def load_session(cls, unit_list, storage, early_cb=None, flags=None):
"""
Load a previously checkpointed session.
This method allows one to re-open a session that was previously
created by :meth:`SessionManager.checkpoint()`
:param unit_list:
List of all known units. This argument is used to reconstruct the
session from a dormant state. Since the suspended data cannot
capture implementation details of each unit reliably, actual units
need to be provided externally. Unlike in :meth:`create_session()`
this list really needs to be complete, it must also include any
generated units.
:param storage:
The storage that should be used for this particular session.
The storage object holds references to existing directories
in the file system. When restoring an existing dormant session
it is important to use the correct storage object, the one that
corresponds to the file system location used be the session
before it was saved.
:ptype storage:
:class:`~plainbox.impl.session.storage.SessionStorage`
:param early_cb:
A callback that allows the caller to "see" the session object
early, before the bulk of resume operation happens. This method can
be used to register callbacks on the new session before this method
call returns. The callback accepts one argument, session, which is
being resumed. This is being passed directly to
:meth:`plainbox.impl.session.resume.SessionResumeHelper.resume()`
:param flags:
An optional set of flags that may influence the resume process.
Currently this is an internal implementation detail and no "public"
flags are provided. Passing None here is a safe equvalent of using
this API before it was introduced.
:raises:
Anything that can be raised by
:meth:`~plainbox.impl.session.storage.SessionStorage.
load_checkpoint()` and :meth:`~plainbox.impl.session.suspend.
SessionResumeHelper.resume()`
:returns:
Fresh instance of :class:`SessionManager`
"""
logger.debug("SessionManager.load_session()")
try:
data = storage.load_checkpoint()
except IOError as exc:
if exc.errno == errno.ENOENT:
state = SessionState(unit_list)
else:
raise
else:
state = SessionResumeHelper(unit_list, flags,
storage.location).resume(
data, early_cb)
context = SessionDeviceContext(state)
return cls([context], storage)
def load_session(cls, job_list, storage, early_cb=None):
"""
Open a previously checkpointed session.
This method allows one to re-open a session that was previously
created by :meth:`SessionManager.checkpoint()`
:param job_list:
List of all known jobs. This argument is used to reconstruct the
session from a dormant state. Since the suspended data cannot
capture implementation details of each job reliably actual jobs
need to be provided externally. Unlike in :meth:`create_session()`
this list really needs to be complete, it must also include
any generated jobs.
:param storage:
The storage that should be used for this particular session.
The storage object holds references to existing directories
in the file system. When restoring an existing dormant session
it is important to use the correct storage object, the one that
corresponds to the file system location used be the session
before it was saved.
:ptype storage:
:class:`~plainbox.impl.session.storage.SessionStorage`
:param early_cb:
A callback that allows the caller to "see" the session object
early, before the bulk of resume operation happens. This method can
be used to register callbacks on the new session before this method
call returns. The callback accepts one argument, session, which is
being resumed. This is being passed directly to
:meth:`plainbox.impl.session.resume.SessionResumeHelper.resume()`
:raises:
Anything that can be raised by
:meth:`~plainbox.impl.session.storage.SessionStorage.
load_checkpoint()` and :meth:`~plainbox.impl.session.suspend.
SessionResumeHelper.resume()`
:returns:
Fresh instance of :class:`SessionManager`
"""
logger.debug("SessionManager.open_session()")
data = storage.load_checkpoint()
state = SessionResumeHelper(job_list).resume(data, early_cb)
return cls(state, storage)
