Add config option to set QOS of published messages

This commit adds a new config option to germqtt to set the QOS level
for messages published. By default it'll use 0, but if operating in
an environment where more guarantees are needed on delivery you can
set this to be higher now.

Change-Id: I7bf07921ce2f94a9a34f468294a1a5f1da2673af

README.rst

@@ -70,6 +70,9 @@ can set:
                   with.
  * **password** - Used to set the auth password to connect to the MQTT broker
                   with. A username must be set for this option to be used.
+ * **qos** - Used to set the QOS level for the messages published by germqtt.
+             For more information on the different QOS levels refer to:
+             https://mosquitto.org/man/mqtt-7.html
 
 Other Settings
 --------------

etc/germqtt.conf

@@ -9,3 +9,4 @@ key=/home/computertreker/.ssh/id_rsa
 [mqtt]
 hostname=localhost
 topic=gerrit
+qos = 2

germqtt/germqtt.py

@@ -50,7 +50,7 @@ class GerritStream(object):
 
 class PushMQTT(object):
     def __init__(self, hostname, port=1883, client_id=None,
-                 keepalive=60, will=None, auth=None, tls=None):
+                 keepalive=60, will=None, auth=None, tls=None, qos=0):
         self.hostname = hostname
         self.port = port
         self.client_id = client_id
@@ -58,18 +58,19 @@ class PushMQTT(object):
         self.will = will
         self.auth = auth
         self.tls = tls
+        self.qos = qos
 
     def publish_single(self, topic, msg):
         publish.single(topic, msg, hostname=self.hostname,
                        port=self.port, client_id=self.client_id,
                        keepalive=self.keepalive, will=self.will,
-                       auth=self.auth, tls=self.tls)
+                       auth=self.auth, tls=self.tls, qos=self.qos)
 
     def publish_multiple(self, topic, msg):
         publish.multiple(topic, msg, hostname=self.hostname,
                          port=self.port, client_id=self.client_id,
                          keepalive=self.keepalive, will=self.will,
-                         auth=self.auth, tls=self.tls)
+                         auth=self.auth, tls=self.tls, qos=self.qos)
 
 
 def get_options():
@@ -131,11 +132,18 @@ def _main(args, config):
         if mqtt_password:
             auth['password'] = mqtt_password
 
+    # QOS setting
+    if config.has_option('mqtt', 'qos'):
+        mqtt_qos = config.getint('mqtt', 'qos')
+    else:
+        mqtt_qos = 0
+
     mqttqueue = PushMQTT(
         config.get('mqtt', 'hostname'),
         port=mqtt_port,
         keepalive=keepalive,
-        auth=auth)
+        auth=auth,
+        qos=mqtt_qos)
 
     base_topic = config.get('mqtt', 'topic')
     while True: