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.TH "FirstAidKit Backup system" "1"
.SH "NAME" firstaidkit-backup
.BR
.SH "DESCRIPTION"
To abstract the plugin developer from lowlevel backup logic, the
plugins utilize backup object named self._backups. Developer can use
it to backup and restore files and arbitrary chunks of data.
The backup system si also thread safe and ensures integrity of the backups,
so the developer does not have to care about locks and synchronization.
.SH "Requesting a backup storage space"
Every plugin has access to self._backups attribute, which is the reference
to master backup system instance. Using this attribute to obtain dedicated
backup space for the plugin is easy. Just type:
self.mybackupspace = self._backups.getBackup(someuniquename)
After all work is done, free the storage space using:
self._backups.getBackup.closeBackup(someuniquename)
.SH "Using the backup space instance"
The instance of backup space then gives the plugin access to several methods:
.IP "backupPath(self, path, name = None)"
Copy the file or directory specified by path do the backup storage and give it the specified name.
The name equals to the path by default.
.IP "backupValue(self, value, name)"
This method makes possible to save arbitrary chunk of data under specified name.
.IP "restoreName(self, name, path = None)"
Restore backup object specified by it's name to it's original location or to the path if specified.
.IP "restorePath(self, path, name = None)"
Restore backup object which resided at specified path to it's own original location. If the name is specified,
use the object with that name and restore it to the path.
.IP "restoreValue(self, name)"
Get the data saved under the name from backup storage.
.IP "delete(self, name)"
Delete backup object with specified name.
.IP "cleanup(self)"
Cleanup the backup storage space. You shouldn't use this method, the backup system takes care about it.
.SH "Persistent backup storage space"
The idea to have a backup space is to use it when the plugin is running or to
have it when firstaidkit has an unrecoverable error and must bail. But when
all went well, firstaidkit deleted all the backups. The question arose of what
to do when the user wanted to revert the changes to whatever the plugins had
done to the system. This had to be possible, specially with plugins like grub
that have the potential of making the system unbootable. The answer to this
question came in the form of the persistent backups.
.IP "Specifying persistent storage"
A persistent backup will not be deleted at the end of the plugin execution.
It will persiste in the storage directory untill the user decides to delte
it. Firstaidkit will tell the user the dir name when it ends execution.
To use a persistent the developer must specify when calling the backup space
that it must be persistent. This is done by passing persistent=True when
creating the object.
.IP "Naming persistent storage"
For the revert feature to work the backup directory must be named in a
unique form. This is necesarry to correctly identify the backup dir related to
the plugin when doing a revert. You can use the plugin module name for this.
Not the complete module name, because the preceding submodules before the
actuall plugin module name might change between pytho virtual machine calls.
To accomplish this, pass "self.__module__.split('.')[-1:][0]" as the first
argument of getBackup() call.
If you think that the latter is a little bit too much black magic for you,
you can also name the backup storage with a string of your preference. But
you must implement a function called getBackupId(). This function will return
the name that you gave the persistent backup storage. In other words, this
will return whatever you passed to getBackup()
.IP "Additional info"
For the persistent backup storage to be used, the developer must add a revert
function to the plugin. This is the function that will be called when the
persistent backup storage is used.
.PP
.SH "Developing another backup storage backend"
.SH "SEE ALSO"
firstaidkit-plugin
firstaidkit-reporting
http://fedorahosted.org/firstaidkit
.SH "AUTHORS"
Martin Sivak <msivak@redhat.com>
Joel Granados <jgranado@redhat.com>
.SH "BUGS"
Please search/report bugs at http://fedorahosted.org/firstaidkit/newticket
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