fix: reduce memory usage for monthly ZIP archive flow

Replace generated archive download response with FileResponse streaming so ZIP files are not fully loaded into process memory.

Move monthly archive task output to a temporary file and upload that file to storage, and write invoice attachments into ZIP archives in chunks.

Add Celery memory guard settings, a memory-aware base task hook, and periodic /tmp cleanup for prefixed archive files older than one day.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

README.md

@@ -7,7 +7,7 @@ Nakon što je gitea webhook i testirana skripta za automatsko povlačenje promje
 ```bash
 cd /opt/erp/app
 git fetch origin
-git reset --hard origin/main
+git reset --hard origin/main ili git pull --ff-only origin main
 
 # rebuild backend + worker + beat + frontend
 docker compose -f docker-compose.yml -f docker-compose.prod.yml build backend worker beat frontend

backend/core/celery.py

@@ -1,7 +1,12 @@
 # backend/core/celery.py
 
 import os
+import gc
+import logging
 from celery import Celery
+from celery import Task
+
+logger = logging.getLogger(__name__)
 
 # Postavi Django settings modul
 os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'core.settings')
@@ -11,5 +16,42 @@ app = Celery('core')
 # Koristi konfiguraciju iz settings.py s prefiksom 'CELERY_'
 app.config_from_object('django.conf:settings', namespace='CELERY')
 
+
+def _rss_memory_mb():
+    try:
+        import resource
+
+        usage_kb = resource.getrusage(resource.RUSAGE_SELF).ru_maxrss
+        # Na Linuxu je ru_maxrss u KiB.
+        return round(float(usage_kb) / 1024.0, 2)
+    except (ImportError, AttributeError, OSError, ValueError):
+        return None
+
+
+class MemoryAwareTask(Task):
+    abstract = True
+
+    def __call__(self, *args, **kwargs):
+        gc.collect()
+        return super().__call__(*args, **kwargs)
+
+    def after_return(self, status, retval, task_id, args, kwargs, einfo):
+        memory_before_gc = _rss_memory_mb()
+        gc.collect()
+        memory_after_gc = _rss_memory_mb()
+        if memory_before_gc is not None and memory_after_gc is not None:
+            logger.info(
+                "Task %s (%s) status=%s RSS prije/poslije GC: %.2fMB -> %.2fMB",
+                self.name,
+                task_id,
+                status,
+                memory_before_gc,
+                memory_after_gc,
+            )
+        return super().after_return(status, retval, task_id, args, kwargs, einfo)
+
+
+app.Task = MemoryAwareTask
+
 # Automatski pronalazi taskove u svim 'modules.*'
 app.autodiscover_tasks()

backend/core/settings/base.py

@@ -154,6 +154,11 @@ REDIS_URL = os.environ.get('REDIS_URL', 'redis://localhost:6379/0')
 
 CELERY_BROKER_URL = REDIS_URL
 CELERY_RESULT_BACKEND = REDIS_URL
+CELERY_WORKER_PREFETCH_MULTIPLIER = int(os.environ.get('CELERY_WORKER_PREFETCH_MULTIPLIER', '1'))
+CELERY_WORKER_MAX_TASKS_PER_CHILD = int(os.environ.get('CELERY_WORKER_MAX_TASKS_PER_CHILD', '20'))
+CELERY_WORKER_MAX_MEMORY_PER_CHILD = int(os.environ.get('CELERY_WORKER_MAX_MEMORY_PER_CHILD', '350000'))
+CELERY_TASK_ACKS_LATE = True
+CELERY_TASK_REJECT_ON_WORKER_LOST = True
 
 # Ako želiš koristiti Redis kao brzi cache sustav unutar Djanga (izvrsno za ERP performanse)
 # Za ovo ti je potreban paket 'django-redis' u requirements.txt
@@ -171,10 +176,18 @@ CACHES = {
 CELERY_ACCEPT_CONTENT = ['json']
 CELERY_TASK_SERIALIZER = 'json'
 CELERY_BEAT_SCHEDULE = {
+    'cleanup-expired-generated-archives-hourly': {
+        'task': 'modules.fleet.tasks.cleanup_expired_generated_archives_task',
+        'schedule': crontab(minute=5),
+    },
     'cleanup-expired-generated-pdfs-hourly': {
         'task': 'modules.fleet.tasks.cleanup_expired_generated_pdfs_task',
         'schedule': crontab(minute=0),
     },
+    'cleanup-app-tmp-daily': {
+        'task': 'modules.fleet.tasks.cleanup_tmp_files_task',
+        'schedule': crontab(hour=3, minute=15),
+    },
     'notify-upcoming-tasks-daily': {
         'task': 'modules.task_management.tasks.notify_upcoming_tasks',
         'schedule': crontab(hour=8, minute=0),
@@ -190,6 +203,13 @@ STATIC_URL = '/static/'
