pass
-class Store:
+class Store (object):
"""Base class for all cumulus storage backends."""
+ def __new__ (cls, url, **kw):
+ """ Return the correct sub-class depending on url,
+ pass parsed url parameters to object
+ """
+ if cls != Store:
+ return super(Store, cls).__new__(cls, url, **kw)
+ (scheme, netloc, path, params, query, fragment) \
+ = urlparse.urlparse(url)
+
+ try:
+ cumulus = __import__('cumulus.store.%s' % scheme, globals())
+ subcls = getattr (cumulus.store, scheme).Store
+ obj = super(Store, cls).__new__(subcls, url, **kw)
+ obj.scheme = scheme
+ obj.netloc = netloc
+ obj.path = path
+ obj.params = params
+ obj.query = query
+ obj.fragment = fragment
+ return obj
+ except ImportError:
+ raise NotImplementedError, "Scheme %s not implemented" % scheme
+
def list(self, type):
- raise NotImplementedException
+ raise NotImplementedError
def get(self, type, name):
- raise NotImplementedException
+ raise NotImplementedError
def put(self, type, name, fp):
- raise NotImplementedException
+ raise NotImplementedError
def delete(self, type, name):
- raise NotImplementedException
+ raise NotImplementedError
+
+ def stat(self, type, name):
+ raise NotImplementedError
+
+ def scan(self):
+ """Cache file information stored in this backend.
+
+ This might make subsequent list or stat calls more efficient, but this
+ function is intended purely as a performance optimization."""
+
+ pass
+
+ def close(self):
+ """Tier down the connection explicitly if needed
+
+ Currently needed for sftp to be able to end the program."""
+
+ pass
+
+ def __del__(self):
+ self.close()
def open(url):
- (scheme, netloc, path, params, query, fragment) \
- = urlparse.urlparse(url)
-
- if scheme == "file":
- import cumulus.store.file
- return cumulus.store.file.FileStore(path)
- elif scheme == "s3":
- import cumulus.store.s3
- while path.startswith("/"): path = path[1:]
- (bucket, path) = path.split("/", 1)
- return cumulus.store.s3.S3Store(bucket, path)
- else:
- raise NotImplementedException
+ return Store(url)