Templates for Slack notifications

This change adds an optional, user configurable template which
may be used to format the text contained in Slack notifications.

Story: 2001308
Task: 5859
Change-Id: Id936c3dc8b4f3e2430de20c8b69d0e703b1cf9ef

README.rst

@@ -131,6 +131,94 @@ StatsD server launched by monasca-agent. Default host and port points to
    -  ConfigDBTime
    -  SendNotificationTime
 
+Plugins
+-------
+
+The following notification plugins are available:
+
+- Email
+- HipChat
+- Jira
+- Pagerduty
+- Slack
+- Webhook
+
+The plugins can be configured via the Monasca Notification config file. In
+general you will need to follow these steps to enable a plugin:
+
+- Make sure that the plugin is enabled in the config file
+- Make sure that the plugin is configured in the config file
+- Restart the Monasca Notification service
+
+Slack plugin
+~~~~~~~~~~~~
+
+To use the Slack plugin you must first configure an incoming `webhook`_
+for the Slack channel you wish to post notifications to. The notification can
+then be created as follows:
+
+::
+
+    monasca notification-create slack_notification slack https://hooks.slack.com/services/MY/SECRET/WEBHOOK/URL
+
+Note that whilst it is also possible to use a token instead of a webhook,
+this approach is now `deprecated`_.
+
+By default the Slack notification will dump all available information into
+the alert. For example, a notification may be posted to Slack which looks
+like this:
+
+::
+
+    {
+      "metrics":[
+         {
+            "dimensions":{
+               "hostname":"operator"
+            },
+            "id":null,
+            "name":"cpu.user_perc"
+         }
+      ],
+      "alarm_id":"20a54a65-44b8-4ac9-a398-1f2d888827d2",
+      "state":"ALARM",
+      "alarm_timestamp":1556703552,
+      "tenant_id":"62f7a7a314904aa3ab137d569d6b4fde",
+      "old_state":"OK",
+      "alarm_description":"Dummy alarm",
+      "message":"Thresholds were exceeded for the sub-alarms: count(cpu.user_perc, deterministic) >= 1.0 with the values: [1.0]",
+      "alarm_definition_id":"78ce7b53-f7e6-4b51-88d0-cb741e7dc906",
+      "alarm_name":"dummy_alarm"
+    }
+
+The format of the above message can be customised with a Jinja template. All fields
+from the raw Slack message are available in the template. For example, you may
+configure the plugin as follows:
+
+::
+
+    [notification_types]
+    enabled = slack
+
+    [slack_notifier]
+    message_template = /etc/monasca/slack_template.j2
+    timeout = 10
+    ca_certs = /etc/ssl/certs/ca-bundle.crt
+    insecure = False
+
+With the following contents of `/etc/monasca/slack_template.j2`:
+
+::
+
+    {{ alarm_name }} has triggered on {% for item in metrics %}host {{ item.dimensions.hostname }}{% if not loop.last %}, {% endif %}{% endfor %}.
+
+With this configuration, the raw Slack message above would be transformed
+into:
+
+::
+
+   dummy_alarm has triggered on host(s): operator.
+
 Future Considerations
 =====================
 
@@ -146,3 +234,7 @@ Future Considerations
      NotificationEngine instance using webhooks to a local http server. Is
      that fast enough?
    - Are we putting too much load on Kafka at ~200 commits per second?
+
+.. _webhook: https://api.slack.com/incoming-webhooks
+
+.. _deprecated: https://api.slack.com/custom-integrations/legacy-tokens

monasca_notification/plugins/slack_notifier.py

@@ -14,11 +14,13 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import os
 import requests
 from six.moves import urllib
 import ujson as json
 
 from debtcollector import removals
+import jinja2
 from oslo_config import cfg
 
 from monasca_notification.plugins import abstract_notifier
@@ -86,10 +88,19 @@ class SlackNotifier(abstract_notifier.AbstractNotifier):
                 'metrics': notification.metrics}
 
         slack_request = {}
-        slack_request['text'] = json.dumps(body, indent=3)
+        if CONF.slack_notifier.message_template:
+            slack_request['text'] = self._render_message_template(body)
+        else:
+            slack_request['text'] = json.dumps(body, indent=3)
 
         return slack_request
 
+    def _render_message_template(self, params):
+        path, name = os.path.split(CONF.slack_notifier.message_template)
+        loader = jinja2.FileSystemLoader(path)
+        env = jinja2.Environment(loader=loader, autoescape=True)
+        return env.get_template(name).render(params)
+
     def _check_response(self, result):
         if 'application/json' in result.headers.get('Content-Type'):
             response = result.json()
@@ -192,7 +203,8 @@ slack_notifier_opts = [
     cfg.IntOpt(name='timeout', default=5, min=1),
     cfg.BoolOpt(name='insecure', default=True),
     cfg.StrOpt(name='ca_certs', default=None),
-    cfg.StrOpt(name='proxy', default=None)
+    cfg.StrOpt(name='proxy', default=None),
+    cfg.StrOpt(name='message_template', default=None)
 ]
 
 

tests/resources/test_slackformat.template

@@ -0,0 +1 @@
+{{ alarm_name }} has triggered on {% for item in metrics %}host {{ metrics[0].dimensions.hostname }}, service {{ item.dimensions.service }}{% if not loop.last %}, {% endif %}{% endfor %}.

tests/test_slack_notification.py

@@ -110,6 +110,15 @@ class TestSlack(base.PluginTestCase):
     def _validate_post_args(self, post_args, data_format):
         self.assertEqual(slack_text(),
                          json.loads(post_args.get(data_format).get('text')))
+        self._validate_post_args_base(post_args)
+
+    def _validate_templated_post_args(self, post_args, data_format,
+                                      expected_slack_text):
+        self.assertEqual(expected_slack_text,
+                         post_args.get(data_format).get('text'))
+        self._validate_post_args_base(post_args)
+
+    def _validate_post_args_base(self, post_args):
         self.assertEqual({'https': 'http://yourid:password@proxyserver:8080'},
                          post_args.get('proxies'))
         self.assertEqual(50, post_args.get('timeout'))
@@ -128,6 +137,24 @@ class TestSlack(base.PluginTestCase):
         self._validate_post_args(mock_method.call_args_list[0][1], 'json')
         self.assertEqual([], slack_notifier.SlackNotifier._raw_data_url_caches)
 
+    def test_templated_slack_webhook_success(self):
+        """A templated message is successfully sent as json
+        """
+        self.conf_override(
+            message_template='tests/resources/test_slackformat.template',
+            group='slack_notifier'
+        )
+        response_list = [RequestsResponse(200, 'ok',
+                                          {'Content-Type': 'application/text'})]
+        mock_method, result = self._notify(response_list)
+        self.assertTrue(result)
+        mock_method.assert_called_once()
+        expected_text = 'test Alarm has triggered on host foo1, service bar1.'
+        self._validate_templated_post_args(mock_method.call_args_list[0][1],
+                                           'json',
+                                           expected_text)
+        self.assertEqual([], slack_notifier.SlackNotifier._raw_data_url_caches)
+
     def test_slack_webhook_fail(self):
         """data is sent twice as json and raw data, and slack returns failure for
            both requests