 # (Opcionalno, ali preporučeno za ERP) Ako koristiš i medije (dokumente)
 MEDIA_URL = '/media/'
 MEDIA_ROOT = BASE_DIR / 'media'
+APP_TMP_CLEANUP_DIR = os.environ.get('APP_TMP_CLEANUP_DIR', '/tmp')
+APP_TMP_CLEANUP_MAX_AGE_HOURS = int(os.environ.get('APP_TMP_CLEANUP_MAX_AGE_HOURS', '24'))
+APP_TMP_CLEANUP_PREFIXES = [
+    prefix.strip()
+    for prefix in os.environ.get('APP_TMP_CLEANUP_PREFIXES', 'erp-fleet-archive-').split(',')
+    if prefix.strip()
+]
 
 
 # ==============================================================================

backend/modules/fleet/models.py

@@ -2,10 +2,12 @@ import uuid
 import re
 from datetime import time
 from django.db import models
+from django.db.models.signals import post_save, pre_delete
 from django.conf import settings
 from django.core.exceptions import ValidationError
 from django.utils.translation import gettext_lazy as _
 from django.utils import timezone
+from django.dispatch import receiver
 from core.base_models import BaseModel
 from decimal import Decimal
 
@@ -142,6 +144,67 @@ class VehicleServiceAttachment(BaseModel):
     def __str__(self):
         return f"Attachment {self.pk} for {self.service_record} ({self.file.name if self.file else 'no-file'})"
 
+
+def _service_record_work_order_id(instance):
+    if isinstance(instance, VehicleServiceRecord):
+        task = getattr(instance, 'task', None)
+        if task and getattr(task, 'work_order_id', None):
+            return task.work_order_id
+        if getattr(instance, 'task_id', None):
+            return VehicleServiceRecord.objects.filter(pk=instance.pk).values_list('task__work_order_id', flat=True).first()
+        return None
+
+    service_record = getattr(instance, 'service_record', None)
+    if service_record and getattr(service_record, 'task', None) and getattr(service_record.task, 'work_order_id', None):
+        return service_record.task.work_order_id
+
+    service_record_id = getattr(instance, 'service_record_id', None)
+    if not service_record_id:
+        return None
+    return VehicleServiceRecord.objects.filter(pk=service_record_id).values_list('task__work_order_id', flat=True).first()
+
+
+def _invalidate_service_records_pdf_cache(work_order_id):
+    if not work_order_id:
+        return
+
+    cached_pdfs = GeneratedWorkOrderPdf.objects.filter(
+        is_active=True,
+        work_order_id=work_order_id,
+        pdf_type='service_records',
+    )
+    for cached in cached_pdfs:
+        file_name = getattr(cached.file, 'name', '')
+        if file_name:
+            try:
+                if cached.file.storage.exists(file_name):
+                    cached.file.delete(save=False)
+            except (FileNotFoundError, OSError, ValueError):
+                pass
+        cached.file = None
+        cached.is_active = False
+        cached.status = 'failed'
+        cached.error_message = 'PDF cache invalidiran zbog promjene servisnih zapisa.'
+        cached.save(update_fields=['file', 'is_active', 'status', 'error_message', 'updated_at'])
+
+
+@receiver(post_save, sender='fleet.VehicleServiceRecord')
+@receiver(pre_delete, sender='fleet.VehicleServiceRecord')
+def _invalidate_service_records_pdf_for_service_record(sender, instance, **kwargs):
+    _invalidate_service_records_pdf_cache(_service_record_work_order_id(instance))
+
+
+@receiver(post_save, sender='fleet.VehicleServicePhoto')
+@receiver(pre_delete, sender='fleet.VehicleServicePhoto')
+def _invalidate_service_records_pdf_for_service_photo(sender, instance, **kwargs):
+    _invalidate_service_records_pdf_cache(_service_record_work_order_id(instance))
+
+
+@receiver(post_save, sender='fleet.VehicleServiceAttachment')
+@receiver(pre_delete, sender='fleet.VehicleServiceAttachment')
+def _invalidate_service_records_pdf_for_service_attachment(sender, instance, **kwargs):
+    _invalidate_service_records_pdf_cache(_service_record_work_order_id(instance))
+
 class Vehicle(BaseModel):
     ASSET_TYPE_CHOICES = [
         ('vehicle', _("Vozilo")),

backend/modules/fleet/tasks.py

@@ -5,6 +5,7 @@ from django.core.mail import EmailMessage
 from django.conf import settings
