Fix: Better error handling for webassets + cache

src/octoprint/server/__init__.py

@@ -740,13 +740,10 @@ class Server():
 			for entry in ("webassets", ".webassets-cache"):
 				path = os.path.join(base_folder, entry)
 				self._logger.debug("Deleting {path}...".format(**locals()))
-				if os.path.isdir(path):
-					shutil.rmtree(path, ignore_errors=True)
-				elif os.path.isfile(path):
-					try:
-						os.remove(path)
-					except:
-						self._logger.exception("Exception while trying to delete {entry} from {base_folder}".format(**locals()))
+				shutil.rmtree(path, ignore_errors=True)
+				self._logger.debug("Creating {path}...".format(**locals()))
+				os.makedirs(path)
+				self._logger.info("Reset webasset folder {path}...".format(**locals()))
 
 		AdjustedEnvironment = type(Environment)(Environment.__name__, (Environment,), dict(
 			resolver_class=util.flask.PluginAssetResolver

src/octoprint/server/util/flask.py

@@ -123,12 +123,19 @@ def enable_additional_translations(default_locale="en", additional_folders=None)
 
 def fix_webassets_cache():
 	from webassets import cache
-	import os
-	import tempfile
-	import pickle
-	import shutil
+
+	error_logger = logging.getLogger(__name__ + ".fix_webassets_cache")
 
 	def fixed_set(self, key, data):
+		import os
+		import tempfile
+		import pickle
+		import shutil
+
+		if not os.path.exists(self.directory):
+			error_logger.warn("Cache directory {} doesn't exist, not going "
+			                  "to attempt to write cache file".format(self.directory))
+
 		md5 = '%s' % cache.make_md5(self.V, key)
 		filename = os.path.join(self.directory, md5)
 		fd, temp_filename = tempfile.mkstemp(prefix='.' + md5,
@@ -148,6 +155,11 @@ def fix_webassets_cache():
 		import warnings
 		from webassets.cache import make_md5
 
+		if not os.path.exists(self.directory):
+			error_logger.warn("Cache directory {} doesn't exist, not going "
+			                  "to attempt to read cache file".format(self.directory))
+			return None
+
 		try:
 			hash = make_md5(self.V, key)
 		except IOError as e:
@@ -194,12 +206,15 @@ def fix_webassets_filtertool():
 		try:
 			content = func().getvalue()
 			if self.cache:
-				log.debug('Storing result in cache with key %s', key,)
-				self.cache.set(key, content)
+				try:
+					log.debug('Storing result in cache with key %s', key,)
+					self.cache.set(key, content)
+				except:
+					error_logger.exception("Got an exception while trying to save file to cache, not caching")
 			return MemoryHunk(content)
 		except:
 			error_logger.exception("Got an exception while trying to apply filter, ignoring file")
-			return MemoryHunk("")
+			return MemoryHunk(u"")
 
 	FilterTool._wrap_cache = fixed_wrap_cache