Merge "Remove required healthcheck import of cassandra"

monasca_api/healthcheck/metrics_db_check.py

@@ -1,4 +1,5 @@
 # Copyright 2017 FUJITSU LIMITED
+# (C) Copyright 2017 Hewlett Packard Enterprise Development LP
 #
 # Licensed under the Apache License, Version 2.0 (the "License"); you may
 # not use this file except in compliance with the License. You may obtain
@@ -14,9 +15,9 @@
 
 import requests
 
-from cassandra import cluster
 from oslo_config import cfg
 from oslo_log import log
+from oslo_utils import importutils
 
 from monasca_api.common.repositories import exceptions
 from monasca_api.healthcheck import base
@@ -42,11 +43,19 @@ class MetricsDbCheck(base.BaseHealthCheck):
     Otherwise unhealthy status is returned with explanation.
     """
 
-    def health_check(self):
+    def __init__(self):
+        # Try to import cassandra. Not a problem if it can't be imported as long
+        # as the metrics db is influx
+        self._cluster = importutils.try_import('cassandra.cluster', None)
         metric_driver = CONF.repositories.metrics_driver
-        db = self._detected_database_type(metric_driver)
+        self._db = self._detected_database_type(metric_driver)
+        if self._db == 'cassandra' and self._cluster is None:
+            # Should not happen, but log if it does somehow
+            LOG.error("Metrics Database is Cassandra but cassandra.cluster"
+                      "not importable. Unable to do health check")
 
-        if db == 'influxdb':
+    def health_check(self):
+        if self._db == 'influxdb':
             status = self._check_influxdb_status()
         else:
             status = self._check_cassandra_status()
@@ -63,8 +72,7 @@ class MetricsDbCheck(base.BaseHealthCheck):
             raise exceptions.UnsupportedDriverException(
                 'Driver {0} is not supported by Healthcheck'.format(driver))
 
-    @staticmethod
-    def _check_influxdb_status():
+    def _check_influxdb_status(self):
         uri = 'http://{0}:{1}/ping'.format(CONF.influxdb.ip_address,
                                            CONF.influxdb.port)
         try:
@@ -75,10 +83,11 @@ class MetricsDbCheck(base.BaseHealthCheck):
         return resp.ok, 'OK' if resp.ok else 'Error: {0}'.format(
             resp.status_code)
 
-    @staticmethod
-    def _check_cassandra_status():
+    def _check_cassandra_status(self):
+        if self._cluster is None:
+            return False, "Cassandra driver not imported"
         try:
-            cassandra = cluster.Cluster(
+            cassandra = self._cluster.Cluster(
                 CONF.cassandra.cluster_ip_addresses.split(',')
             )
             session = cassandra.connect(CONF.cassandra.keyspace)

monasca_api/tests/test_metrics_db_health_check.py

@@ -1,4 +1,5 @@
 # Copyright 2017 FUJITSU LIMITED
+# (C) Copyright 2017 Hewlett Packard Enterprise Development LP
 #
 # Licensed under the Apache License, Version 2.0 (the "License"); you may
 # not use this file except in compliance with the License. You may obtain
@@ -147,8 +148,8 @@ class TestMetricsDbHealthCheck(base.BaseTestCase):
         self.assertTrue(result.healthy)
         self.assertEqual('OK', result.message)
 
-    @mock.patch('monasca_api.healthcheck.metrics_db_check.cluster.Cluster')
-    def test_should_fail_cassandra_unavailable(self, cluster):
+    @mock.patch('monasca_api.healthcheck.metrics_db_check.importutils.try_import')
+    def test_should_fail_cassandra_unavailable(self, try_import):
         messaging_conf = {
             'metrics_driver': 'cassandra.metrics_repository:MetricsRepository'
         }
@@ -159,17 +160,40 @@ class TestMetricsDbHealthCheck(base.BaseTestCase):
         self._conf.config(group='repositories', **messaging_conf)
         self._conf.config(group='cassandra', **cassandra_conf)
 
+        cluster = mock.Mock()
         cas_mock = mock.Mock()
-        cluster.side_effect = cl.NoHostAvailable(message='Host unavailable',
-                                                 errors='Unavailable')
-        cluster.return_value = cas_mock
+        cas_mock.side_effect = cl.NoHostAvailable(message='Host unavailable',
+                                                  errors='Unavailable')
+        cluster.Cluster = cas_mock
+        try_import.return_value = cluster
 
         db_health = tdc.MetricsDbCheck()
         result = db_health.health_check()
 
         self.assertFalse(result.healthy)
 
-    @mock.patch('monasca_api.healthcheck.metrics_db_check.cluster.Cluster')
+    @mock.patch('monasca_api.healthcheck.metrics_db_check.importutils.try_import')
+    def test_should_fail_cassandra_no_driver(self, try_import):
+        messaging_conf = {
+            'metrics_driver': 'cassandra.metrics_repository:MetricsRepository'
+        }
+        cassandra_conf = {
+            'cluster_ip_addresses': 'localhost',
+            'keyspace': 'test'
+        }
+        self._conf.config(group='repositories', **messaging_conf)
+        self._conf.config(group='cassandra', **cassandra_conf)
+
+        # Simulate cassandra driver not available
+        try_import.return_value = None
+
+        db_health = tdc.MetricsDbCheck()
+        db_health.cluster = None
+        result = db_health.health_check()
+
+        self.assertFalse(result.healthy)
+
+    @mock.patch('monasca_api.healthcheck.metrics_db_check.importutils.try_import')
     def test_should_pass_cassandra_is_available(self, _):
         messaging_conf = {
             'metrics_driver': 'cassandra.metrics_repository:MetricsRepository'