Fix duplication in sinks names

When we have sinks with duplicated names, problem occurs: names
conflict and we get only one measurment. This patchset will fix
it, if sinks have duplicated names, PipelineException raises.

Change-Id: I68cb3fd635b0d4cd63be9da3385cb64e0326e558
Closes-bug: 1417278

ceilometer/pipeline.py

@@ -623,8 +623,13 @@ class PipelineManager(object):
                                         cfg)
             LOG.info(_('detected decoupled pipeline config format'))
             sources = [p_type['source'](s) for s in cfg.get('sources', [])]
-            sinks = dict((s['name'], p_type['sink'](s, transformer_manager))
-                         for s in cfg.get('sinks', []))
+            sinks = {}
+            for s in cfg.get('sinks', []):
+                if s['name'] in sinks:
+                    raise PipelineException("Duplicated sink names: %s" %
+                                            s['name'], self)
+                else:
+                    sinks[s['name']] = p_type['sink'](s, transformer_manager)
             for source in sources:
                 source.check_sinks(sinks)
                 for target in source.sinks:

ceilometer/tests/test_decoupled_pipeline.py

@@ -267,3 +267,13 @@ class TestDecoupledPipeline(pipeline_base.BasePipelineTestCase):
         self._do_test_rate_of_change_in_boilerplate_pipeline_cfg(3,
                                                                  meters,
                                                                  units)
+
+    def test_duplicated_sinks_names(self):
+        self.pipeline_cfg['sinks'].append({
+            'name': 'test_sink',
+            'publishers': ['except'],
+        })
+        self.assertRaises(pipeline.PipelineException,
+                          pipeline.PipelineManager,
+                          self.pipeline_cfg,
+                          self.transformer_manager)