Add funcdocs to Cache-class and methods

This commit is contained in:
Thor77 2018-01-20 10:09:48 +01:00
parent 74444edd55
commit 7b3ecb039b
1 changed files with 48 additions and 0 deletions

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@ -10,18 +10,48 @@ CachedLog = namedtuple('CachedLog', ['path', 'hash', 'events'])
def _calculate_hash(path):
'''
Calculate hash of a file using sha256
:param path: path to file
:type path: str
:return: hash of the file
:rtype: str
'''
with open(path, 'rb') as f:
return hashlib.sha256(f.read()).hexdigest()
class Cache(MutableMapping):
'''
Cache for parsed events from a logfile
'''
def __init__(self, path, data={}):
'''
Initialize Cache at `path`
:param path: path to cache file
:param data: initial cached data
:type path: str
:type data: dict
'''
self.path = path
self.store = data
self.initial_store_version = self.store.setdefault('version', 0)
@classmethod
def read(cls, path):
'''
Create a new Cache-instance with data read from `path`
:param path: path to cache file
:type path: str
:return: Cache-instance with data from `path`
:rtype: tsstats.cache.Cache
'''
data = {}
if os.path.exists(path):
logger.debug('Reading cache from %s', path)
@ -33,6 +63,15 @@ class Cache(MutableMapping):
return cls(path, data)
def write(self, path=None):
'''
Dump cache to `path`
but only if there were any changes, if not, it will silently skip
writing
:param path: path to cache file
:type path: str
'''
if not path:
path = self.path
if self.initial_store_version == self.store['version']:
@ -43,6 +82,15 @@ class Cache(MutableMapping):
pickle.dump(self.store, f)
def needs_parsing(self, path):
'''
Determine if a logfile needs parsing (=> is not cached or was updated)
:param path: path to logfile
:type path: str
:return: if parsing is necessary for logfile at `path`
:rtype: bool
'''
if path not in self.store:
return True
return _calculate_hash(path) != self.store[path].hash