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34 class BaseBackend(object):
35 """Abstract backend class that serves as a reference for actual implementations.
37 The purpose of the backend is to provide the necessary functions for handling data
38 and metadata. It is responsible for the actual storage and retrieval of information.
40 Note that the account level is always valid as it is checked from another subsystem.
42 The following variables should be available:
43 'hash_algorithm': Suggested is 'sha256'
44 'block_size': Suggested is 4MB
47 def delete_account(self, account):
48 """Delete the account with the given name.
51 IndexError: Account is not empty
55 def get_account_meta(self, account, until=None):
56 """Return a dictionary with the account metadata.
58 The keys returned are all user-defined, except:
59 'name': The account name
60 'count': The number of containers (or 0)
61 'bytes': The total data size (or 0)
62 'modified': Last modification timestamp (overall)
63 'until_timestamp': Last modification until the timestamp provided
67 def update_account_meta(self, account, meta, replace=False):
68 """Update the metadata associated with the account.
71 'meta': Dictionary with metadata to update
72 'replace': Replace instead of update
76 def list_containers(self, account, marker=None, limit=10000, until=None):
77 """Return a list of container (name, version_id) tuples existing under an account.
80 'marker': Start list from the next item after 'marker'
81 'limit': Number of containers to return
85 def put_container(self, account, container):
86 """Create a new container with the given name.
89 NameError: Container already exists
93 def delete_container(self, account, container):
94 """Delete the container with the given name.
97 NameError: Container does not exist
98 IndexError: Container is not empty
102 def get_container_meta(self, account, container, until=None):
103 """Return a dictionary with the container metadata.
105 The keys returned are all user-defined, except:
106 'name': The container name
107 'count': The number of objects
108 'bytes': The total data size
109 'modified': Last modification timestamp (overall)
110 'until_timestamp': Last modification until the timestamp provided
113 NameError: Container does not exist
117 def update_container_meta(self, account, container, meta, replace=False):
118 """Update the metadata associated with the container.
121 'meta': Dictionary with metadata to update
122 'replace': Replace instead of update
125 NameError: Container does not exist
129 def list_objects(self, account, container, prefix='', delimiter=None, marker=None, limit=10000, virtual=True, keys=[], until=None):
130 """Return a list of object (name, version_id) tuples existing under a container.
133 'prefix': List objects starting with 'prefix'
134 'delimiter': Return unique names before 'delimiter' and after 'prefix'
135 'marker': Start list from the next item after 'marker'
136 'limit': Number of objects to return
137 'virtual': If not set, the result will only include names starting\
138 with 'prefix' and ending without a 'delimiter' or with\
139 the first occurance of the 'delimiter' after 'prefix'.\
140 If set, the result will include all names after 'prefix',\
141 up to and including the 'delimiter' if it is found
142 'keys': Include objects that have meta with the keys in the list
145 NameError: Container does not exist
149 def list_object_meta(self, account, container, until=None):
150 """Return a list with all the container's object meta keys.
153 NameError: Container does not exist
157 def get_object_meta(self, account, container, name, version=None):
158 """Return a dictionary with the object metadata.
160 The keys returned are all user-defined, except:
161 'name': The object name
162 'bytes': The total data size
163 'modified': Last modification timestamp (overall)
164 'version': The version identifier
165 'version_timestamp': The version's modification timestamp
168 NameError: Container/object does not exist
169 IndexError: Version does not exist
173 def update_object_meta(self, account, container, name, meta, replace=False):
174 """Update the metadata associated with the object.
177 'meta': Dictionary with metadata to update.
178 'replace': Replace instead of update
181 NameError: Container/object does not exist
185 def get_object_hashmap(self, account, container, name, version=None):
186 """Return the object's size and a list with partial hashes.
189 NameError: Container/object does not exist
190 IndexError: Version does not exist
194 def update_object_hashmap(self, account, container, name, size, hashmap):
195 """Create/update an object with the specified size and partial hashes.
198 NameError: Container does not exist
202 def copy_object(self, account, src_container, src_name, dest_container, dest_name, dest_meta={}, replace_meta=False, src_version=None):
203 """Copy an object's data and metadata.
206 'dest_meta': Dictionary with metadata to changes from source to destination
207 'replace_meta': Replace metadata instead of update
208 'src_version': Copy from the version provided.
211 NameError: Container/object does not exist
212 IndexError: Version does not exist
216 def move_object(self, account, src_container, src_name, dest_container, dest_name, dest_meta={}, replace_meta=False, src_version=None):
217 """Move an object's data and metadata.
220 'dest_meta': Dictionary with metadata to changes from source to destination
221 'replace_meta': Replace metadata instead of update
222 'src_version': Copy from the version provided.
225 NameError: Container/object does not exist
226 IndexError: Version does not exist
230 def delete_object(self, account, container, name):
234 NameError: Container/object does not exist
238 def list_versions(self, account, container, name):
239 """Return a list of version (version_id, version_modified) tuples for an object."""
242 def get_block(self, hash):
243 """Return a block's data.
246 NameError: Block does not exist
250 def put_block(self, data):
251 """Store a block and return the hash."""
254 def update_block(self, hash, data, offset=0):
255 """Update a known block and return the hash.
258 IndexError: Offset or data outside block limits