def snapshot():
"""
Takes snapshot of the system packages. The snapshot is only a record of which packages are currently
installed. The record is kept by pisilinux history mechanism as it works automatically on install, remove
and upgrade operations.
"""
installdb = pisilinux.db.installdb.InstallDB()
historydb = pisilinux.db.historydb.HistoryDB()
historydb.create_history("snapshot")
li = installdb.list_installed()
progress = ctx.ui.Progress(len(li))
processed = 0
for name in installdb.list_installed():
package = installdb.get_package(name)
historydb.add_package(pkgBefore=package, operation="snapshot")
# Save changed config files of the package in snapshot
for f in installdb.get_files(name).list:
if f.type == "config" and pisilinux.util.config_changed(f):
fpath = pisilinux.util.join_path(ctx.config.dest_dir(), f.path)
historydb.save_config(name, fpath)
processed += 1
ctx.ui.display_progress(operation = "snapshot",
percent = progress.update(processed),
info = _("Taking snapshot of the system"))
historydb.update_history()
def takeback(operation):
"""
Takes back the system to a previous state. Uses pisilinux history to find out which packages were
installed at the time _after_ the given operation that the system is requested to be taken back.
@param operation: number of the operation that the system will be taken back -> integer
"""
historydb = pisilinux.db.historydb.HistoryDB()
historydb.create_history("takeback")
pisilinux.operations.history.takeback(operation)
