Coverage for mddb_workflow/utils/cache.py: 78%

1from mddb_workflow.utils.auxiliar import load_json, save_json 

2from mddb_workflow.utils.type_hints import * 

3 

4# The cache is used to store data to be reused between different runs 

5class Cache: 

6 def __init__ (self, cache_file : 'File'): 

7 # Save the previous cache file 

8 self.file = cache_file 

9 # Set an auxiliar file which is used to not overwrite directly the previous cache 

10 self._aux_file = cache_file.get_prefixed_file('.aux') 

11 # Set a dict to store the actual cached data 

12 self.data = {} 

13 # Load data from the cache file, if it already exists 

14 self.load() 

15 # Save the entry for the first time 

16 self.save() 

17 

18 # Read a value from the cache 

19 def retrieve (self, key : str, fallback = None): 

20 return self.data.get(key, fallback) 

21 

22 # Update the cache and save it to disk 

23 def update (self, key : str, value): 

24 self.data[key] = value 

25 self.save() 

26 

27 # Delete a value in the cache 

28 def delete (self, key : str): 

29 if key not in self.data: return 

30 del self.data[key] 

31 self.save() 

32 

33 # Reset the cache 

34 # This is called when some input files are modified 

35 def reset (self): 

36 self.data = {} 

37 self.save() 

38 

39 # Load the cache to memory, as a dict 

40 def load (self): 

41 # Load data from the cache file, if it already exists 

42 if not self.file.exists: return 

43 # Read the cache in disk 

44 self.data = load_json(self.file.path) 

45 

46 # Save the cache to disk, as a json file 

47 def save (self): 

48 # Write entries to disk 

49 # Write to the auxiliar file, thus not overwritting the original cache yet 

50 save_json(self.data, self._aux_file.path, indent = 4) 

51 # If the new cache is successfully written then replace the old one 

52 self._aux_file.rename_to(self.file)