SW-1290 avoid crashing on import failure (mrbeam#1507)

* add try catch on importing octoprint_mrbeamdoc
* add wraps decorator to keep the same function name so that octoprint finds the handler and adds it to flask
* added tests for empty import

Author: Yelko-mrbeam

octoprint_mrbeam/decorator/__init__.py

@@ -0,0 +1,27 @@
+from functools import wraps
+
+from octoprint_mrbeam.model import EmptyImport
+
+
+def prevent_execution_on_import_error(import_to_check, default_return=None, callable=None, params=None):
+    def decorator(function):
+        @wraps(function)
+        def wrapper(*args, **kwargs):
+            if is_empty_import(import_to_check):
+                if callable is None:
+                    return default_return
+                elif params is None:
+                    return callable()
+                else:
+                    return callable(*params)
+
+            result = function(*args, **kwargs)
+            return result
+
+        return wrapper
+
+    return decorator
+
+
+def is_empty_import(import_to_check):
+    return isinstance(import_to_check, EmptyImport)

octoprint_mrbeam/decorator/catch_import_error.py

@@ -0,0 +1 @@
+from octoprint_mrbeam.model.empty_import import EmptyImport

octoprint_mrbeam/model/__init__.py

@@ -0,0 +1,22 @@
+class EmptyImport(object):
+
+    def __init__(self, module, default_return=None):
+        super(EmptyImport, self).__init__()
+        self.default_return = default_return
+        self.error_message = 'Error occurred trying to import module {module}'.format(module=module)
+        self.log_error()
+
+    def log_error(self):
+        try:
+            from octoprint_mrbeam import mrb_logger
+            logger = mrb_logger("octoprint.plugins.mrbeam.model.EmptyImport")
+            logger.error(self.error_message)
+        except ImportError:
+            return False
+        return True
+
+    def __call__(self, **kwargs):
+        return self.default_return
+
+    def __getattr__(self, name):
+        return self

octoprint_mrbeam/model/empty_import.py

@@ -1,7 +1,16 @@
 import octoprint.plugin
 from flask import abort, send_file
-from octoprint_mrbeamdoc.exception.mrbeam_doc_not_found import MrBeamDocNotFoundException
-from octoprint_mrbeamdoc.utils.mrbeam_doc_utils import MrBeamDocUtils
+
+from octoprint_mrbeam.decorator.catch_import_error import prevent_execution_on_import_error
+from octoprint_mrbeam.model import EmptyImport
+
+try:
+    from octoprint_mrbeamdoc.exception.mrbeam_doc_not_found import MrBeamDocNotFoundException
+    from octoprint_mrbeamdoc.utils.mrbeam_doc_utils import MrBeamDocUtils
+except ImportError:
+    MrBeamDocUtils = EmptyImport("from octoprint_mrbeamdoc.utils.mrbeam_doc_utils import MrBeamDocUtils")
+    MrBeamDocNotFoundException = EmptyImport(
+        "from octoprint_mrbeamdoc.exception.mrbeam_doc_not_found import MrBeamDocNotFoundException")
 
 
 class DocsRestHandlerMixin:
@@ -11,6 +20,7 @@ class DocsRestHandlerMixin:
 
     @octoprint.plugin.BlueprintPlugin.route(
         "/docs/<string:model>/<string:language>/<string:doctype>.<string:extension>", methods=["GET"])
+    @prevent_execution_on_import_error(MrBeamDocUtils, callable=abort, params=[404])
     def get_doc(self, model, doctype, language, extension):
         self._logger.debug(
             'Request to Model: %(model)s Doctype: %(doctype)s Language: %(language)s Extension:%(extension)s',

octoprint_mrbeam/rest_handler/docs_handler.py

@@ -1,6 +1,14 @@
 from flask_babel import get_locale
-from octoprint_mrbeamdoc.enum.supported_languages import SupportedLanguage
-from octoprint_mrbeamdoc.utils.mrbeam_doc_utils import MrBeamDocUtils
+
+from octoprint_mrbeam.decorator.catch_import_error import prevent_execution_on_import_error
+from octoprint_mrbeam.model import EmptyImport
+
+try:
+    from octoprint_mrbeamdoc.enum.supported_languages import SupportedLanguage
+    from octoprint_mrbeamdoc.utils.mrbeam_doc_utils import MrBeamDocUtils
+except ImportError:
+    MrBeamDocUtils = EmptyImport("from octoprint_mrbeamdoc.utils.mrbeam_doc_utils import MrBeamDocUtils")
+    SupportedLanguage = EmptyImport("from octoprint_mrbeamdoc.enum.supported_languages import SupportedLanguage")
 
 from octoprint_mrbeam.model.burger_menu_model import BurgerMenuModel
 
@@ -14,6 +22,7 @@ def __init__(self, logger, document_service):
         self._logger = logger
         self._document_service = document_service
 
+    @prevent_execution_on_import_error(MrBeamDocUtils, default_return=BurgerMenuModel())
     def get_burger_menu_model(self, mrbeam_model):
         """
         mrbeam_model String: Name of the running mrbeam_model

octoprint_mrbeam/services/burger_menu_service.py

@@ -1,8 +1,20 @@
-from octoprint_mrbeamdoc.utils.mrbeam_doc_utils import MrBeamDocUtils
+from octoprint_mrbeam.decorator.catch_import_error import prevent_execution_on_import_error
+from octoprint_mrbeam.model import EmptyImport
+
+try:
+    from octoprint_mrbeamdoc.utils.mrbeam_doc_utils import MrBeamDocUtils
+except ImportError:
+    MrBeamDocUtils = EmptyImport("from octoprint_mrbeamdoc.utils.mrbeam_doc_utils import MrBeamDocUtils")
 
 from octoprint_mrbeam.model.settings_model import SettingsModel, AboutModel
 
 
+def _empty_settings_model():
+    settings_model = SettingsModel()
+    settings_model.about = AboutModel()
+    return settings_model
+
+
 class SettingsService:
     """
     In this class we gather all the service layer calculations needed regarding settings
@@ -12,6 +24,7 @@ def __init__(self, logger, document_service):
         self._logger = logger
         self._document_service = document_service
 
+    @prevent_execution_on_import_error(MrBeamDocUtils, callable=_empty_settings_model)
     def get_template_settings_model(self, mrbeam_model):
         """
         mrbeam_model String: Name of the running mrbeam_model
@@ -28,8 +41,3 @@ def get_template_settings_model(self, mrbeam_model):
         settings_model.about = AboutModel(
             support_documents=[self._document_service.get_documents_for(definition) for definition in definitions])
         return settings_model
-
-    def _empty_settings_model(self):
-        settings_model = SettingsModel()
-        settings_model.about = AboutModel()
-        return settings_model

octoprint_mrbeam/services/settings_service.py

@@ -0,0 +1,15 @@
+from unittest import TestCase
+
+from octoprint_mrbeam.model import EmptyImport
+
+
+class TestEmptyImportClass(TestCase):
+
+    def test_random_attribute_returns_self(self):
+        empty_import = EmptyImport("module name")
+        self.assertIs(empty_import.documents, empty_import)
+
+    def test_random_method_returns_none(self):
+        empty_import = EmptyImport("module name")
+        result = empty_import.random_method()
+        self.assertIs(result, None)