Problem description
I think there is a bug in how docker prints information to terminal, at least with respect to ROS_INFO. For a simple ROS HelloWorld program that uses just ROS_INFO, the message isn’t printed; but if I add a cout message, then both print. The fact that ROS_INFO prints if cout is present leads me to believe this isn’t a ROS bug.
Relevant info:
Dockerfile
FROM ros:kinetic
docker-compose.yml
version: '2'
services:
master:
build: .
container_name: master
command: roscore
t1:
build: .
container_name: t1
environment:
- "ROS_HOSTNAME=t1"
- "ROS_MASTER_URI=http://master:11311"
volumes:
- ~/catkin_ws:/repo
command: /repo/docker-command.sh
docker-command.sh
#!/bin/bash
# wait for roscore
sleep 2 # at least 2
cp -r /repo/devel/lib/trial /opt/ros/kinetic/lib
source /ros_entrypoint.sh
rosrun trial HelloWorld
# don't stop container
while true; do sleep 1000; done
HelloWorld.cpp
#include <ros/ros.h>
using namespace std;
int main(int argc, char** argv) {
ros::init(argc, argv, "trial");
ROS_INFO("Hello World!");
cout << "Hello World 2!" << endl;
ros::spin();
return 0;
}
Output with only ROS_INFO print (commenting the line cout << "Hello World 2!" << endl;)
nathan@nathan-ma-vm1:~/catkin_ws$ docker-compose up
Starting master
Starting t1
Attaching to t1, master
t1 | [rospack] Error: package 'trial' not found
t1 | find: ‘’: No such file or directory
^CGracefully stopping... (press Ctrl+C again to force)
Output with both prints
nathan@nathan-ma-vm1:~/catkin_ws$ docker-compose up
Starting master
Starting t1
Attaching to master, t1
t1 | [rospack] Error: package 'trial' not found
t1 | find: ‘’: No such file or directory
t1 | [ INFO] [1524672395.044437305]: Hello World!
t1 | Hello World 2!
^CGracefully stopping... (press Ctrl+C again to force)