Support automatic db creation for InfluxDB

At the moment, monasca persister assumes that an InfluxDB database
already exists. With this change, a new database is created when it does
not exist.

Story: 2006331
Task: 37327

Change-Id: I3d88eb8b2cdbd81f9c84fe1703b2ee2d1b09e1ab

monasca_persister/repositories/influxdb/abstract_repository.py

@@ -57,8 +57,9 @@ class AbstractInfluxdbRepository(abstract_repository.AbstractRepository):
                                                    database=database)
                 break
             except influxdb.exceptions.InfluxDBClientError as ex:
-                if (str(ex).startswith(DATABASE_NOT_FOUND_MSG) and
-                        self.conf.influxdb.db_per_tenant):
+                # When a databse is not found, the returned exception resolves
+                # to: {"error":"database not found: \"test\""}
+                if DATABASE_NOT_FOUND_MSG in str(ex):
                     self._influxdb_client.create_database(database)
                 else:
                     raise

monasca_persister/tests/test_influxdb_metrics_repository.py

@@ -13,14 +13,22 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import influxdb
+from influxdb.exceptions import InfluxDBClientError
+
 from mock import Mock
 from mock import patch
+from mock import call
+
+from monasca_persister.repositories.influxdb.metrics_repository import MetricInfluxdbRepository
 
 from oslotest import base
 from oslo_config import cfg
 
-from monasca_persister.repositories.influxdb.metrics_repository import MetricInfluxdbRepository
+import six
 
+db_not_found = InfluxDBClientError(
+    content='{"error": "database not found: db"}', code=404)
 
 class TestMetricInfluxdbRepository(base.BaseTestCase):
 
@@ -30,13 +38,46 @@ class TestMetricInfluxdbRepository(base.BaseTestCase):
     def tearDown(self):
         super(TestMetricInfluxdbRepository, self).tearDown()
 
-    def test_process_message(self):
-        metric = self._get_metric()
-        with patch.object(cfg, 'CONF', return_value=None):
-            metric_repo = MetricInfluxdbRepository()
-            self.assertIsInstance(metric_repo.process_message(metric), tuple)
+    def _test_process_message(self, metrics_repo, data_points, metric, tenant):
+        _dp, _tenant = metrics_repo.process_message(metric)
+        self.assertIsInstance(_dp, six.string_types)
+        self.assertEqual(_tenant, tenant)
+        data_points.append(_tenant, _dp)
 
-    def _get_metric(self):
+    @patch.object(influxdb, 'InfluxDBClient')
+    @patch.object(cfg, 'CONF', return_value=None)
+    def _test_write_batch(self, mock_conf, mock_influxdb_client,
+                          db_per_tenant, db_exists):
+        mock_conf.influxdb.database_name = db_name = 'db'
+        mock_conf.influxdb.db_per_tenant = db_per_tenant
+        t1 = u'fake_tenant_id_1'
+        t2 = u'fake_tenant_id_2'
+        m1 = self._get_metric(t1)
+        m2 = self._get_metric(t2)
+        metrics_repo = MetricInfluxdbRepository()
+        data_points = metrics_repo.data_points_class()
+        self._test_process_message(metrics_repo, data_points, m1, t1)
+        self._test_process_message(metrics_repo, data_points, m2, t2)
+        metrics_repo._influxdb_client = mock_influxdb_client
+        if db_exists:
+            metrics_repo._influxdb_client.write_points = Mock()
+        else:
+            metrics_repo._influxdb_client.write_points = Mock(
+                side_effect=[db_not_found, None, db_not_found, None])
+            if db_per_tenant:
+                call1 = call('%s_%s' % (db_name, t1))
+                call2 = call('%s_%s' % (db_name, t2))
+                calls = [call1, call2]
+            else:
+                calls = [call(db_name)]
+        metrics_repo.write_batch(data_points)
+        if db_exists:
+            mock_influxdb_client.create_database.assert_not_called()
+        else:
+            mock_influxdb_client.create_database.assert_has_calls(
+                calls, any_order=True)
+
+    def _get_metric(self, tenant_id):
         metric = '''
             {
               "metric":
@@ -54,7 +95,7 @@ class TestMetricInfluxdbRepository(base.BaseTestCase):
                 "meta":
                 {
                   "region":"RegionOne",
-                  "tenantId":"df4c002353de4399b92fa79d8374819b"
+                  "tenantId":"''' + tenant_id + '''"
                 },
                 "creation_time":1554725988
             }
@@ -62,3 +103,15 @@ class TestMetricInfluxdbRepository(base.BaseTestCase):
         message = Mock()
         message.value.return_value = metric
         return message
+
+    def test_write_batch_db_exists(self):
+        self._test_write_batch(db_per_tenant=False, db_exists=True)
+
+    def test_write_batch(self):
+        self._test_write_batch(db_per_tenant=False, db_exists=False)
+
+    def test_write_batch_db_per_tenant_db_exists(self):
+        self._test_write_batch(db_per_tenant=True, db_exists=True)
+
+    def test_write_batch_db_per_tenant(self):
+        self._test_write_batch(db_per_tenant=True, db_exists=False)

releasenotes/notes/support-automatic-db-creation-0856216b42b91e7d.yaml

@@ -0,0 +1,4 @@
+---
+features:
+  - |
+    Support for automatic database creation in InfluxDB has been added.