chore: improve image worker logging

apps/api/management/commands/run_image_tasks.py

@@ -4,6 +4,7 @@ import uuid
 from django.conf import settings
 from django.core.management.base import BaseCommand
 
+from apps.api.models import ImageGenerationTask
 from apps.api.image_tasks import reap_stale_image_tasks, run_one_image_task
 
 
@@ -56,7 +57,7 @@ class Command(BaseCommand):
 
             task = run_one_image_task(worker_id=worker_id)
             if task is not None:
-                self.stdout.write(f"task={task.task_id} status={task.status}")
+                self.stdout.write(format_task_log_line(task, started_at=now))
                 if once:
                     return
                 continue
@@ -64,3 +65,18 @@ class Command(BaseCommand):
             if once:
                 return
             time.sleep(sleep_seconds)
+
+
+def format_task_log_line(task: ImageGenerationTask, *, started_at: float) -> str:
+    duration_ms = max(0, int((time.monotonic() - started_at) * 1000))
+    alias = str((task.request_payload or {}).get("model") or "")
+    fields = {
+        "event": "image_task_processed",
+        "task_id": str(task.task_id),
+        "status": task.status,
+        "alias": alias,
+        "duration_ms": str(duration_ms),
+    }
+    if task.status in {ImageGenerationTask.Status.FAILED, ImageGenerationTask.Status.EXPIRED}:
+        fields["error_code"] = task.error_code or "upstream_error"
+    return " ".join(f"{key}={value}" for key, value in fields.items())