Update normalise plugin and add README

plugins/normalise/README.md

@@ -0,0 +1,63 @@
+Normalise Plugin (Example)
+==========================
+
+This is an example plugin that demonstrates how plugins can be used
+to "normalise" alerts from different monitoring sources to ensure
+they conform to a standard before being saved to the database.
+
+Normalise actions:
+
+  * two alert attributes are checked for values and if no value is set they are assigned default values.
+  * alert text is modified to prepend the severity level in capitals.
+
+This repo should be forked or copied and the python plugin modified to suit
+the specific Alerta environment.
+
+For help, join [![Gitter chat](https://badges.gitter.im/alerta/chat.png)](https://gitter.im/alerta/chat)
+
+Installation
+------------
+
+Clone the GitHub repo and run:
+
+    $ python setup.py install
+
+Or, to install remotely from GitHub run:
+
+    $ pip install git+https://github.com/alerta/alerta-contrib.git#subdirectory=plugins/normalise
+
+Note: If Alerta is installed in a python virtual environment then plugins
+need to be installed into the same environment for Alerta to dynamically
+discover them.
+
+Configuration
+-------------
+
+Add `normalise` to the list of enabled `PLUGINS` in `alertad.conf` server
+configuration file and set plugin-specific variables either in the
+server configuration file or as environment variables.
+
+**Example**
+
+```python
+PLUGINS = ['reject','normalise']
+```
+
+Troubleshooting
+---------------
+
+Restart Alerta API and confirm that the plugin has been loaded and enabled.
+
+Set `DEBUG=True` in the `alertad.conf` configuration file and look for log
+entries similar to below:
+
+
+References
+----------
+
+  * Normalize Monitoring Traps: https://docops.ca.com/ca-service-operations-insight/3-2/en/administrating/event-management/event-management-example-scenarios/event-management-example-5-normalize-monitoring-traps
+
+License
+-------
+
+Copyright (c) 2016 Nick Satterly. Available under the MIT License.

plugins/normalise/alerta_normalise.py

@@ -11,8 +11,15 @@ class NormaliseAlert(PluginBase):
 
         LOG.info("Normalising alert...")
 
+        # prepend severity to alert text
         alert.text = '%s: %s' % (alert.severity.upper(), alert.text)
 
+        # supply different default values if missing
+        if not alert.group or alert.group == 'Misc':
+            alert.group = 'Unknown'
+        if not alert.value or alert.value == 'n/a':
+            alert.value = '--'
+
         return alert
 
     def post_receive(self, alert):