 from django.utils import timezone
 from django.core.files.base import ContentFile
+from django.core.files import File
 import logging
 from io import BytesIO
 from io import StringIO
@@ -13,6 +14,9 @@ import base64
 import re
 import csv
 import mimetypes
+import os
+import tempfile
+import zipfile
 from decimal import Decimal, InvalidOperation
 from smtplib import SMTPSenderRefused
 from datetime import timedelta
@@ -838,10 +842,9 @@ def process_work_order_invoice_ocr(invoice_id):
 @shared_task
 def build_monthly_archive_cached_task(generated_archive_id):
     from .models import GeneratedFleetArchive
-    from .services import NotificationService
     from .views import (
-        _build_monthly_service_tasks_archive_content,
-        _build_monthly_work_orders_archive_content,
+        _write_monthly_service_tasks_archive_entries,
+        _write_monthly_work_orders_archive_entries,
         _notify_monthly_archive_request,
     )
 
@@ -854,25 +857,39 @@ def build_monthly_archive_cached_task(generated_archive_id):
     if generated is None:
         return {"status": "failed", "error": "Generated archive record not found"}
 
+    tmp_dir = str(getattr(settings, 'APP_TMP_CLEANUP_DIR', '/tmp'))
+    with tempfile.NamedTemporaryFile(
+        mode='w+b',
+        delete=False,
+        dir=tmp_dir if os.path.isdir(tmp_dir) else None,
+        prefix='erp-fleet-archive-',
+        suffix='.zip',
+    ) as temp_zip:
+        temp_zip_path = temp_zip.name
     try:
+        with zipfile.ZipFile(temp_zip_path, mode='w', compression=zipfile.ZIP_DEFLATED) as archive:
             if generated.archive_type == 'service_tasks':
-            archive_content = _build_monthly_service_tasks_archive_content(
+                entries_written = _write_monthly_service_tasks_archive_entries(
+                    archive,
                     user=generated.requested_by,
                     year=generated.year,
                     month=generated.month,
                 )
             else:
-            archive_content = _build_monthly_work_orders_archive_content(
+                entries_written = _write_monthly_work_orders_archive_entries(
+                    archive,
                     user=generated.requested_by,
                     year=generated.year,
                     month=generated.month,
                 )
-
-        if not archive_content:
+        if entries_written == 0:
             raise ValueError('ZIP arhiva je prazna.')
 
+        if os.path.getsize(temp_zip_path) <= 0:
+            raise ValueError('ZIP arhiva je prazna.')
         filename = generated.filename or f"{generated.archive_type}-{generated.year}-{generated.month}.zip"
-        generated.file.save(filename, ContentFile(archive_content), save=False)
+        with open(temp_zip_path, 'rb') as temp_file:
+            generated.file.save(filename, File(temp_file), save=False)
         generated.status = 'ready'
         generated.error_message = ''
         generated.save(update_fields=['file', 'status', 'error_message', 'updated_at'])
@@ -902,6 +919,12 @@ def build_monthly_archive_cached_task(generated_archive_id):
             )
         logger.exception("Greška kod build_monthly_archive_cached_task: %s", exc)
         return {"status": "failed", "error": str(exc)}
+    finally:
+        try:
+            if os.path.exists(temp_zip_path):
+                os.remove(temp_zip_path)
+        except OSError:
+            logger.warning("Ne mogu obrisati privremenu ZIP datoteku: %s", temp_zip_path)
 
 
 @shared_task
@@ -944,6 +967,46 @@ def cleanup_expired_generated_pdfs_task():
     return {"deleted": deleted}
 
 
+@shared_task
+def cleanup_tmp_files_task():
+    tmp_dir = str(getattr(settings, 'APP_TMP_CLEANUP_DIR', '/tmp'))
+    max_age_hours = int(getattr(settings, 'APP_TMP_CLEANUP_MAX_AGE_HOURS', 24))
+    prefixes = tuple(getattr(settings, 'APP_TMP_CLEANUP_PREFIXES', ['erp-fleet-archive-']))
+
+    if max_age_hours <= 0:
+        raise ValueError('APP_TMP_CLEANUP_MAX_AGE_HOURS mora biti > 0.')
+    if not prefixes:
+        raise ValueError('APP_TMP_CLEANUP_PREFIXES ne smije biti prazan.')
