Add a publisher for MQTT

Add support for the MQTT Notification Plugin
(https://wiki.jenkins-ci.org/display/JENKINS/MQTT+Notification+Plugin)

Change-Id: Ibe867a15f5621601a45c2e1d6281f4db67df29d7

jenkins_jobs/modules/publishers.py

@@ -300,6 +300,52 @@ def campfire(registry, xml_parent, data):
         XML.SubElement(room, 'campfire reference="../../campfire"')
 
 
+def mqtt(registry, xml_parent, data):
+    """yaml: mqtt
+    This plugin lets you send build notifications to a MQTT message queue.
+    Requires the :jenkins-wiki:`MQTT Notification Plugin
+    <MQTT+Notification+Plugin>`.
+
+    :arg str broker-url: the broker URL, as protocol://address:port (required)
+    :arg str credentials-id: credentials to use to connect to the broker
+    (optional)
+    :arg str topic: the message topic (default "jenkins/$PROJECT_URL")
+    :arg str message: the message itself (default "$BUILD_RESULT")
+    :arg str qos: one of AT_MOST_ONCE, AT_LEAST_ONCE, or EXACTLY_ONCE
+    (default AT_MOST_ONCE)
+    :arg bool retain-message: whether to resend message or not when a new
+    client connects (default false)
+
+    Minimal Example:
+
+    .. literalinclude:: /../../tests/publishers/fixtures/mqtt-minimal.yaml
+       :language: yaml
+
+    Full Example:
+
+    .. literalinclude:: /../../tests/publishers/fixtures/mqtt-full.yaml
+       :language: yaml
+    """
+
+    mqtt = XML.SubElement(xml_parent,
+                          'jenkins.plugins.mqttnotification.MqttNotifier')
+    mqtt.set('plugin', 'mqtt-notification-plugin')
+    mqtt_mapping = [
+        ('broker-url', 'brokerUrl', None), ]
+    helpers.convert_mapping_to_xml(mqtt, data, mqtt_mapping,
+                                   fail_required=True)
+    mqtt_mapping = [
+        ('credentials-id', 'credentialsId', None),
+        ('topic', 'topic', 'jenkins/$PROJECT_URL'),
+        ('message', 'message', '$BUILD_RESULT'),
+        ('qos', 'qos', 'AT_MOST_ONCE', {'AT_MOST_ONCE': '0',
+                                        'AT_LEAST_ONCE': '1',
+                                        'EXACTLY_ONCE': '2'}),
+        ('retain-message', 'retainMessage', False)
+    ]
+    helpers.convert_mapping_to_xml(mqtt, data, mqtt_mapping)
+
+
 def codecover(registry, xml_parent, data):
     """yaml: codecover
     This plugin allows you to capture code coverage report from CodeCover.

tests/publishers/fixtures/mqtt-full.xml

@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="utf-8"?>
+<project>
+  <publishers>
+    <jenkins.plugins.mqttnotification.MqttNotifier plugin="mqtt-notification-plugin">
+      <brokerUrl>tcp://localhost:1883</brokerUrl>
+      <credentialsId>abcde</credentialsId>
+      <topic>hello</topic>
+      <message>world</message>
+      <qos>2</qos>
+      <retainMessage>true</retainMessage>
+    </jenkins.plugins.mqttnotification.MqttNotifier>
+  </publishers>
+</project>

tests/publishers/fixtures/mqtt-full.yaml

@@ -0,0 +1,8 @@
+publishers:
+  - mqtt:
+      broker-url: tcp://localhost:1883
+      topic: hello
+      message: world
+      qos: EXACTLY_ONCE
+      retain-message: true
+      credentials-id: abcde

tests/publishers/fixtures/mqtt-minimal.xml

@@ -0,0 +1,12 @@
+<?xml version="1.0" encoding="utf-8"?>
+<project>
+  <publishers>
+    <jenkins.plugins.mqttnotification.MqttNotifier plugin="mqtt-notification-plugin">
+      <brokerUrl>tcp://localhost:1883</brokerUrl>
+      <topic>jenkins/$PROJECT_URL</topic>
+      <message>$BUILD_RESULT</message>
+      <qos>0</qos>
+      <retainMessage>false</retainMessage>
+    </jenkins.plugins.mqttnotification.MqttNotifier>
+  </publishers>
+</project>

tests/publishers/fixtures/mqtt-minimal.yaml

@@ -0,0 +1,3 @@
+publishers:
+  - mqtt:
+      broker-url: tcp://localhost:1883