Exposing publisher queue_size and latch (#88)

* Working to improve the ROS TCP connector by adding queues and latching.

* Exposing the latch parameter for ROS publishers.

* Updating the CHANGELOG

* Improving style for publish method definition.

Author: P3TE

CHANGELOG.md

@@ -14,6 +14,8 @@ Add the [Close Stale Issues](https://github.com/marketplace/actions/close-stale-
 
 ### Added
 
+Support for queue_size and latch for publishers. (https://github.com/Unity-Technologies/ROS-TCP-Endpoint/issues/82)
+
 ### Changed
 
 ### Deprecated

src/ros_tcp_endpoint/publisher.py

@@ -22,8 +22,7 @@ class RosPublisher(RosSender):
     Class to publish messages to a ROS topic
     """
 
-    # TODO: surface latch functionality
-    def __init__(self, topic, message_class, queue_size=10):
+    def __init__(self, topic, message_class, queue_size=10, latch=False):
         """
 
         Args:
@@ -33,7 +32,7 @@ def __init__(self, topic, message_class, queue_size=10):
         """
         RosSender.__init__(self)
         self.msg = message_class()
-        self.pub = rospy.Publisher(topic, message_class, queue_size=queue_size)
+        self.pub = rospy.Publisher(topic, message_class, queue_size=queue_size, latch=latch)
 
     def send(self, data):
         """

src/ros_tcp_endpoint/server.py

@@ -141,7 +141,7 @@ def subscribe(self, topic, message_name):
             topic, message_class, self.tcp_server
         )
 
-    def publish(self, topic, message_name):
+    def publish(self, topic, message_name, queue_size=10, latch=False):
         if topic == "":
             self.tcp_server.send_unity_error(
                 "Can't publish to a blank topic name! SysCommand.publish({}, {})".format(
@@ -163,7 +163,7 @@ def publish(self, topic, message_name):
             self.tcp_server.source_destination_dict[topic].unregister()
 
         self.tcp_server.source_destination_dict[topic] = RosPublisher(
-            topic, message_class, queue_size=10
+            topic, message_class, queue_size, latch
         )
 
     def ros_service(self, topic, message_name):