Installing ros-noetic-rosbridge-server misses bson dependency

[ruben-arts]

After installing rosbridge-server with Conda, you will get issues with the bson dependency.

When trying to run the rosbridge-server you will be missing the bson module.

Error log:

 Log opened.
 Traceback (most recent call last):
   File "/home/mamba/bson-test/.env/lib/rosbridge_server/rosbridge_websocket", line 48, in <module>
     from rosbridge_server import ClientManager
   File "/home/mamba/bson-test/.env/lib/python3.8/site-packages/rosbridge_server/__init__.py", line 2, in <module>
     from .websocket_handler import RosbridgeWebSocket
  File "/home/mamba/bson-test/.env/lib/python3.8/site-packages/rosbridge_server/websocket_handler.py", line 49, in <module>
     from rosbridge_library.rosbridge_protocol import RosbridgeProtocol
   File "/home/mamba/bson-test/.env/lib/python3.8/site-packages/rosbridge_library/rosbridge_protocol.py", line 34, in <module>
     from rosbridge_library.protocol import Protocol
   File "/home/mamba/bson-test/.env/lib/python3.8/site-packages/rosbridge_library/protocol.py", line 43, in <module>
     from rosbridge_library.util import json, bson
   File "/home/mamba/bson-test/.env/lib/python3.8/site-packages/rosbridge_library/util/__init__.py", line 19, in <module>
     import bson
ModuleNotFoundError: No module named 'bson'

This issue is known and the fix would be installing the pymongo library.

So the workaround for now is installing pymongo :

pip install pymongo
# OR 
conda install -c conda-forge pymongo

Could this be added as a dependency?

[wolfv]

Hi, thanks for discovering this! Yes, indeed, that seems like the proper fix!

We can add dependencies in patch/dependencies.yaml file. Do you want to send a PR?

[ruben-arts]

Oh after making that PR I see I miss read your suggestion. Would it be enough to add a instance of rosbridge-library to the dependencies.yaml ?

[wolfv]

yes, just adding that to dependencies.yaml should be enough. I think your way also unfortunately doesn't work because we generate the recipes before we're patching them :)