Add a service check for Couchbase.

- With a test that should work without Couchbase running (testing
  failure)
- Also cleaned up some pre-omnibus code checking the Python version.

checks.d/couchbase.py

@@ -18,6 +18,7 @@ class Couchbase(AgentCheck):
     """Extracts stats from Couchbase via its REST API
     http://docs.couchbase.com/couchbase-manual-2.0/#using-the-rest-api
     """
+    SERVICE_CHECK_NAME = 'couchbase.can_connect'
 
     def _create_metrics(self, data, tags=None):
         storage_totals = data['stats']['storageTotals']
@@ -45,18 +46,14 @@ def _create_metrics(self, data, tags=None):
 
 
     def _get_stats(self, url, instance):
-        "Hit a given URL and return the parsed json"
+        """ Hit a given URL and return the parsed json. """
         self.log.debug('Fetching Couchbase stats at url: %s' % url)
         req = urllib2.Request(url, None, headers(self.agentConfig))
         if 'user' in instance and 'password' in instance:
             add_basic_auth(req, instance['user'], instance['password'])
 
-        if instance['is_recent_python']:
-            timeout = instance.get('timeout' , DEFAULT_TIMEOUT)
-            request = urllib2.urlopen(req,timeout=timeout)
-        else:
-            request = urllib2.urlopen(req)
-
+        timeout = float(instance.get('timeout', DEFAULT_TIMEOUT))
+        request = urllib2.urlopen(req, timeout=timeout)
         response = request.read()
         return json.loads(response)
 
@@ -72,7 +69,6 @@ def check(self, instance):
         else:
             tags = list(set(tags))
         tags.append('instance:%s' % server)
-        instance['is_recent_python'] = sys.version_info >= (2,6,0)
         data = self.get_data(server, instance)
         self._create_metrics(data, tags=list(set(tags)))
 
@@ -85,12 +81,25 @@ def get_data(self, server, instance):
 
         # build couchbase stats entry point
         url = '%s%s' % (server, COUCHBASE_STATS_PATH)
-        overall_stats = self._get_stats(url, instance)
 
-        # No overall stats? bail out now
-        if overall_stats is None:
-            raise Exception("No data returned from couchbase endpoint: %s" % url)
-
+        # Fetch initial stats and capture a service check based on response.
+        service_check_tags = {'instance:%s' % server}
+        try:
+            overall_stats = self._get_stats(url, instance)
+            # No overall stats? bail out now
+            if overall_stats is None:
+                raise Exception("No data returned from couchbase endpoint: %s" % url)
+        except urllib2.URLError as e:
+            self.service_check(self.SERVICE_CHECK_NAME, AgentCheck.CRITICAL,
+                tags=service_check_tags, message=e.reason)
+            raise
+        except Exception as e:
+            self.service_check(self.SERVICE_CHECK_NAME, AgentCheck.CRITICAL,
+                tags=service_check_tags, message=str(e))
+            raise
+        else:
+            self.service_check(self.SERVICE_CHECK_NAME, AgentCheck.OK)
+
         couchbase['stats'] = overall_stats
 
         nodes = overall_stats['nodes']
@@ -130,7 +139,7 @@ def camel_case_to_joined_lower(self, variable):
 
         # remove duplicate _
         converted_variable = re.sub('_+', '_', converted_variable)
-        
+
         # handle special case of starting/ending underscores
         converted_variable = re.sub('^_|_$', '', converted_variable)
 

tests/test_couchbase.py

@@ -1,8 +1,11 @@
 import unittest
 from tests.common import load_check
+from checks import AgentCheck
 
 from nose.plugins.attrib import attr
 from nose.plugins.skip import SkipTest
+
+@attr('couchbase')
 class CouchbaseTestCase(unittest.TestCase):
 
     def setUp(self):
@@ -11,6 +14,7 @@ def setUp(self):
                 'server': 'http://localhost:8091',
                 'user': 'Administrator',
                 'password': 'password',
+                'timeout': 0.1
             }]
         }
         self.agentConfig = {
@@ -19,7 +23,6 @@ def setUp(self):
         }
         self.check = load_check('couchbase', self.config, self.agentConfig)
 
-    @attr('couchbase')
     def test_camel_case_to_joined_lower(self):
         test_pairs = {
             'camelCase' : 'camel_case',
@@ -36,17 +39,16 @@ def test_camel_case_to_joined_lower(self):
 
         for test_input, expected_output in test_pairs.items():
             test_output = self.check.camel_case_to_joined_lower(test_input)
-            self.assertEqual(test_output, expected_output, 
+            self.assertEqual(test_output, expected_output,
                 'Input was %s, expected output was %s, actual output was %s' % (test_input, expected_output, test_output))
 
-    @attr('couchbase')
     def test_metrics_casing(self):
         raise SkipTest("Skipped for now as it's hard to configure couchbase on travis")
         self.check.check(self.config['instances'][0])
 
         metrics = self.check.get_metrics()
 
-        camel_cased_metrics = [u'couchbase.hdd.used_by_data', 
+        camel_cased_metrics = [u'couchbase.hdd.used_by_data',
             u'couchbase.ram.used_by_data',
             u'couchbase.ram.quota_total',
             u'couchbase.ram.quota_used',
@@ -55,7 +57,6 @@ def test_metrics_casing(self):
         found_metrics = [k[0] for k in metrics if k[0] in camel_cased_metrics]
         self.assertEqual(found_metrics.sort(), camel_cased_metrics.sort())
 
-    @attr('couchbase')
     def test_metrics(self):
         raise SkipTest("Skipped for now as it's hard to configure couchbase on travis")
         self.check.check(self.config['instances'][0])
@@ -68,3 +69,15 @@ def test_metrics(self):
 
         self.assertTrue(len([k for k in metrics if -1 != k[0].find('by_node')]) > 1, 'Unable to fund any per node metrics')
         self.assertTrue(len([k for k in metrics if -1 != k[0].find('by_bucket')]) > 1, 'Unable to fund any per node metrics')
+
+    def test_service_check(self):
+        try:
+            self.check.check(self.config['instances'][0])
+        except Exception:
+            service_checks = self.check.get_service_checks()
+            self.assertEqual(len(service_checks), 1)
+            service_check = service_checks[0]
+            self.assertEqual(service_check['check'], self.check.SERVICE_CHECK_NAME)
+            self.assertEqual(service_check['status'], AgentCheck.CRITICAL)
+        else:
+            raise Exception('Couchbase check should have failed')