_modes = len(travel_modes)
+    modes_failed: list[str] = []
 
     for mode_idx, mode in enumerate(travel_modes):
         mode_upper = mode.upper()
@@ -105,6 +122,7 @@ async def calculate_poi_distances(
                 continue
         except (aiohttp.ClientError, OSError) as e:
             logger.error(f"Routing engine unreachable for {mode_upper}: {e}")
+            modes_failed.append(mode_upper)
             if on_progress:
                 on_progress(
                     total_computed, len(listings) * total_modes,
@@ -114,6 +132,13 @@ async def calculate_poi_distances(
 
         total_computed += computed
 
+    if modes_failed and total_computed == 0:
+        failed_str = ", ".join(modes_failed)
+        raise OSError(
+            f"All routing engines failed ({failed_str}). "
+            f"No distances computed for {len(listings)} listings."
+        )
+
     return total_computed
 
 

tasks/poi_tasks.py

@@ -11,7 +11,7 @@ from repositories.listing_repository import ListingRepository
 from repositories.poi_repository import POIRepository
 from services.poi_distance_calculator import calculate_poi_distances
 
-logger = logging.getLogger("uvicorn.error")
+logger = logging.getLogger(__name__)
 
 celery_logger = logging.getLogger("celery.task")
 if not celery_logger.handlers:
@@ -23,7 +23,13 @@ if not celery_logger.handlers:
     celery_logger.setLevel(logging.INFO)
 
 
-@app.task(bind=True)
+@app.task(
+    bind=True,
+    autoretry_for=(Exception,),
+    max_retries=3,
+    retry_backoff=True,
+    retry_backoff_max=300,
+)
 def calculate_poi_distances_task(
     self: Task,
     poi_id: int,
@@ -70,17 +76,23 @@ def calculate_poi_distances_task(
             "message": message,
         })
 
-    total = asyncio.run(
-        calculate_poi_distances(
-            listing_repo=listing_repo,
-            poi_repo=poi_repo,
-            poi=poi,
-            travel_modes=travel_modes,
-            listing_type=lt,
-            listing_ids=listing_ids,
-            on_progress=on_progress,
+    try:
+        total = asyncio.run(
+            calculate_poi_distances(
+                listing_repo=listing_repo,
+                poi_repo=poi_repo,
+                poi=poi,
+                travel_modes=travel_modes,
+                listing_type=lt,
+                listing_ids=listing_ids,
+                on_progress=on_progress,
+            )
         )
-    )
+    except Exception:
+        celery_logger.exception(
+            f"POI distance calculation failed: poi_id={poi_id}"
+        )
+        raise  # Let Celery's autoretry handle it
 
     celery_logger.info(f"POI distance calculation complete: {total} distances computed")