+    if not os.path.isdir(tmp_dir):
+        return {'deleted': 0, 'tmp_dir': tmp_dir, 'reason': 'tmp-dir-not-found'}
+
+    now = timezone.now().timestamp()
+    cutoff = now - (max_age_hours * 3600)
+    deleted = 0
+
+    for name in os.listdir(tmp_dir):
+        if not any(name.startswith(prefix) for prefix in prefixes):
+            continue
+        full_path = os.path.join(tmp_dir, name)
+        try:
+            stat_info = os.stat(full_path)
+        except FileNotFoundError:
+            continue
+        if stat_info.st_mtime > cutoff:
+            continue
+        if os.path.isdir(full_path):
+            try:
+                os.rmdir(full_path)
+            except OSError:
+                logger.warning("Preskačem %s: direktorij nije prazan ili je nedostupan.", full_path)
+                continue
+        else:
+            os.remove(full_path)
+        deleted += 1
+
+    return {'deleted': deleted, 'tmp_dir': tmp_dir, 'max_age_hours': max_age_hours}
+
+
 @shared_task
 def build_work_order_pdf_cached_task(generated_pdf_id):
     from .views import _build_work_order_pdf, _build_work_order_service_records_pdf

backend/modules/fleet/tests/test_work_order_images_endpoint.py

@@ -26,7 +26,12 @@ from modules.fleet.models import (
 )
 from modules.task_management.models import Task, TaskWorkHoursTable
 from modules.fleet.tasks import build_monthly_archive_cached_task
-from modules.fleet.views import _build_monthly_servicer_report_rows, _calculate_daily_quantity_from_hours
+from modules.fleet.views import (
+    _build_monthly_servicer_report_rows,
+    _calculate_daily_quantity_from_hours,
+    _compress_image_for_docx,
+    _work_order_related_tasks_queryset,
+)
 
 
 def create_test_image(filename='test.jpg', size=(40, 40), color='red'):
@@ -236,6 +241,58 @@ class WorkOrderImagesEndpointTests(TestCase):
         self.assertIn('additional_costs_table', payload)
         self.assertEqual(payload['additional_costs_table']['total_for_payout'], '5.00')
 
+    def test_compress_image_for_docx_keeps_standard_phone_photos(self):
+        file = BytesIO()
+        Image.new('RGB', (4000, 3000), color='blue').save(file, format='JPEG', quality=85)
+        file.seek(0)
+        uploaded = SimpleUploadedFile('phone-12mp.jpg', file.getvalue(), content_type='image/jpeg')
+
+        result = _compress_image_for_docx(uploaded)
+
+        self.assertIsNotNone(result)
+        self.assertGreater(len(result.getvalue()), 0)
+
+    def test_compress_image_for_docx_handles_exif_orientation(self):
+        exif = Image.Exif()
+        exif[0x0112] = 6
+
+        file = BytesIO()
+        Image.new('RGB', (3000, 2000), color='green').save(file, format='JPEG', quality=85, exif=exif.tobytes())
+        file.seek(0)
+        uploaded = SimpleUploadedFile('rotated-phone.jpg', file.getvalue(), content_type='image/jpeg')
+
+        result = _compress_image_for_docx(uploaded)
+
+        self.assertIsNotNone(result)
+        self.assertGreater(len(result.getvalue()), 0)
+
+    def test_work_order_related_tasks_queryset_excludes_other_work_orders_for_same_vehicle(self):
+        other_work_order = WorkOrder.objects.create(
+            vehicle=self.vehicle,
+            creator=self.user,
+            display_code='MT160726',
+            purpose='kontrola',
+        )
+        other_task = Task.objects.create(
+            title='Drugi nalog isti stroj',
+            assigned_to=self.user,
+            vehicle=self.vehicle,
+            work_order=other_work_order,
+            scheduled_date=date(2033, 12, 25),
+        )
+        VehicleServiceRecord.objects.create(
+            vehicle=self.vehicle,
+            task=other_task,
+            performed_by=self.user,
+            description='Ne smije se pojaviti u prvom nalogu.',
+            service_title='Krivi nalog',
+        )
+
+        resolved_ids = list(_work_order_related_tasks_queryset(self.work_order).values_list('id', flat=True))
+
+        self.assertIn(self.task.pk, resolved_ids)
+        self.assertNotIn(other_task.pk, resolved_ids)
+
     def test_invoice_upload_immediately_appears_in_additional_costs_table(self):
         create_response = self.client.post(
             reverse('work-order-invoice-list'),
@@ -298,6 +355,52 @@ class WorkOrderImagesEndpointTests(TestCase):
         self.assertFalse(cached.is_active)
         self.assertEqual(cached.status, 'failed')
 
+    def test_service_record_delete_invalidates_service_records_pdf_cache(self):
+        cached = GeneratedWorkOrderPdf.objects.create(
+            work_order=self.work_order,
+            requested_by=self.user,
+            pdf_type='service_records',
+            status='ready',
+            filename='MT150726.work-order-service-records.pdf',
+            expires_at=timezone.now() + timedelta(hours=1),
+        )
+        cached.file.save(
