Bug with multimaster_fkie

[Filea]

Good morning.

Everytime that I try to subscribe a ROS topic using ROSGO and with a multimaster_fkie connection between two robots, the subscriber crashes and the following error is displayed:

Received: asd
2020/05/11 11:42:16 [DEBUG] 7
2020/05/11 11:42:16 [DEBUG] Receive msgChan
2020/05/11 11:42:16 [DEBUG] Callback job enqueued.
2020/05/11 11:42:16 [DEBUG] Loop
2020/05/11 11:42:16 [DEBUG] Execute job
Received: asd
2020/05/11 11:42:16 [DEBUG] Slave API publisherUpdate() called.
2020/05/11 11:42:16 [DEBUG] Receive pubListChan
2020/05/11 11:42:16 [DEBUG] Slave API publisherUpdate() called.
2020/05/11 11:42:16 [FATAL] [DefaultSubscriber] ROS Master API call failed with code -1: Not a publisher of [/chatter]

Best,
Filipe

[cjds]

I've not actually tried multimaster yet. I will try it and get back to you. In the meantime can you give me a minimal go example that I could run?

[Filea]

Good afternoon,

Thank you for your response.
Sure, you just need to have two machines within the same network, multimaster_fkie installed on both machines and ROSGO.

Machine 1:

• roslaunch master_discovery_fkie master_discovery.launch
• roslaunch master_sync_fkie master_sync.launch
• rostopic pub /test std_msgs/String "data: 'Hey'" -r 20

Machine 2:

• roslaunch master_discovery_fkie master_discovery.launch
• roslaunch master_sync_fkie master_sync.launch
• rostopic echo /test ( just to make sure that you can see what the other machine is sending)
• go build string_sub.go
• ./string_sub

The program will die after a while with the following error:

Received: Hey
2020/05/19 17:21:29 [DEBUG] Slave API publisherUpdate() called.
2020/05/19 17:21:29 [DEBUG] Receive pubListChan
2020/05/19 17:21:29 [DEBUG] Slave API publisherUpdate() called.
2020/05/19 17:21:29 [FATAL] [DefaultSubscriber] ROS Master API call failed with code -1: Not a publisher of [/test]

ROSGO subscriber that I'm using:

package main

//go:generate gengo msg std_msgs/String
import (
	"fmt"
	"os"
	"std_msgs"

	"github.com/fetchrobotics/rosgo/ros"
)

func callback(msg *std_msgs.String) {
	fmt.Printf("Received: %s\n", msg.Data)
}

func main() {
	node, err := ros.NewNode("/listener", os.Args)
	if err != nil {
		fmt.Println(err)
		os.Exit(-1)
	}
	defer node.Shutdown()
	node.Logger().SetSeverity(ros.LogLevelDebug)
	node.NewSubscriber("/test", std_msgs.MsgString, callback)
	node.Spin()
}

[cjds]

Interesting. I'll take a look

[Filea]

Thank you.
Let me know if you need anything else.

[cjds]

I'm trying to look into this but I'm having trouble replicating.

1. What version of ROS are you using?
2. master_discovery.launch can you hand me the code in this file? I can't find the reference to it in this repo https://github.com/fkie/multimaster_fkie
3. Does this work with pure rostopic echo rostopic pub on both machines? Does this work with Python on both ends?