schema: rabbitmq queue not cleaned up upon exit

[Senthilnathan Murugappan]

Observed that schema didnt cleanup the rabbitmq queue if it fails under certain circumstances.

Traceback (most recent call last):
  File "/usr/bin/contrail-schema", line 9, in <module>
    load_entry_point('schema-transformer==0.1dev', 'console_scripts', 'contrail-schema')()
  File "/usr/lib/python2.7/dist-packages/schema_transformer/to_bgp.py", line 824, in server_main
    main()
  File "/usr/lib/python2.7/dist-packages/schema_transformer/to_bgp.py", line 818, in main
    args)
  File "/usr/lib/python2.7/dist-packages/cfgm_common/zkclient.py", line 336, in master_election
    self._election.run(func, *args, **kwargs)
  File "/usr/lib/python2.7/dist-packages/kazoo/recipe/election.py", line 48, in run
    func(*args, **kwargs)
  File "/usr/lib/python2.7/dist-packages/schema_transformer/to_bgp.py", line 799, in run_schema_transformer
    transformer = SchemaTransformer(args)
  File "/usr/lib/python2.7/dist-packages/schema_transformer/to_bgp.py", line 208, in __init__
    self._cassandra = SchemaTransformerDB(self, _zookeeper_client)
  File "/usr/lib/python2.7/dist-packages/schema_transformer/db.py", line 67, in __init__
    manager.config_log, reset_config=self._args.reset_config)
  File "/usr/lib/python2.7/dist-packages/cfgm_common/vnc_cassandra.py", line 87, in __init__
    self._cassandra_init(server_list)
  File "/usr/lib/python2.7/dist-packages/cfgm_common/vnc_cassandra.py", line 311, in _cassandra_init
    self._cassandra_init_conn_pools()
  File "/usr/lib/python2.7/dist-packages/cfgm_common/vnc_cassandra.py", line 395, in _cassandra_init_conn_pools
    write_consistency_level = wr_consistency)
  File "/usr/lib/python2.7/dist-packages/pycassa/columnfamily.py", line 284, in __init__
    self.load_schema()
  File "/usr/lib/python2.7/dist-packages/pycassa/columnfamily.py", line 312, in load_schema
    raise nfe
NotFoundException: NotFoundException(_message=None, why='Column family service_chain_uuid_table not found.')

[OpenContrail Admin (ci-admin-f)]

Review in progress for https://review.opencontrail.org/19261
Submitter: Ranjeet R (<email address hidden>)

[OpenContrail Admin (ci-admin-f)]

Reviewed: https://review.opencontrail.org/19261
Committed: http://github.org/Juniper/contrail-controller/commit/186348668ba869c9007d5e8223924afbaed525e0
Submitter: Zuul
Branch: master

commit 186348668ba869c9007d5e8223924afbaed525e0
Author: Ranjeet R <email address hidden>
Date: Tue Apr 12 18:24:23 2016 -0700

Fixes: schema: rabbitmq queue not cleaned up upon exit

If the Cassandra DB read fails/DB reinit fails
in Schema Transformer bringup, we do not perform cleanup for
the RMQ constructs created earlier. Adding exception handling
for Cassandra DB read exceptions and releasing the RMQ
constructs if it fails for some reason.

Change-Id: I3bdb78f1a6806735ad04afaf9851fa350b38f3a0
Closes-Bug: 1549949