Add contrail_ifmap_age plugin

Closes-Bug: PROD-15501

Change-Id: I3cea3b8670eecb1c3aba879f7383cad3d13d4ab9
diff --git a/collectd/files/plugin/contrail_ifmap_age.py b/collectd/files/plugin/contrail_ifmap_age.py
new file mode 100644
index 0000000..78a4cef
--- /dev/null
+++ b/collectd/files/plugin/contrail_ifmap_age.py
@@ -0,0 +1,105 @@
+#!/usr/bin/python
+# Copyright 2017 Mirantis, Inc.
+#
+# 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 a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import contextlib
+import time
+import urllib2
+from xml.etree import ElementTree
+if __name__ == '__main__':
+    import collectd_fake as collectd
+else:
+    import collectd
+import collectd_base as base
+
+
+NAME = 'contrail_ifmap_age'
+
+
+class ContrailIfmapTraceBufPlugin(base.Base):
+    """
+    This plugin checks age of last entry in IF-MAP trace buffer.
+    The idea is to collect the ages of last entry in IF-MAP trace buffer over
+    multiple nodes and check statistical properties of the set to
+    determine incorrectly functioning irond IF-MAP server.
+    """
+    def __init__(self, *args, **kwargs):
+        super(ContrailIfmapTraceBufPlugin, self).__init__(*args, **kwargs)
+        self.plugin = NAME
+        self.port = 8083
+        self.host = 'localhost'
+        self.protocol = 'http'
+
+    def config_callback(self, conf):
+        super(ContrailIfmapTraceBufPlugin, self).config_callback(conf)
+
+        for node in conf.children:
+            if node.key == 'port':
+                self.port = node.values[0]
+            elif node.key == 'host':
+                self.host = node.values[0]
+            elif node.key == 'protocol':
+                self.protocol = node.values[0]
+
+    def itermetrics(self):
+        url = "{}://{}:{}/Snh_SandeshTraceRequest?x=IFMapTraceBuf".format(
+            self.protocol, self.host, self.port)
+        try:
+            with contextlib.closing(urllib2.urlopen(url, None, 5)) as response:
+                rcode = response.getcode()
+                if rcode == 200:
+                    tree = ElementTree.fromstring(response.read())
+                    items = [(int(exc.text.split()[0]), exc.text)
+                             for exc in tree.iter('element')]
+                    if len(items) > 0:
+                        last_entry = sorted(items, reverse=True)[0][0]
+                        now = time.time()
+                        age = now - last_entry / 1000000.0
+                        msg = "The last entry is {} seconds old."
+                        self.logger.info(msg.format(age))
+                        yield {'values': age, 'type': 'gauge'}
+                    else:
+                        msg = "No entry in IF-MAP trace buffer!"
+                        raise base.CheckException(msg)
+                else:
+                    msg = "Unexpected code {} while contacting {}"
+                    raise base.CheckException(msg.format(rcode, url))
+        except urllib2.URLError as exc:
+            msg = "Cannot retrieve last entry from IF-MAP trace buffer: {}!"
+            raise base.CheckException(msg.format(str(exc)))
+
+
+plugin = ContrailIfmapTraceBufPlugin(collectd)
+
+
+def config_callback(conf):
+    """
+        Collectd callback for configuration
+    """
+    plugin.config_callback(conf)
+
+
+def read_callback():
+    """
+        Collectd callback for reading metrics
+    """
+    plugin.read_callback()
+
+
+if __name__ == '__main__':
+    collectd.load_configuration(plugin)
+    plugin.read_callback()
+else:
+    collectd.register_config(config_callback)
+    collectd.register_read(read_callback)