async def list_versions(
self, entry_id: EntryID) -> Dict[int, Tuple[DateTime, DeviceID]]:
"""
Raises:
FSError
FSRemoteOperationError
FSBackendOfflineError
FSWorkspaceInMaintenance
FSRemoteManifestNotFound
"""
with translate_backend_cmds_errors():
rep = await self.backend_cmds.vlob_list_versions(
VlobID(entry_id.uuid))
if rep["status"] == "not_allowed":
# Seems we lost the access to the realm
raise FSWorkspaceNoReadAccess(
"Cannot load manifest: no read access")
elif rep["status"] == "not_found":
raise FSRemoteManifestNotFound(entry_id)
elif rep["status"] == "in_maintenance":
raise FSWorkspaceInMaintenance(
"Cannot download vlob while the workspace is in maintenance")
elif rep["status"] != "ok":
raise FSError(f"Cannot fetch vlob {entry_id}: `{rep['status']}`")
return rep["versions"]
async def load_manifest(
self,
entry_id: EntryID,
version: int = None,
timestamp: Pendulum = None,
expected_backend_timestamp: Pendulum = None,
) -> RemoteManifest:
"""
Download a manifest.
Only one from version or timestamp parameters can be specified at the same time.
expected_backend_timestamp enables to check a timestamp against the one returned by the
backend.
Raises:
FSError
FSBackendOfflineError
FSWorkspaceInMaintenance
FSRemoteManifestNotFound
FSBadEncryptionRevision
FSWorkspaceNoAccess
"""
if timestamp is not None and version is not None:
raise FSError(
f"Supplied both version {version} and timestamp `{timestamp}` for manifest "
f"`{entry_id}`")
# Download the vlob
workspace_entry = self.get_workspace_entry()
rep = await self._backend_cmds(
"vlob_read",
workspace_entry.encryption_revision,
entry_id,
version=version,
timestamp=timestamp if version is None else None,
)
if rep["status"] == "not_found":
raise FSRemoteManifestNotFound(entry_id)
elif rep["status"] == "not_allowed":
# Seems we lost the access to the realm
raise FSWorkspaceNoReadAccess(
"Cannot load manifest: no read access")
elif rep["status"] == "bad_version":
raise FSRemoteManifestNotFoundBadVersion(entry_id)
elif rep["status"] == "bad_timestamp":
raise FSRemoteManifestNotFoundBadTimestamp(entry_id)
elif rep["status"] == "bad_encryption_revision":
raise FSBadEncryptionRevision(
f"Cannot fetch vlob {entry_id}: Bad encryption revision provided"
)
elif rep["status"] == "in_maintenance":
raise FSWorkspaceInMaintenance(
f"Cannot download vlob while the workspace is in maintenance")
elif rep["status"] != "ok":
raise FSError(f"Cannot fetch vlob {entry_id}: `{rep['status']}`")
expected_version = rep["version"]
expected_author = rep["author"]
expected_timestamp = rep["timestamp"]
if version not in (None, expected_version):
raise FSError(
f"Backend returned invalid version for vlob {entry_id} (expecting {version}, "
f"got {expected_version})")
if expected_backend_timestamp and expected_backend_timestamp != expected_timestamp:
raise FSError(
f"Backend returned invalid expected timestamp for vlob {entry_id} at version "
f"{version} (expecting {expected_backend_timestamp}, got {expected_timestamp})"
)
author = await self.remote_device_manager.get_device(expected_author)
try:
remote_manifest = RemoteManifest.decrypt_verify_and_load(
rep["blob"],
key=workspace_entry.key,
author_verify_key=author.verify_key,
expected_author=expected_author,
expected_timestamp=expected_timestamp,
expected_version=expected_version,
expected_id=entry_id,
)
except DataError as exc:
raise FSError(f"Cannot decrypt vlob: {exc}") from exc
# Finally make sure author was allowed to create this manifest
role_at_timestamp = await self._get_user_realm_role_at(
expected_author.user_id, expected_timestamp)
if role_at_timestamp is None:
raise FSError(
f"Manifest was created at {expected_timestamp} by `{expected_author}` "
"which had no right to access the workspace at that time")
elif role_at_timestamp == RealmRole.READER:
raise FSError(
f"Manifest was created at {expected_timestamp} by `{expected_author}` "
"which had write right on the workspace at that time")
return remote_manifest
async def load_manifest(
self,
entry_id: EntryID,
version: Optional[int] = None,
timestamp: Optional[DateTime] = None,
expected_backend_timestamp: Optional[DateTime] = None,
workspace_entry: Optional[WorkspaceEntry] = None,
) -> BaseRemoteManifest:
"""
Download a manifest.
Only one from version or timestamp parameters can be specified at the same time.
expected_backend_timestamp enables to check a timestamp against the one returned by the
backend.
