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Missing compile step?

asked 2017-07-26 11:03:54 -0500

pitosalas gravatar image

updated 2017-07-27 13:57:47 -0500

I'm learning ROS for Turtlebot3, and am getting an error message that appears to tell me that I missed a compilation or build step. Perhaps I am missing an environment variable. Here are the key steps:

$ catkin_create_pkg wanderbot rospy geometry_msgs sensor_msgs

$ source ~/catkin_ws/devel/setup.bash 
pitosalas@ubuntu:~/catkin_ws/wanderbot/src$ ./redgreen.py 
from: can't read /var/mail/geometry_msgs.msg
./redgreen.py: line 6: syntax error near unexpected token `('
./redgreen.py: line 6: `cmd_vel_pub = rospy.Publisher('cmd_vel', Twist, queue_size=1) #<1>'

And looking for the missing geometry_msgs.msg:

pitosalas@ubuntu:/$ ls -l /opt/ros/kinetic/share/geometry_msgs/
total 12
drwxr-xr-x 2 root root 4096 Jul 23 18:39 cmake
drwxr-xr-x 2 root root 4096 Jul 23 18:39 msg
-rw-r--r-- 1 root root  794 Sep 30  2016 package.xml

And inside you can see the Twist.msg:

ls -l /opt/ros/kinetic/share/geometry_msgs/msg/
total 116
-rw-r--r-- 1 root root 119 Sep 30  2016 Accel.msg
-rw-r--r-- 1 root root  83 Sep 30  2016 AccelStamped.msg
-rw-r--r-- 1 root root 330 Sep 30  2016 AccelWithCovariance.msg
-rw-r--r-- 1 root root 124 Sep 30  2016 AccelWithCovarianceStamped.msg
-rw-r--r-- 1 root root 235 Sep 30  2016 Inertia.msg
-rw-r--r-- 1 root root  30 Sep 30  2016 InertiaStamped.msg
-rw-r--r-- 1 root root 367 Sep 30  2016 Point32.msg
-rw-r--r-- 1 root root  84 Sep 30  2016 Point.msg
-rw-r--r-- 1 root root  98 Sep 30  2016 PointStamped.msg
-rw-r--r-- 1 root root 107 Sep 30  2016 Polygon.msg
-rw-r--r-- 1 root root 104 Sep 30  2016 PolygonStamped.msg
-rw-r--r-- 1 root root  96 Sep 30  2016 Pose2D.msg
-rw-r--r-- 1 root root  85 Sep 30  2016 PoseArray.msg
-rw-r--r-- 1 root root 119 Sep 30  2016 Pose.msg
-rw-r--r-- 1 root root  79 Sep 30  2016 PoseStamped.msg
-rw-r--r-- 1 root root 323 Sep 30  2016 PoseWithCovariance.msg
-rw-r--r-- 1 root root 122 Sep 30  2016 PoseWithCovarianceStamped.msg
-rw-r--r-- 1 root root 108 Sep 30  2016 Quaternion.msg
-rw-r--r-- 1 root root 117 Sep 30  2016 QuaternionStamped.msg
-rw-r--r-- 1 root root 118 Sep 30  2016 Transform.msg
-rw-r--r-- 1 root root 337 Sep 30  2016 TransformStamped.msg
-rw-r--r-- 1 root root 115 Sep 30  2016 Twist.msg
-rw-r--r-- 1 root root  82 Sep 30  2016 TwistStamped.msg
-rw-r--r-- 1 root root 326 Sep 30  2016 TwistWithCovariance.msg
-rw-r--r-- 1 root root 124 Sep 30  2016 TwistWithCovarianceStamped.msg
-rw-r--r-- 1 root root 382 Sep 30  2016 Vector3.msg
-rw-r--r-- 1 root root 103 Sep 30  2016 Vector3Stamped.msg
-rw-r--r-- 1 root root 117 Sep 30  2016 Wrench.msg
-rw-r--r-- 1 root root  85 Sep 30  2016 WrenchStamped.msg
pitosalas@ubuntu:/$

Here's the full source of red green.py:

#example 1
#!/usr/bin/env python
import rospy
from geometry_msgs.msg import Twist

cmd_vel_pub = rospy.Publisher('cmd_vel', Twist, queue_size=1) #<1>
rospy.init_node('red_light_green_light')

red_light_twist = Twist() #<2>
green_light_twist = Twist()
green_light_twist.linear.x = 0.5 #<3>

driving_forward = False
light_change_time = rospy.Time.now()
rate = rospy.Rate(10)

while not rospy.is_shutdown():
  if ...
(more)
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Comments

Why is the wanderbot package outside your src space? That won't work (well it can, but let's not complicate things).

Put it in catkin_ws/src, run catkin_make (or catkin build), source your devel/setup.bash and try again.

Also, check what you have on line 6 of redgreen.py.

gvdhoorn gravatar image gvdhoorn  ( 2017-07-26 15:48:18 -0500 )edit

Thanks @gvdhoorn... I made the suggested corrections, and updated the original question above. Then run it with cd ~./catkin_ws/src/wanderbot/src; ./redgreen.py and got the same error. Any other suggestion would be appreciated!

pitosalas gravatar image pitosalas  ( 2017-07-26 19:05:44 -0500 )edit

It looks like you're not finding geometry_msgs in /var/mail (from: can't read /var/mail/geometry_msgs.msg). Where is it installed on your system? I'm on Ubuntu 14.04 and using Indigo, and it's installed at /opt/ros/indigo/share/geometry_msgs.

jayess gravatar image jayess  ( 2017-07-26 19:37:01 -0500 )edit

@jayess, thanks, it seems to be there. Also I've updated the original question with that detail and some more. Thanks for sticking with me!

pitosalas gravatar image pitosalas  ( 2017-07-26 21:02:23 -0500 )edit

Make sure to post the entire contents of your source. I ran the previous edit of your code and didn't get any errors. I ran the current version and got your errorl

jayess gravatar image jayess  ( 2017-07-27 15:18:25 -0500 )edit

yes. I guess I was trying to unclutter the question before I had any idea that that comment was the culprit!

pitosalas gravatar image pitosalas  ( 2017-07-27 15:26:25 -0500 )edit

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answered 2017-07-27 13:57:09 -0500

pitosalas gravatar image

I think I found the problem: the first line of the .py file was a #comment... before the shebang line. I think thats what messed everything up!

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Comments

If this solved your question you should mark it as correct.

jayess gravatar image jayess  ( 2017-07-27 15:18:51 -0500 )edit

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Asked: 2017-07-26 11:03:54 -0500

Seen: 276 times

Last updated: Jul 27 '17