Add SubscriptionOptions wrapper

[clintlombard]

Expose rmw_subscription_options as SubscriptionOptions.

Example usage:

import rclpy
from rclpy.node import Node
from rclpy.subscription_options import SubscriptionOptions
from std_msgs.msg import Float64


rclpy.init(args=None)
node = Node("test_sub_opts")

qos = 0

pubber_a = node.create_publisher(Float64, "test_float_a", qos)
pubber_b = node.create_publisher(Float64, "test_float_b", qos)

sub_opts = SubscriptionOptions()
sub_opts.ignore_local_publications = True

def simple_handler(msg):
    print(f"Received: {msg}")

node.create_subscription(
    Float64,
    "test_float_a",
    simple_handler,
    qos,
    subscription_options=sub_opts,
)
node.create_subscription(
    Float64,
    "test_float_b",
    simple_handler,
    qos,
)

for i in range(10):
    a = Float64(data=1.0 * i)
    b = Float64(data=2.0 * i)
    pubber_a.publish(a)
    pubber_b.publish(b)
    rclpy.spin_once(node)

node.destroy_node()
rclpy.shutdown()

Output:

Received: std_msgs.msg.Float64(data=2.0)
Received: std_msgs.msg.Float64(data=6.0)
Received: std_msgs.msg.Float64(data=10.0)
Received: std_msgs.msg.Float64(data=14.0)
Received: std_msgs.msg.Float64(data=18.0)

[fujitatomoya]

@clintlombard thanks for the contribution.

So after all, this exposes sub_opts.ignore_local_publications for rclpy, right?
Is there any related issue to address this feature? I think it would be nice to to support SubscriptionOptions and PublisherOptions.

[clintlombard]

@fujitatomoya I didn't find any applicable issues this was just based on a need I had for a tangential project.

I could also look at adding PublishOptions. Should I make a separate PR for that?

[adityapande-1995]

Just some minor comments, looks good to me !

[clintlombard]

Just some minor comments, looks good to me !

Thanks for catching those. All sorted

[fujitatomoya]

I was expecting that abstraction class such as QoSProfile with initialization, setter and getter accessors? so that it would be useful as python client library, and conceal implementation details with C/C++ language.

[clintlombard]

I was trying to keep the implementation more in line with the rclcpp interface, but can look at the changes this might require.

[fujitatomoya]

Good eye 👍

[fujitatomoya]

I believe that we need to add more test cases here,

• actually use SubscriptionOptions as argument. (Not None case)
• what is the default value for SubscriptionOptions?
• verify SubscriptionOptions member variables set by user application?

[clintlombard]

Good idea. I'll add a test case for this.