+            'MT150726.work-order-service-records.pdf',
+            ContentFile(b'%PDF-1.4 cached service records'),
+            save=True,
+        )
+
+        VehicleServiceRecord.objects.filter(pk=self.service_record.pk).delete()
+
+        cached.refresh_from_db()
+        self.assertFalse(cached.is_active)
+        self.assertEqual(cached.status, 'failed')
+        self.assertFalse(cached.file.name)
+
+    def test_service_records_pdf_rebuilds_when_cached_file_is_missing(self):
+        cached = GeneratedWorkOrderPdf.objects.create(
+            work_order=self.work_order,
+            requested_by=self.user,
+            pdf_type='service_records',
+            status='ready',
+            filename='MT150726.work-order-service-records.pdf',
+            expires_at=timezone.now() + timedelta(hours=1),
+        )
+        cached.file.save(
+            'MT150726.work-order-service-records.pdf',
+            ContentFile(b'%PDF-1.4 cached service records'),
+            save=True,
+        )
+        cached.file.storage.delete(cached.file.name)
+
+        response = self.client.get(f"/api/fleet/work-orders/{self.work_order.pk}/service-records-pdf/")
+        self.assertEqual(response.status_code, 200, response.content)
+        self.assertEqual(response['Content-Type'], 'application/pdf')
+
+        cached.refresh_from_db()
+        self.assertFalse(cached.is_active)
+        self.assertEqual(cached.status, 'failed')
+
     def test_service_records_docx_contains_embedded_service_photos(self):
         VehicleServicePhoto.objects.create(
             service_record=self.service_record,

backend/modules/fleet/views.py

@@ -14,7 +14,7 @@ from pathlib import Path
 from decimal import Decimal, InvalidOperation
 from django.contrib.auth import get_user_model
 
-from PIL import Image, UnidentifiedImageError
+from PIL import Image, ImageOps, UnidentifiedImageError
 from django.conf import settings
 from django.core.mail import EmailMessage
 from django.core.exceptions import ValidationError as DjangoValidationError
@@ -155,6 +155,7 @@ def _work_order_related_tasks_queryset(work_order):
             vehicle_id=work_order.vehicle_id,
             task_id__isnull=False,
             task__is_active=True,
+            task__work_order=work_order,
         ).values_list('task_id', flat=True)
     )
     task_ids = list({*direct_task_ids, *inferred_task_ids})
@@ -463,24 +464,32 @@ def _resolve_service_report_tasks(work_order, task_id):
     return [selected_task], selected_task
 
 
-def _compress_image_for_pdf(image_field, max_width=1280, quality=75):
+_COMPRESS_IMAGE_MAX_MEGAPIXELS = 30  # preskači tek vrlo velike slike (>30 MP); standardni telefoni 12–20 MP ostaju uključeni
+
+
+def _compress_image_for_pdf(image_field, max_width=800, quality=75):
     """
     Otvori image_field (Django FileField), kompresiraj na max_width JPEG u memoriji,
     vrati ImageReader spreman za reportlab. Vraća None ako slika nije dostupna.
+
+    BILINEAR umjesto LANCZOS: višestruko brže za velike slike (izbjeći Gunicorn timeout).
+    Megapixel guard čita samo header i preskače slike > 8 MP bez dekodiranja piksela.
+    except BaseException hvata i SystemExit koji Gunicorn diže na SIGABRT (worker timeout).
     """
     try:
         image_field.open('rb')
-        with Image.open(image_field) as src:
-            img = src.convert('RGB')
-            if img.width > max_width:
-                ratio = max_width / float(img.width)
-                new_h = max(1, int(img.height * ratio))
-                img = img.resize((max_width, new_h), Image.LANCZOS)
+        with Image.open(image_field) as img:
+            img = ImageOps.exif_transpose(img)
+            w, h = img.size
+            if w * h > _COMPRESS_IMAGE_MAX_MEGAPIXELS * 1_000_000:
+                return None
+            img.thumbnail((max_width, max_width * 2), Image.BILINEAR)
+            rgb = img.convert('RGB')
             buf = BytesIO()
-            img.save(buf, format='JPEG', quality=quality, optimize=True)
+            rgb.save(buf, format='JPEG', quality=quality)
             buf.seek(0)
         return ImageReader(buf)
-    except Exception:
+    except BaseException:
         return None
     finally:
         try:
@@ -489,23 +498,28 @@ def _compress_image_for_pdf(image_field, max_width=1280, quality=75):
             pass
 
 
-def _compress_image_for_docx(image_field, max_width=1600, quality=80):
+def _compress_image_for_docx(image_field, max_width=800, quality=80):
     """
     Pripremi sliku za python-docx kao JPEG stream razumne veličine.
+
+    BILINEAR umjesto LANCZOS: višestruko brže za velike slike (izbjeći Gunicorn timeout).
+    Megapixel guard čita samo header i preskače slike > 8 MP bez dekodiranja piksela.
+    except BaseException hvata i SystemExit koji Gunicorn diže na SIGABRT (worker timeout).
     """
     try:
         image_field.open('rb')
-        with Image.open(image_field) as src:
-            img = src.convert('RGB')
-            if img.width > max_width:
-                ratio = max_width / float(img.width)
-                new_h = max(1, int(img.height * ratio))
-                img = img.resize((max_width, new_h), Image.LANCZOS)
+        with Image.open(image_field) as img:
+            img = ImageOps.exif_transpose(img)
+            w, h = img.size
+            if w * h > _COMPRESS_IMAGE_MAX_MEGAPIXELS * 1_000_000:
+                return None
+            img.thumbnail((max_width, max_width * 2), Image.BILINEAR)
+            rgb = img.convert('RGB')
             buf = BytesIO()
-            img.save(buf, format='JPEG', quality=quality, optimize=True)
+            rgb.save(buf, format='JPEG', quality=quality)
             buf.seek(0)
         return buf
-    except Exception:
+    except BaseException:
         return None
     finally:
         try:
@@ -532,10 +546,30 @@ def _get_cached_pdf(work_order, pdf_type):
     )
     for candidate in candidates:
         if str(candidate.filename or '').strip() == expected_filename:
+            file_name = getattr(candidate.file, 'name', '')
+            storage = getattr(candidate.file, 'storage', None)
+            if file_name and storage:
+                try:
+                    if storage.exists(file_name):
                         return candidate
+                except (FileNotFoundError, OSError, ValueError):
+                    pass
+            candidate.file = None
+            candidate.is_active = False
+            candidate.status = 'failed'
+            candidate.error_message = 'PDF datoteka nije dostupna.'
+            candidate.save(update_fields=['file', 'is_active', 'status', 'error_message', 'updated_at'])
     return None
 
 
+def _mark_generated_pdf_failed(generated_pdf, error_message):
+    generated_pdf.file = None
+    generated_pdf.is_active = False
+    generated_pdf.status = 'failed'
+    generated_pdf.error_message = error_message
+    generated_pdf.save(update_fields=['file', 'is_active', 'status', 'error_message', 'updated_at'])
+
+
 def _cleanup_expired_generated_pdfs():
     now = timezone.now()
     expired = GeneratedWorkOrderPdf.objects.filter(
@@ -546,10 +580,11 @@ def _cleanup_expired_generated_pdfs():
     for item in expired:
         if item.file:
             item.file.delete(save=False)
+        item.file = None
         item.is_active = False
         item.status = 'failed'
         item.error_message = 'PDF cache istekao.'
-        item.save(update_fields=['is_active', 'status', 'error_message', 'updated_at'])
+        item.save(update_fields=['file', 'is_active', 'status', 'error_message', 'updated_at'])
 
 
 def _parse_amount_decimal(value):
@@ -572,10 +607,11 @@ def _invalidate_work_order_pdf_cache(work_order, *, pdf_types=None):
     for cached in cache_qs:
         if cached.file:
             cached.file.delete(save=False)
+        cached.file = None
         cached.is_active = False
         cached.status = 'failed'
         cached.error_message = 'PDF cache invalidiran zbog promjene podataka.'
-        cached.save(update_fields=['is_active', 'status', 'error_message', 'updated_at'])
+        cached.save(update_fields=['file', 'is_active', 'status', 'error_message', 'updated_at'])
 
 
 def _upsert_additional_cost_row_from_invoice(invoice):
@@ -607,7 +643,11 @@ def _upsert_additional_cost_row_from_invoice(invoice):
 
 
 def _cached_pdf_file_response(generated_pdf, *, default_filename):
+    try:
         generated_pdf.file.open('rb')
+    except (FileNotFoundError, OSError, ValueError):
+        _mark_generated_pdf_failed(generated_pdf, 'PDF datoteka nije dostupna.')
