Do access logging via custom request header instead of global flag

We don't want any weird things to happen due to multithreading...

src/octoprint/server/__init__.py

@@ -815,9 +815,13 @@ class Server(object):
 							self._logger.info("Preemptively caching {} (plugin {}) for {!r}".format(route, plugin, kwargs))
 						else:
 							self._logger.info("Preemptively caching {} for {!r}".format(route, kwargs))
+
+						headers = kwargs.get("headers", dict())
+						headers["X-Preemptive-Record"] = "no"
+						kwargs["headers"] = headers
+
 						builder = EnvironBuilder(**kwargs)
-						with preemptive_cache.disable_access_logging():
-							app(builder.get_environ(), lambda *a, **kw: None)
+						app(builder.get_environ(), lambda *a, **kw: None)
 					except:
 						self._logger.exception("Error while trying to preemptively cache {} for {!r}".format(route, kwargs))
 

src/octoprint/server/util/flask.py

@@ -402,9 +402,7 @@ class PreemptiveCache(object):
 		self.cachefile = cachefile
 
 		self._lock = threading.RLock()
-		self._log_lock = threading.RLock()
 		self._logger = logging.getLogger(__name__ + "." + self.__class__.__name__)
-		self._log_access = True
 
 	def record(self, data, unless=None, root=None):
 		if callable(unless) and unless():
@@ -438,13 +436,6 @@ class PreemptiveCache(object):
 
 		return False
 
-	@contextlib.contextmanager
-	def disable_access_logging(self):
-		with self._log_lock:
-			self._log_access = False
-			yield
-			self._log_access = True
-
 	def clean_all_data(self, cleanup_function):
 		assert callable(cleanup_function)
 
@@ -505,13 +496,6 @@ class PreemptiveCache(object):
 			self.set_all_data(all_data)
 
 	def add_data(self, root, data):
-		with self._log_lock:
-			if not self._log_access:
-				self._logger.debug(
-					"Not updating timestamp and counter for {} and {!r}, currently flagged as disabled".format(root,
-					                                                                                           data))
-				return
-
 		def split_matched_and_unmatched(entry, entries):
 			matched = []
 			unmatched = []

src/octoprint/server/views.py

@@ -34,9 +34,13 @@ def _preemptive_unless(base_url=None):
 	if base_url is None:
 		base_url = request.url_root
 
-	return not settings().getBoolean(["devel", "cache", "preemptive"]) \
-	       or base_url in settings().get(["server", "preemptiveCache", "exceptions"]) \
-	       or not (base_url.startswith("http://") or base_url.startswith("https://"))
+	cache_disabled = not settings().getBoolean(["devel", "cache", "preemptive"]) \
+	                 or base_url in settings().get(["server", "preemptiveCache", "exceptions"]) \
+	                 or not (base_url.startswith("http://") or base_url.startswith("https://"))
+
+	recording_disabled = request.headers.get("X-Preemptive-Record", "yes") == "no"
+
+	return cache_disabled or recording_disabled
 
 def _preemptive_data(path=None, base_url=None):
 	if path is None: