def getData(self, path):
"""get data for track and slice. Save data in persistent cache for
further use.
For functions, path should be an empty tuple.
"""
if path:
key = DataTree.path2str(path)
else:
key = "all"
result, fromcache = None, False
# trackers with options are not cached
if not self.nocache and not self.tracker_options:
try:
result = self.cache[key]
fromcache = True
except KeyError:
pass
except RuntimeError as msg:
raise RuntimeError(
"error when accessing key %s from cache: %s "
"- potential problem with unpickable object?" % (key, msg))
kwargs = {}
if self.tracker_options:
kwargs['options'] = self.tracker_options
if result is None:
try:
result = self.tracker(*path, **kwargs)
except Exception as msg:
self.warn("exception for tracker '%s', path '%s': msg=%s" %
(str(self.tracker),
DataTree.path2str(
path),
msg))
if VERBOSE:
self.warn(traceback.format_exc())
raise
# store in cache
if not self.nocache and not fromcache:
# exception - do not store data frames
# test with None fails for some reason
self.cache[key] = result
return result