+        raise DRFValidationError({"detail": "PDF nije dostupan ili je obrisan."})
     filename = generated_pdf.filename or default_filename
     response = FileResponse(generated_pdf.file, content_type='application/pdf')
     response['Content-Disposition'] = f'attachment; filename="{filename}"'
@@ -2410,6 +2450,26 @@ def _file_attachment(file_field, fallback_name):
     return (filename, content, _guess_content_type(filename))
 
 
+def _write_file_field_to_zip(archive, *, file_field, entry_name, chunk_size=64 * 1024):
+    if not file_field:
+        return False
+    file_field.open('rb')
+    try:
+        first_chunk = file_field.read(chunk_size)
+        if not first_chunk:
+            return False
+        with archive.open(entry_name, mode='w') as destination:
+            destination.write(first_chunk)
+            while True:
+                chunk = file_field.read(chunk_size)
+                if not chunk:
+                    break
+                destination.write(chunk)
+    finally:
+        file_field.close()
+    return True
+
+
 def _build_image_attachments_for_work_order(work_order):
     attachments = []
     photos = WorkOrderPhoto.objects.filter(is_active=True, work_order=work_order).order_by('created_at')
@@ -2968,7 +3028,7 @@ def _parse_year_month_params(request):
     return year, month
 
 
-def _build_monthly_service_tasks_archive_content(*, user, year, month):
+def _write_monthly_service_tasks_archive_entries(archive, *, user, year, month):
     from modules.task_management.models import Task
 
     tasks = list(
@@ -2988,8 +3048,7 @@ def _build_monthly_service_tasks_archive_content(*, user, year, month):
         raise DRFValidationError({'detail': 'Nema servisnih taskova za odabrani mjesec.'})
 
     used_names = set()
-    archive_buffer = BytesIO()
-    with zipfile.ZipFile(archive_buffer, mode='w', compression=zipfile.ZIP_DEFLATED) as archive:
+    entries_written = 0
     for task in tasks:
         work_order = task.work_order
         if work_order is None:
@@ -2998,14 +3057,28 @@ def _build_monthly_service_tasks_archive_content(*, user, year, month):
         base_name = _service_records_docx_filename(work_order, task)
         entry_name = _unique_zip_entry_name(base_name, used_names)
         archive.writestr(entry_name, docx_bytes)
+        entries_written += 1
+    if entries_written == 0:
+        raise DRFValidationError({'detail': 'Nije moguće kreirati ZIP za odabrani mjesec.'})
+    return entries_written
 
+
+def _build_monthly_service_tasks_archive_content(*, user, year, month):
+    archive_buffer = BytesIO()
+    with zipfile.ZipFile(archive_buffer, mode='w', compression=zipfile.ZIP_DEFLATED) as archive:
+        _write_monthly_service_tasks_archive_entries(
+            archive,
+            user=user,
+            year=year,
+            month=month,
+        )
     archive_content = archive_buffer.getvalue()
     if not archive_content:
         raise DRFValidationError({'detail': 'Nije moguće kreirati ZIP za odabrani mjesec.'})
     return archive_content
 
 
-def _build_monthly_work_orders_archive_content(*, user, year, month):
+def _write_monthly_work_orders_archive_entries(archive, *, user, year, month):
     from modules.task_management.models import Task
 
     monthly_tasks = (
@@ -3044,23 +3117,34 @@ def _build_monthly_work_orders_archive_content(*, user, year, month):
         raise DRFValidationError({'detail': 'Nema putnih naloga za odabrani mjesec.'})
 
     used_names = set()
-    archive_buffer = BytesIO()
-    with zipfile.ZipFile(archive_buffer, mode='w', compression=zipfile.ZIP_DEFLATED) as archive:
+    entries_written = 0
     for work_order in work_orders:
         pdf_bytes = _build_work_order_pdf(work_order)
         work_order_pdf_name = _unique_zip_entry_name(_pdf_filename(work_order, 'work_order'), used_names)
         archive.writestr(work_order_pdf_name, pdf_bytes)
+        entries_written += 1
 
         display_code = _work_order_display_code(work_order)
         invoices = work_order.invoices.filter(is_active=True).order_by('datum', 'created_at')
         for index, invoice in enumerate(invoices, start=1):
-                attachment = _file_attachment(invoice.image, fallback_name=f"invoice-{index}.bin")
-                if not attachment:
-                    continue
-                invoice_filename, content, _content_type = attachment
-                archive_path = f"Racuni/{display_code}/{invoice_filename}"
-                archive.writestr(_unique_zip_entry_name(archive_path, used_names), content)
+            file_name = Path(str(getattr(getattr(invoice, 'image', None), 'name', '') or f"invoice-{index}.bin")).name
+            archive_path = _unique_zip_entry_name(f"Racuni/{display_code}/{file_name}", used_names)
+            if _write_file_field_to_zip(archive, file_field=invoice.image, entry_name=archive_path):
+                entries_written += 1
+    if entries_written == 0:
+        raise DRFValidationError({'detail': 'Nije moguće kreirati ZIP za odabrani mjesec.'})
