The stack trace messages about exception is not printed when the plugins are not successfully loaded

[chenying]

The stack trace messages about exception is not printed when the plugins are not successfully loaded.
Only error messages are printed. It is quite difficult to find the reason.

2016-12-08 15:29:49.265 DEBUG karbor.utils [-] Start load plugin karbor-swift-bank-plugin. from (pid=5768) load_plugin /opt/stack/karbor/karbor/utils.py:106
2016-12-08 15:29:49.269 DEBUG karbor.services.protection.client_factory [-] Found client "nova" from (pid=5768) _list_clients /opt/stack/karbor/karbor/services/protection/client_factory.py:36
2016-12-08 15:29:49.281 DEBUG karbor.services.protection.client_factory [-] Found client "cinder" from (pid=5768) _list_clients /opt/stack/karbor/karbor/services/protection/client_factory.py:36
2016-12-08 15:29:49.295 DEBUG karbor.services.protection.client_factory [-] Found client "eisoo" from (pid=5768) _list_clients /opt/stack/karbor/karbor/services/protection/client_factory.py:36
2016-12-08 15:29:49.295 ERROR karbor.services.protection.provider [-] Load bank plugin: 'karbor-swift-bank-plugin' failed. No module named abclient
2016-12-08 15:29:49.296 ERROR karbor.services.protection.provider [-] Load provider: OS Infra Provider failed. Reason: No module named abclient
2016-12-08 15:29:49.391 INFO root [-] Generating grammar tables from /usr/lib/python2.7/lib2to3/Grammar.txt
2016-12-08 15:29:49.418 INFO root [-] Generating grammar tables from /usr/lib/python2.7/lib2to3/PatternGrammar.txt

The stack trace messages is needed:

2016-12-08 15:32:27.979 WARNING stevedore.named [-] Could not load karbor.services.protection.provider.ProviderRegistry
2016-12-08 15:32:27.984 DEBUG karbor.utils [-] Start load plugin karbor-swift-bank-plugin. from (pid=6015) load_plugin /opt/stack/karbor/karbor/utils.py:106
2016-12-08 15:32:27.989 DEBUG karbor.services.protection.client_factory [-] Found client "nova" from (pid=6015) _list_clients /opt/stack/karbor/karbor/services/protection/client_factory.py:36
2016-12-08 15:32:28.002 DEBUG karbor.services.protection.client_factory [-] Found client "cinder" from (pid=6015) _list_clients /opt/stack/karbor/karbor/services/protection/client_factory.py:36
2016-12-08 15:32:28.016 DEBUG karbor.services.protection.client_factory [-] Found client "eisoo" from (pid=6015) _list_clients /opt/stack/karbor/karbor/services/protection/client_factory.py:36
2016-12-08 15:32:28.018 ERROR karbor.services.protection.provider [-] Load bank plugin: 'karbor-swift-bank-plugin' failed. No module named abclient
2016-12-08 15:32:28.018 TRACE karbor.services.protection.provider Traceback (most recent call last):
2016-12-08 15:32:28.018 TRACE karbor.services.protection.provider File "/opt/stack/karbor/karbor/services/protection/provider.py", line 116, in _load_bank
2016-12-08 15:32:28.018 TRACE karbor.services.protection.provider self._config)
2016-12-08 15:32:28.018 TRACE karbor.services.protection.provider File "/opt/stack/karbor/karbor/utils.py", line 118, in load_plugin
2016-12-08 15:32:28.018 TRACE karbor.services.protection.provider return plugin_class(*args, **kwargs)
2016-12-08 15:32:28.018 TRACE karbor.services.protection.provider File "/opt/stack/karbor/karbor/services/protection/bank_plugins/swift_bank_plugin.py", line 76, in __init__
2016-12-08 15:32:28.018 TRACE karbor.services.protection.provider self.connection = self._setup_connection()
2016-12-08 15:32:28.018 TRACE karbor.services.protection.provider File "/opt/stack/karbor/karbor/services/protection/bank_plugins/swift_bank_plugin.py", line 102, in _setup_connection
2016-12-08 15:32:28.018 TRACE karbor.services.protection.provider self._config)
2016-12-08 15:32:28.018 TRACE karbor.services.protection.provider File "/opt/stack/karbor/karbor/services/protection/client_factory.py", line 44, in create_client
2016-12-08 15:32:28.018 TRACE karbor.services.protection.provider module = importutils.import_module(module)
2016-12-08 15:32:28.018 TRACE karbor.services.protection.provider File "/usr/local/lib/python2.7/dist-packages/oslo_utils/importutils.py", line 73, in import_module
2016-12-08 15:32:28.018 TRACE karbor.services.protection.provider __import__(import_str)
2016-12-08 15:32:28.018 TRACE karbor.services.protection.provider File "/opt/stack/karbor/karbor/services/protection/clients/eisoo.py", line 21, in <module>
2016-12-08 15:32:28.018 TRACE karbor.services.protection.provider from abclient import client
2016-12-08 15:32:28.018 TRACE karbor.services.protection.provider ImportError: No module named abclient
2016-12-08 15:32:28.018 TRACE karbor.services.protection.provider
2016-12-08 15:32:28.019 ERROR karbor.services.protection.provider [-] Load provider: OS Infra Provider failed. Reason: No module named abclient
2016-12-08 15:32:28.119 INFO root [-] Generating grammar tables from /usr/lib/python2.7/lib2to3/Grammar.txt
2016-12-08 15:32:28.145 INFO root [-] Generating grammar tables from /usr/lib/python2.7/lib2to3/PatternGrammar.txt

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/408474

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/408474
Committed: https://git.openstack.org/cgit/openstack/karbor/commit/?id=42168b374fc138bb94bd1853f4814aa71b354cb9
Submitter: Jenkins
Branch: master

commit 42168b374fc138bb94bd1853f4814aa71b354cb9
Author: chenying <email address hidden>
Date: Thu Dec 8 15:53:26 2016 +0800

    Print the stack trace logs when the plugins are not successfully loaded

    Change-Id: Iad7e4c832adb9b092b7f8379fe8f8a2c1104a167
    Closes-Bug:#1648330