Check the namespaces duplication for ceilometer-polling

This change add validation for the namespaces duplication when launch
a ceilometer-polling service with duplicated namespaces specified by
--polling-namespaces option.

Change-Id: Iacd80b77bda4ae16d0307ebed6aa9903204c94d2
Closes-Bug: #1428476

ceilometer/cmd/polling.py

@@ -17,16 +17,20 @@
 from oslo_config import cfg
 
 from ceilometer.agent import manager
+from ceilometer.i18n import _LW
+from ceilometer.openstack.common import log
 from ceilometer.openstack.common import service as os_service
 from ceilometer import service
 
+LOG = log.getLogger(__name__)
+
 CONF = cfg.CONF
 
 
 class MultiChoicesOpt(cfg.Opt):
     def __init__(self, name, choices=None, **kwargs):
         super(MultiChoicesOpt, self).__init__(name,
-                                              type=cfg.types.List(),
+                                              type=DeduplicatedCfgList(),
                                               **kwargs)
         self.choices = choices
 
@@ -39,6 +43,17 @@ class MultiChoicesOpt(cfg.Opt):
             kwargs['choices'] = choices
         return kwargs
 
+
+class DeduplicatedCfgList(cfg.types.List):
+    def __call__(self, *args, **kwargs):
+        result = super(DeduplicatedCfgList, self).__call__(*args, **kwargs)
+        if len(result) != len(set(result)):
+            LOG.warning(_LW("Duplicated values: %s found in CLI options, "
+                            "auto de-duplidated"), result)
+            result = list(set(result))
+        return result
+
+
 CLI_OPTS = [
     MultiChoicesOpt('polling-namespaces',
                     default=['compute', 'central'],

ceilometer/tests/test_bin.py

@@ -211,3 +211,33 @@ class BinApiTestCase(base.BaseTestCase):
         response, content = self.get_response('v2/meters')
         self.assertEqual(200, response.status)
         self.assertEqual([], json.loads(content))
+
+
+class BinCeilometerPollingServiceTestCase(base.BaseTestCase):
+    def setUp(self):
+        super(BinCeilometerPollingServiceTestCase, self).setUp()
+        content = ("[DEFAULT]\n"
+                   "rpc_backend=fake\n"
+                   "[database]\n"
+                   "connection=log://localhost\n")
+        self.tempfile = fileutils.write_to_tempfile(content=content,
+                                                    prefix='ceilometer',
+                                                    suffix='.conf')
+        self.subp = None
+
+    def tearDown(self):
+        super(BinCeilometerPollingServiceTestCase, self).tearDown()
+        if self.subp:
+            self.subp.kill()
+        os.remove(self.tempfile)
+
+    def test_starting_with_duplication_namespaces(self):
+        self.subp = subprocess.Popen(['ceilometer-polling',
+                                      "--config-file=%s" % self.tempfile,
+                                      "--polling-namespaces",
+                                      "compute",
+                                      "compute"],
+                                     stderr=subprocess.PIPE)
+        out = self.subp.stderr.read(1024)
+        self.assertIn('Duplicated values: [\'compute\', \'compute\'] '
+                      'found in CLI options, auto de-duplidated', out)