Custom messages not found?

[renatosamperio]

Hi,

Many thanks for your library as it has become very useful. However, recently I had found some issues that perhaps you could help me to clarify.

I am trying to make use of custom defined messages from another module but I receive the error:
TypeError: Cannot read property 'msg' of undefined

I am including the custom message module in the package.xml as build_depend and exec_depend and in the CMakelists.txt in the parts related to find_package and CATKIN_DEPENDS of the "catkin_package".

I also tried to load the messages explicitly with rosnodejs.loadAllPackages(); before calling the require of the custom-made module, but this only works when I execute the node inside the ROS module.

I installed the node_modules/ inside the ROS module itself. The file structure looks like this:

my_ws/

custom_messages_module/

msg/

myMessage.msg

error_module/

scripts/

node_modules/
package-lock.json
ros_node_script.js

user@host: ~/my_ws$ rosrun error_module ros_node_script.js
TypeError: Cannot read property 'msg' of undefined

The file ros_node_script.js would look like this:
#!/usr/bin/env node
const rosnodejs = require('rosnodejs');
rosnodejs.loadAllPackages();
const custom_messages_module = rosnodejs.require('custom_messages_module').msg;

Any idea would be very helpful.

Regards,
Renato.

[chris-smith]

rosnodejs.loadAllPackages is asynchronous and so it won't have managed to build anything by the time you try to require them. Waiting for the promise to resolve would likely not resolve the issue either though as we only search for messages on disk once when rosnodejs is first loaded.

loadAllPackages is meant as a one-time build step, so I'd recommend running it on its own and verifying that it mentions your custom_messages_module somewhere in the output

$ node
> const rosnodejs = require('rosnodejs');
> rosnodejs.loadAllPackages();
Promise { <pending> }
> Finished building package topic_tools
Finished building package std_msgs
Finished building package nodelet
Finished building package std_srvs
Finished building package custom_messages_module
Finished building messages!

After this, run your ros_node_script.js file without the loadAllPackages() line. You could also generate messages on the fly rather than relying on them from disk, but you wouldn't be able to require any message packages until the node has initialized

rosnodejs.initNode('my_node', { onTheFly: true })
.then(() => {
  const custom_messages_module = rosnodejs.require('custom_messages_module').msg;
});

[renatosamperio]

Dear Chris,

Many thanks for your reply.

I had changed the onTheFly part in the initNode as you suggested and it worked. However, I had noticed that without the onTheFly section, if I generate a message module with 1 message it keeps finding the module and using correctly the message. However, whenever I use a module with 57 messages it generates an error:

TypeError: Cannot read property 'msg' of undefined at Object.<anonymous> (/home/sfl/workspace/sample_js_ws/src/js_module/scripts/ros_node_script.js:27:65) at Module._compile (module.js:635:30) at Object.Module._extensions..js (module.js:646:10) at Module.load (module.js:554:32) at tryModuleLoad (module.js:497:12) at Function.Module._load (module.js:489:3) at Function.Module.runMain (module.js:676:10) at startup (bootstrap_node.js:187:16) at bootstrap_node.js:608:3

I had dissected as much as I could the issue in the following repository as we have message calls out of the initNode :

• sample_js_ws

I had made two modules that generate messages. One module follows existing online examples with 1 message (custom_messages_module) and the other one has 57 messages and depends on geometry_msgs (more_custom_msgs).

I had also created a bash file (build_script.bash) that is based in the rosnodejs online examples and shows how I am actually compiling the ROS workspace. At the end, it also executes the sample node.

The sample node calls successfully the message module with 1 message but it fails to call the 57 messages module (out of the initNode). I had looked around the issue and try different things (e. g. increase node heap, play around with loadAllPackages) but I still don't know why the number of messages could be an issue.

Any feedback would be very welcome.

Regards,

Renato.

[chris-smith]

From the root of your workspace, what is the output of

$ ls devel/share/gennodejs/ros

Also, what is the output of loadAllPackages()? And what version of node?

[renatosamperio]

Dear Chris,

I placed the outputs you requested in the following PASTEBIN.

Let me know if it would not be visible.

Regards,

Renato.

[chris-smith]

I can't reproduce your issue if I run loadAllPackages(). Without running loadAllPackages() I'm running into the issue in #85 where an error is being swallowed during the require call - your CMakeLists.txt isn't building Sfl_Sound_Vibe. Try requiring the message package on it's own instead of through rosnodejs

$ node
> require('./devel/share/gennodejs/ros/more_custom_msgs/_index.js')

[renatosamperio]

Hi Chris,

Thanks a lot for your message. I was able to replicate and solve my issue.

I had removed from CMakelists.txt some (4) msg files that were never deleted, I could track them in:
.../devel/share/gennodejs/ros/hive_msgs/msg/

but not in .../devel/.private/hive_msgs/share/gennodejs/ros/hive_msgs/msg/.

I needed to debug message_utils.js and message_cache.js to track the issue. Somethow catkin still makes use of any message contained in /msg and then rosnodejs tries to make use of such files. What is not funny is that rosnodejs crashes silently without saying anything (e. g. files are missing) but a failure in requiring a message.

Regards,

Renato.

[chris-smith]

Agreed. I believe this should be resolved by #94 - feel free to reopen if something is still missing.