NDB objects

Start

In the simplest case to start the DB is as easy as:

ndb = NDB()

There are several debug options that may be useful:

  • log=<spec> -- controls the logging

  • rtnl_debug=<True|False> -- create and use log tables to store RTNL events

  • libc=<obj> -- NDB doesn't use libc, but may pass it to RTNL sources

  • sources={<spec>} -- RTNL sources to use

  • db_provider=<spec> -- which DB backend to use

  • db_spec=<spec> -- this spec will be passed to the DB provider

  • db_cleanup=<True|False> -- cleanup the DB upon exit

  • auto_netns=<True|False> -- [experimental] discover and connect to netns

Some options explained:

log

The simplest is log='on', it turns on stdio logging on the default level. To force the debug level, use log='debug'.

More log alternatives: Debug and logging

db_cleanup

Default is True. Setting this to False forces NDB to leave the data in the connected database upon exit. This may have side effects on the next start, use it only for debug purposes.

rtnl_debug

This option tells NDB if it must create and use the log tables. Normally all the incoming events become aggregated, thus RTM_NEWLINK + RTM_DELLINK will result in zero records -- an interface was created, destroyed and removed from the database.

But in the log tables all the records will be stored, so it is what it looks like -- the events log. The log tables are not used to create objects, they are not rotated. Use this option with caution.

To review the event logs use SQL or ndb.schema.export()

See also: Debug and logging

sources

::
>>> sources = [{'netns': 'test01'},
               {'netns': 'test02'},
               {'target': 'localhost', 'kind': 'local'}]
>>> ndb = NDB(log='on', sources=sources)
2020-03-24 18:01:48,241    DEBUG pyroute2.ndb.139900805197264.sources.test01: init
2020-03-24 18:01:48,242    DEBUG pyroute2.ndb.139900805197264.sources.test01: starting the source
2020-03-24 18:01:48,242    DEBUG pyroute2.ndb.139900805197264.sources.test02: init
2020-03-24 18:01:48,243    DEBUG pyroute2.ndb.139900805197264.sources.test01: connecting
2020-03-24 18:01:48,248    DEBUG pyroute2.ndb.139900805197264.sources.test02: starting the source
2020-03-24 18:01:48,249    DEBUG pyroute2.ndb.139900805197264.sources.localhost: init
2020-03-24 18:01:48,250    DEBUG pyroute2.ndb.139900805197264.sources.test02: connecting
2020-03-24 18:01:48,256    DEBUG pyroute2.ndb.139900805197264.sources.localhost: starting the source
2020-03-24 18:01:48,259    DEBUG pyroute2.ndb.139900805197264.sources.localhost: connecting
2020-03-24 18:01:48,262    DEBUG pyroute2.ndb.139900805197264.sources.localhost: loading
2020-03-24 18:01:48,265    DEBUG pyroute2.ndb.139900805197264.sources.test01: loading
2020-03-24 18:01:48,278    DEBUG pyroute2.ndb.139900805197264.sources.test02: loading
2020-03-24 18:01:48,478    DEBUG pyroute2.ndb.139900805197264.sources.localhost: running
2020-03-24 18:01:48,499    DEBUG pyroute2.ndb.139900805197264.sources.test01: running
2020-03-24 18:01:48,537    DEBUG pyroute2.ndb.139900805197264.sources.test02: running

The RTNL sources documenation: RTNL sources

db_provider, db_spec

::
>>> ndb_fs = NDB(db_provider='sqlite3', db_spec='test.db')
...
$ echo 'select f_ifla_ifname from interfaces' | sqlite3 test.db
lo
enp0s31f6
wlp58s0
virbr0
virbr0-nic
...

The database backend options: Database

Stop

In order to get all the pending calls finished and synchronized, it is a good idea to explicitly close and stop the DB:

ndb = NDB()
...
ndb.close()

NDB objects also support the context manager protocol:

with NDB() as ndb:
    ...
    ...
#
# ---> <--- here the NDB instance will be synchronized and stopped