Label printing errors (#6450)

* Enhance error handling for label printing

* Better feedback in forms

* Raise error to user - no need to log

InvenTree/label/api.py

@@ -4,6 +4,7 @@ from django.core.exceptions import FieldError, ValidationError
 from django.http import JsonResponse
 from django.urls import include, path, re_path
 from django.utils.decorators import method_decorator
+from django.utils.translation import gettext_lazy as _
 from django.views.decorators.cache import cache_page, never_cache
 
 from django_filters.rest_framework import DjangoFilterBackend
@@ -13,6 +14,7 @@ from rest_framework.request import clone_request
 
 import build.models
 import common.models
+import InvenTree.exceptions
 import InvenTree.helpers
 import label.models
 import label.serializers
@@ -232,9 +234,14 @@ class LabelPrintMixin(LabelFilterMixin):
         # At this point, we offload the label(s) to the selected plugin.
         # The plugin is responsible for handling the request and returning a response.
 
+        try:
             result = plugin.print_labels(
                 label, items_to_print, request, printing_options=request.data
             )
+        except ValidationError as e:
+            raise (e)
+        except Exception as e:
+            raise ValidationError([_('Error printing label'), str(e)])
 
         if isinstance(result, JsonResponse):
             result['plugin'] = plugin.plugin_slug()

InvenTree/plugin/base/label/mixins.py

@@ -2,13 +2,16 @@
 
 from typing import Union
 
+from django.core.exceptions import ValidationError
 from django.http import JsonResponse
+from django.utils.translation import gettext_lazy as _
 
 import pdf2image
 from rest_framework import serializers
 from rest_framework.request import Request
 
 from common.models import InvenTreeSetting
+from InvenTree.exceptions import log_error
 from InvenTree.tasks import offload_task
 from label.models import LabelTemplate
 from plugin.base.label import label as plugin_label
@@ -47,7 +50,11 @@ class LabelPrintingMixin:
             label: The LabelTemplate object to render
             request: The HTTP request object which triggered this print job
         """
+        try:
             return label.render(request)
+        except Exception as e:
+            log_error('label.render_to_pdf')
+            raise ValidationError(_('Error rendering label to PDF'))
 
     def render_to_html(self, label: LabelTemplate, request, **kwargs):
         """Render this label to HTML format.
@@ -56,7 +63,11 @@ class LabelPrintingMixin:
             label: The LabelTemplate object to render
             request: The HTTP request object which triggered this print job
         """
+        try:
             return label.render_as_string(request)
+        except Exception as e:
+            log_error('label.render_to_html')
+            raise ValidationError(_('Error rendering label to HTML'))
 
     def render_to_png(self, label: LabelTemplate, request=None, **kwargs):
         """Render this label to PNG format."""
@@ -71,8 +82,11 @@ class LabelPrintingMixin:
         dpi = kwargs.get('dpi', InvenTreeSetting.get_setting('LABEL_DPI', 300))
 
         # Convert to png data
-        png = pdf2image.convert_from_bytes(pdf_data, dpi=dpi)[0]
-        return png
+        try:
+            return pdf2image.convert_from_bytes(pdf_data, dpi=dpi)[0]
+        except Exception as e:
+            log_error('label.render_to_png')
+            raise ValidationError(_('Error rendering label to PNG'))
 
     def print_labels(
         self,