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Improve exceptions and logging in ds manager

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MetricNotAvailable and NoDatasourceAvailable allow to differentiate
between having no datasources configured and a required metric being
unavailable from the datasource. Both exceptions have comments so
that the use case is clear.

The input validation of the get_backend method in the datasource
manager is improved.

Additional logging information allows to identify which metric caused
the available datasource to be discarded.

Tests are updated to validate the correct functionality of the new
exceptions.

Change-Id: I512976cce2401dbcd249d42686b78843e111a0e7
This commit is contained in:
Dantali0n
2019-05-09 17:00:06 +02:00
parent f049815cf4
commit e76c20d1c5
3 changed files with 76 additions and 29 deletions
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18
watcher/common/exception.py
View File

@@ -354,10 +354,6 @@ class IllegalArgumentException(WatcherException):
msg_fmt = _('Illegal argument')
class NoSuchMetric(WatcherException):
msg_fmt = _('No such metric')
class AuthorizationFailure(WatcherException):
msg_fmt = _('%(client)s connection failed. Reason: %(reason)s')
@@ -397,6 +393,20 @@ class DataSourceNotAvailable(WatcherException):
msg_fmt = _("Datasource %(datasource)s is not available.")
class MetricNotAvailable(WatcherException):
"""Indicate that a metric is not configured or does not exists"""
msg_fmt = _('Metric: %(metric)s not available')
class NoDatasourceAvailable(WatcherException):
"""No datasources have been configured"""
msg_fmt = _('No datasources available')
class NoSuchMetricForHost(WatcherException):
msg_fmt = _("No %(metric)s metric for %(host)s found.")
class ServiceAlreadyExists(Conflict):
msg_fmt = _("A service with name %(name)s is already working on %(host)s.")

20
watcher/datasources/manager.py
View File

@@ -87,12 +87,30 @@ class DataSourceManager(object):
self._gnocchi = gnocchi
def get_backend(self, metrics):
"""Determine the datasource to use from the configuration
Iterates over the configured datasources in order to find the first
which can support all specified metrics. Upon a missing metric the next
datasource is attempted.
"""
if not self.datasources or len(self.datasources) is 0:
raise exception.NoDatasourceAvailable
if not metrics or len(metrics) is 0:
LOG.critical("Can not retrieve datasource without specifying"
"list of required metrics.")
raise exception.InvalidParameter(parameter='metrics',
parameter_type='none empty list')
for datasource in self.datasources:
no_metric = False
for metric in metrics:
if (metric not in self.metric_map[datasource] or
self.metric_map[datasource].get(metric) is None):
no_metric = True
LOG.warning("Datasource: {0} could not be used due to"
"metric: {1}".format(datasource, metric))
break
if not no_metric:
# Try to use a specific datasource but attempt additional
@@ -103,7 +121,7 @@ class DataSourceManager(object):
return ds
except Exception:
pass
raise exception.NoSuchMetric()
raise exception.MetricNotAvailable(metric=metric)
def load_metric_map(self, file_path):
"""Load metrics from the metric_map_path"""

67
watcher/tests/datasources/test_manager.py
View File

@@ -15,6 +15,7 @@
# limitations under the License.
import mock
import six
from mock import MagicMock
@@ -38,30 +39,6 @@ class TestDataSourceManager(base.BaseTestCase):
opts.update(kwargs)
return ds_manager.DataSourceManager(**opts)
def test_get_backend(self):
manager = self._dsm()
backend = manager.get_backend(['host_cpu_usage', 'instance_cpu_usage'])
self.assertEqual(backend, manager.gnocchi)
def test_get_backend_order(self):
dss = ['monasca', 'ceilometer', 'gnocchi']
dsmcfg = self._dsm_config(datasources=dss)
manager = self._dsm(config=dsmcfg)
backend = manager.get_backend(['host_cpu_usage', 'instance_cpu_usage'])
self.assertEqual(backend, manager.monasca)
def test_get_backend_wrong_metric(self):
manager = self._dsm()
self.assertRaises(exception.NoSuchMetric, manager.get_backend,
['host_cpu', 'instance_cpu_usage'])
@mock.patch.object(gnocchi, 'GnocchiHelper')
def test_get_backend_error_datasource(self, m_gnocchi):
m_gnocchi.side_effect = exception.DataSourceNotAvailable
manager = self._dsm()
backend = manager.get_backend(['host_cpu_usage', 'instance_cpu_usage'])
self.assertEqual(backend, manager.ceilometer)
def test_metric_file_path_not_exists(self):
manager = self._dsm()
expected = ds_manager.DataSourceManager.metric_map
@@ -85,3 +62,45 @@ class TestDataSourceManager(base.BaseTestCase):
mo.return_value = {"newds": {"metric_one": "i_am_metric_one"}}
mgr = self._dsm()
self.assertNotIn('newds', mgr.metric_map.keys())
def test_get_backend(self):
manager = self._dsm()
backend = manager.get_backend(['host_cpu_usage', 'instance_cpu_usage'])
self.assertEqual(backend, manager.gnocchi)
def test_get_backend_order(self):
dss = ['monasca', 'ceilometer', 'gnocchi']
dsmcfg = self._dsm_config(datasources=dss)
manager = self._dsm(config=dsmcfg)
backend = manager.get_backend(['host_cpu_usage', 'instance_cpu_usage'])
self.assertEqual(backend, manager.monasca)
def test_get_backend_wrong_metric(self):
manager = self._dsm()
ex = self.assertRaises(
exception.MetricNotAvailable, manager.get_backend,
['host_cpu', 'instance_cpu_usage'])
self.assertIn('Metric: host_cpu not available', six.text_type(ex))
@mock.patch.object(gnocchi, 'GnocchiHelper')
def test_get_backend_error_datasource(self, m_gnocchi):
m_gnocchi.side_effect = exception.DataSourceNotAvailable
manager = self._dsm()
backend = manager.get_backend(['host_cpu_usage', 'instance_cpu_usage'])
self.assertEqual(backend, manager.ceilometer)
def test_get_backend_no_datasources(self):
dsmcfg = self._dsm_config(datasources=[])
manager = self._dsm(config=dsmcfg)
self.assertRaises(exception.NoDatasourceAvailable, manager.get_backend,
['host_cpu_usage', 'instance_cpu_usage'])
dsmcfg = self._dsm_config(datasources=None)
manager = self._dsm(config=dsmcfg)
self.assertRaises(exception.NoDatasourceAvailable, manager.get_backend,
['host_cpu_usage', 'instance_cpu_usage'])
def test_get_backend_no_metrics(self):
manager = self._dsm()
self.assertRaises(exception.InvalidParameter, manager.get_backend, [])
self.assertRaises(exception.InvalidParameter, manager.get_backend,
None)