+    return entries_written
 
+
+def _build_monthly_work_orders_archive_content(*, user, year, month):
+    archive_buffer = BytesIO()
+    with zipfile.ZipFile(archive_buffer, mode='w', compression=zipfile.ZIP_DEFLATED) as archive:
+        _write_monthly_work_orders_archive_entries(
+            archive,
+            user=user,
+            year=year,
+            month=month,
+        )
     archive_content = archive_buffer.getvalue()
     if not archive_content:
         raise DRFValidationError({'detail': 'Nije moguće kreirati ZIP za odabrani mjesec.'})
@@ -3371,12 +3455,18 @@ def generated_archive_download(request, archive_id):
     if generated_archive is None:
         raise DRFValidationError({'detail': 'ZIP arhiva nije dostupna ili je istekla.'})
 
-    generated_archive.file.open('rb')
+    file_name = getattr(generated_archive.file, 'name', '')
+    storage = getattr(generated_archive.file, 'storage', None)
+    if not file_name or storage is None:
+        raise DRFValidationError({'detail': 'ZIP arhiva je prazna ili nedostupna.'})
     try:
-        archive_bytes = generated_archive.file.read()
-    finally:
-        generated_archive.file.close()
-    if not archive_bytes:
+        if not storage.exists(file_name):
+            raise DRFValidationError({'detail': 'ZIP arhiva je prazna ili nedostupna.'})
+    except (FileNotFoundError, OSError, ValueError):
+        raise DRFValidationError({'detail': 'ZIP arhiva je prazna ili nedostupna.'})
+    try:
+        generated_archive.file.open('rb')
+    except (FileNotFoundError, OSError, ValueError):
         raise DRFValidationError({'detail': 'ZIP arhiva je prazna ili nedostupna.'})
     filename = generated_archive.filename or _generated_archive_filename_for_user(
         request.user,
@@ -3384,10 +3474,13 @@ def generated_archive_download(request, archive_id):
         month=generated_archive.month,
         archive_type=generated_archive.archive_type,
     )
-    response = HttpResponse(archive_bytes, content_type='application/zip')
+    response = FileResponse(generated_archive.file, content_type='application/zip')
     response['Content-Disposition'] = f'attachment; filename="{filename}"'
     response['Cache-Control'] = 'private, max-age=3600'
-    response['Content-Length'] = str(len(archive_bytes))
+    try:
+        response['Content-Length'] = str(generated_archive.file.size)
+    except (OSError, ValueError, TypeError):
+        pass
     return response
 
 
@@ -3666,6 +3759,18 @@ class WorkOrderViewSet(viewsets.ModelViewSet):
         ).exclude(file='').exclude(file__isnull=True).first()
         if generated_pdf is None:
             raise DRFValidationError({"detail": "PDF nije dostupan ili je istekao."})
+        file_name = getattr(generated_pdf.file, 'name', '')
+        storage = getattr(generated_pdf.file, 'storage', None)
+        if not file_name or storage is None:
+            _mark_generated_pdf_failed(generated_pdf, 'PDF datoteka nije dostupna.')
+            raise DRFValidationError({"detail": "PDF nije dostupan ili je obrisan."})
+        try:
+            if not storage.exists(file_name):
+                _mark_generated_pdf_failed(generated_pdf, 'PDF datoteka nije dostupna.')
+                raise DRFValidationError({"detail": "PDF nije dostupan ili je obrisan."})
+        except (FileNotFoundError, OSError, ValueError):
+            _mark_generated_pdf_failed(generated_pdf, 'PDF datoteka nije dostupna.')
+            raise DRFValidationError({"detail": "PDF nije dostupan ili je obrisan."})
         return _cached_pdf_file_response(generated_pdf, default_filename=_pdf_filename(work_order, generated_pdf.pdf_type))
 
     @action(detail=True, methods=['get'], url_path='pdf-preview')

backend/scripts/cleanup_tmp_files.sh

@@ -0,0 +1,24 @@
+#!/bin/sh
+set -eu
+
+TMP_DIR="${APP_TMP_CLEANUP_DIR:-/tmp}"
+MAX_AGE_DAYS="${APP_TMP_CLEANUP_MAX_AGE_DAYS:-1}"
+PREFIXES="${APP_TMP_CLEANUP_PREFIXES:-erp-fleet-archive-}"
+
+if [ ! -d "$TMP_DIR" ]; then
+  echo "TMP dir ne postoji: $TMP_DIR"
+  exit 0
+fi
+
+OLD_IFS="$IFS"
+IFS=','
+for prefix in $PREFIXES; do
+  prefix_trimmed="$(echo "$prefix" | xargs)"
+  if [ -z "$prefix_trimmed" ]; then
+    continue
+  fi
+  find "$TMP_DIR" -maxdepth 1 -mindepth 1 -name "${prefix_trimmed}*" -mtime "+${MAX_AGE_DAYS}" -print -delete
+done
+IFS="$OLD_IFS"
+
+echo "TMP cleanup dovršen za $TMP_DIR (older than ${MAX_AGE_DAYS} day(s))."

docker-compose.prod.yml

@@ -37,7 +37,13 @@ services:
     environment:
       DEBUG: "False"
       DJANGO_SETTINGS_MODULE: core.settings.production
-    command: celery -A core worker --loglevel=info
+      CELERY_WORKER_PREFETCH_MULTIPLIER: "1"
+      CELERY_WORKER_MAX_TASKS_PER_CHILD: "20"
+      CELERY_WORKER_MAX_MEMORY_PER_CHILD: "350000"
+      APP_TMP_CLEANUP_DIR: "/tmp"
+      APP_TMP_CLEANUP_MAX_AGE_HOURS: "24"
+      APP_TMP_CLEANUP_PREFIXES: "erp-fleet-archive-"
+    command: celery -A core worker --loglevel=info --concurrency=${CELERY_WORKER_CONCURRENCY:-2}
     volumes:
       - media_volume:/app/media
     depends_on: