Retry interrupted thematic WCS tiles

2026-07-16 04:46:13 +02:00
parent 6a7fa57463
commit 791548e332
2 changed files with 87 additions and 24 deletions
@@ -6,6 +6,7 @@ import math
 import time
 from dataclasses import dataclass
 from datetime import UTC, datetime
+from http.client import HTTPException
 from pathlib import Path
 from typing import Any, Callable
 from urllib.error import HTTPError, URLError
@@ -55,6 +56,8 @@ class ThematicRasterAcquisitionService:
    NODATA = -9999.0
    WCS_TILE_SIDE_M = 10_000.0
    WCS_REQUEST_INTERVAL_SECONDS = 0.5
+    WCS_FETCH_ATTEMPTS = 3
+    WCS_RETRY_DELAY_SECONDS = 1.0
    ATTRIBUTION = "Bron: Departement Omgeving, MercatorNet"
    LICENSE_NOTE = "Publieke GDI-Vlaanderen bron; bronvermelding en productspecifieke gebruiksvoorwaarden blijven van toepassing."

@@ -305,30 +308,38 @@ class ThematicRasterAcquisitionService:
    def _fetch(request_url: str, settings: Settings, opener: Callable[..., Any] | None = None) -> tuple[bytes, str]:
        request = Request(request_url, headers={"Accept": "image/tiff,*/*", "User-Agent": "GeoIntel/0.1 bounded-thematic-raster"})
        max_bytes = settings.thematic_raster_max_response_mb * 1024 * 1024
-        try:
-            with (opener or urlopen)(request, timeout=settings.thematic_raster_timeout_seconds) as response:
-                content_type = str(response.headers.get("Content-Type", ""))
-                content_length = response.headers.get("Content-Length")
-                if content_length and int(content_length) > max_bytes:
-                    raise AppError(code="THEMATIC_RASTER_RESPONSE_TOO_LARGE", message="Official raster response exceeds the configured size limit", status_code=502)
-                content = response.read(max_bytes + 1)
-        except AppError:
-            raise
-        except HTTPError as exc:
-            preview = exc.read(300).decode("utf-8", errors="replace")
-            raise AppError(
-                code="THEMATIC_RASTER_PROVIDER_UNAVAILABLE",
-                message="The official MercatorNet WCS could not complete the bounded request",
-                details={"reason": str(exc), "provider_status_code": int(exc.code), "response_preview": preview},
-                status_code=502,
-            ) from exc
-        except (URLError, TimeoutError, OSError) as exc:
-            raise AppError(
-                code="THEMATIC_RASTER_PROVIDER_UNAVAILABLE",
-                message="The official MercatorNet WCS could not complete the bounded request",
-                details={"reason": str(exc)},
-                status_code=502,
-            ) from exc
+        for attempt in range(1, ThematicRasterAcquisitionService.WCS_FETCH_ATTEMPTS + 1):
+            try:
+                with (opener or urlopen)(request, timeout=settings.thematic_raster_timeout_seconds) as response:
+                    content_type = str(response.headers.get("Content-Type", ""))
+                    content_length = response.headers.get("Content-Length")
+                    if content_length and int(content_length) > max_bytes:
+                        raise AppError(code="THEMATIC_RASTER_RESPONSE_TOO_LARGE", message="Official raster response exceeds the configured size limit", status_code=502)
+                    content = response.read(max_bytes + 1)
+                break
+            except AppError:
+                raise
+            except HTTPError as exc:
+                preview = exc.read(300).decode("utf-8", errors="replace")
+                if attempt < ThematicRasterAcquisitionService.WCS_FETCH_ATTEMPTS and int(exc.code) in {429, 500, 502, 503, 504}:
+                    time.sleep(ThematicRasterAcquisitionService.WCS_RETRY_DELAY_SECONDS * attempt)
+                    continue
+                raise AppError(
+                    code="THEMATIC_RASTER_PROVIDER_UNAVAILABLE",
+                    message="The official MercatorNet WCS could not complete the bounded request",
+                    details={"reason": str(exc), "provider_status_code": int(exc.code), "response_preview": preview, "attempts": attempt},
+                    status_code=502,
+                ) from exc
+            except (URLError, TimeoutError, OSError, HTTPException) as exc:
+                if attempt < ThematicRasterAcquisitionService.WCS_FETCH_ATTEMPTS:
+                    time.sleep(ThematicRasterAcquisitionService.WCS_RETRY_DELAY_SECONDS * attempt)
+                    continue
+                raise AppError(
+                    code="THEMATIC_RASTER_PROVIDER_UNAVAILABLE",
+                    message="The official MercatorNet WCS could not complete the bounded request",
+                    details={"reason": str(exc), "attempts": attempt},
+                    status_code=502,
+                ) from exc
        if len(content) > max_bytes:
            raise AppError(code="THEMATIC_RASTER_RESPONSE_TOO_LARGE", message="Official raster response exceeds the configured size limit", status_code=502)
        if not content.startswith((b"II*\x00", b"MM\x00*")):