Raises:
FSError
FSBackendOfflineError
FSRemoteOperationError
FSWorkspaceInMaintenance
FSRemoteManifestNotFound
FSBadEncryptionRevision
FSWorkspaceNoAccess
FSUserNotFoundError
FSDeviceNotFoundError
FSInvalidTrustchainError
"""
assert (timestamp is None or version is None
), "Either timestamp or version argument should be provided"
# Get the current and requested workspace entry
# They're usually the same, except when loading from a workspace while it's in maintenance
current_workspace_entry = self.get_workspace_entry()
workspace_entry = current_workspace_entry if workspace_entry is None else workspace_entry
# Download the vlob
with translate_backend_cmds_errors():
rep = await self.backend_cmds.vlob_read(
workspace_entry.encryption_revision,
VlobID(entry_id.uuid),
version=version,
timestamp=timestamp if version is None else None,
)
# Special case for loading manifest while in maintenance.
# This is done to allow users to fetch data from a workspace while it's being reencrypted.
# If the workspace is in maintenance for another reason (such as garbage collection),
# the recursive call to load manifest will simply also fail with an FSWorkspaceInMaintenance.
if (rep["status"] == "in_maintenance"
and workspace_entry.encryption_revision
== current_workspace_entry.encryption_revision):
# Getting the last workspace entry with the previous encryption revision
# requires one or several calls to the backend, meaning the following exceptions might get raised:
# - FSError
# - FSBackendOfflineError
# - FSWorkspaceInMaintenance
# It is fine to let those exceptions bubble up as there all valid reasons for failing to load a manifest.
previous_workspace_entry = await self.get_previous_workspace_entry(
)
if previous_workspace_entry is not None:
# Make sure we don't fall into an infinite loop because of some other bug
assert (previous_workspace_entry.encryption_revision <
self.get_workspace_entry().encryption_revision)
# Recursive call to `load_manifest`, requiring an older encryption revision than the current one
return await self.load_manifest(
entry_id,
version=version,
timestamp=timestamp,
expected_backend_timestamp=expected_backend_timestamp,
workspace_entry=previous_workspace_entry,
)
if rep["status"] == "not_found":
raise FSRemoteManifestNotFound(entry_id)
elif rep["status"] == "not_allowed":
# Seems we lost the access to the realm
raise FSWorkspaceNoReadAccess(
"Cannot load manifest: no read access")
elif rep["status"] == "bad_version":
raise FSRemoteManifestNotFoundBadVersion(entry_id)
elif rep["status"] == "bad_encryption_revision":
raise FSBadEncryptionRevision(
f"Cannot fetch vlob {entry_id}: Bad encryption revision provided"
)
elif rep["status"] == "in_maintenance":
raise FSWorkspaceInMaintenance(
"Cannot download vlob while the workspace is in maintenance")
elif rep["status"] != "ok":
raise FSError(f"Cannot fetch vlob {entry_id}: `{rep['status']}`")
expected_version = rep["version"]
expected_author = rep["author"]
expected_timestamp = rep["timestamp"]
if version not in (None, expected_version):
raise FSError(
f"Backend returned invalid version for vlob {entry_id} (expecting {version}, "
f"got {expected_version})")
if expected_backend_timestamp and expected_backend_timestamp != expected_timestamp:
raise FSError(
f"Backend returned invalid expected timestamp for vlob {entry_id} at version "
f"{version} (expecting {expected_backend_timestamp}, got {expected_timestamp})"
)
with translate_remote_devices_manager_errors():
author = await self.remote_devices_manager.get_device(
expected_author)
try:
remote_manifest = BaseRemoteManifest.decrypt_verify_and_load(
rep["blob"],
key=workspace_entry.key,
author_verify_key=author.verify_key,
expected_author=expected_author,
expected_timestamp=expected_timestamp,
expected_version=expected_version,
expected_id=entry_id,
)
except DataError as exc:
raise FSError(f"Cannot decrypt vlob: {exc}") from exc
# Get the timestamp of the last role for this particular user
author_last_role_granted_on = rep["author_last_role_granted_on"]
# Compatibility with older backends (best effort strategy)
if author_last_role_granted_on is None:
author_last_role_granted_on = self.device.timestamp()
# Finally make sure author was allowed to create this manifest
role_at_timestamp = await self._get_user_realm_role_at(
expected_author.user_id, expected_timestamp,
author_last_role_granted_on)
if role_at_timestamp is None:
raise FSError(
f"Manifest was created at {expected_timestamp} by `{expected_author}` "
"which had no right to access the workspace at that time")
elif role_at_timestamp == RealmRole.READER:
raise FSError(
f"Manifest was created at {expected_timestamp} by `{expected_author}` "
"which had no right to write on the workspace at that time")
return remote_manifest