Blank lines / "(no name)" in output of ros2 node list

[dhood]

Not a major issue but something we should look into eventually:

built from source with fastrtps on linux:

<ros2 run demo_nodes_cpp add_two_ints_server>
dhood@osrf-esteve:~/ros2_ardent [ros2_ardent]$ ros2 node list
add_two_ints_server
<kill server node>
dhood@osrf-esteve:~/ros2_ardent [ros2_ardent]$ ros2 node list




<start it again>
dhood@osrf-esteve:~/ros2_ardent [ros2_ardent]$ ros2 node list




add_two_ints_server
<kill it again>
dhood@osrf-esteve:~/ros2_ardent [ros2_ardent]$ ros2 node list



dhood@osrf-esteve:~/ros2_ardent [ros2_ardent]$ 

built from source with connext on osx:

$ RMW_IMPLEMENTATION=rmw_connext_cpp ros2 node list
REDAWorker_enterExclusiveArea:worker U00007fff7a779300 deadlock risk: cannot enter 0x7fa690f9c770 of level 40 from level 40
REDACursor_modifyReadWriteArea:!enter worker (U00007fff7a779300)'s exclusive area
PRESPsService_removeRemoteEndpoint:!modify pres psRemoteWriter
REDAWorker_enterExclusiveArea:worker U00007fff7a779300 deadlock risk: cannot enter 0x7fa690f9c770 of level 40 from level 40
REDACursor_modifyReadWriteArea:!enter worker (U00007fff7a779300)'s exclusive area
PRESPsService_removeRemoteEndpoint:!modify pres psRemoteReader
add_two_ints_server
(no name)
(no name)
(no name)
(no name)

the (no name) output comes from this line in rmw_connext_cpp:
https://github.com/ros2/rmw_connext/blob/efaf513a5f9303216670ed76b5060ed5b8f958e5/rmw_connext_shared_cpp/src/node_names.cpp#L76

Perhaps this equivalent in fastrtps can return empty names: https://github.com/ros2/rmw_fastrtps/blob/3e5edb3316e2aee325e9354549e54c999a89bca9/rmw_fastrtps_cpp/src/rmw_node_names.cpp#L56

I haven't seen opensplice output empty lines.

[Karsten1987]

I have the same output for fastrtps on osx.

Reproducible for me when starting a talker with opensplice, and calling rosnode list on fastrtps

[mikaelarguedas]

oh weird. Just to confirm: that's something you both see only on MacOS (and not on Linux)?

[dhood]

I edited my first post to clarify the first output is from fastrtps on linux. @tfoote saw it on windows in #69 so this is cross-platform FWICT

[dirk-thomas]

I ran the same sequence on Linux (build from source) and the node list is always correct for me (no sign of empty lines).

[tfoote]

I have three ways to reproduce it.

One

• FastRTPS window: ros2 daemon start
• OpenSplice window: ros2 node list OK with config file error

C:\Users\OSRF\Downloads\ardent_opensplice\ros2-windows>ros2 node list
========================================================================================
Report      : ERROR
Date        : Thu Dec 07 12:23:08 Pacific Standard Time 2017
Description : Failed to open configuration syntax file: C:/dev/opensplice/HDE/x86_64.win64\etc\metaconfig.xml
Node        : DESKTOP-1VF050Q
Process     : python.exe <5716>
Thread      : spliced 5688
Internals   : 6.7.171127OSS/fcc005a2/fcc005a2/configuration validator/cfg_validator.c/825/0/1512678188.615544300/0

C:\Users\OSRF\Downloads\ardent_opensplice\ros2-windows>

• FastRTPS window: ros2 node list

C:\Users\OSRF\Downloads\ardent_fastrtps\ros2-windows>ros2 node list





C:\Users\OSRF\Downloads\ardent_fastrtps\ros2-windows>

two

• OpenSplice window ros2 daemon start
• FastRTPS window: ros2 node list

C:\Users\OSRF\Downloads\ardent_fastrtps\ros2-windows>ros2 node list





C:\Users\OSRF\Downloads\ardent_fastrtps\ros2-windows>

three

• FastRTPS window: ros2 daemon start
• OpenSplice window: ros2 run lifecycle lifecycle_listener
• FastRTPS window: ros2 node list

C:\Users\OSRF\Downloads\ardent_fastrtps\ros2-windows>ros2 node list
lc_listener





C:\Users\OSRF\Downloads\ardent_fastrtps\ros2-windows>

[dhood]

I think having opensplice nodes running is what causes the extra output.

Having only fastrtps/connext nodes I see expected output from RMW_IMPLEMENTATION=rmw_fastrtps_cpp ros2 node list (no padding) and RMW_IMPLEMENTATION=rmw_connext_cpp ros2 node list (no "(no name)").

When opensplice nodes are introduced the output happens.

I've noticed that RMW_IMPLEMENTATION=rmw_opensplice_cpp ros2 node list:

• is able to detect opensplice nodes without error
• does not report opensplice nodes as having shut down immediately
• cannot detect connext/fastrtps nodes

I suspect there may be general discovery incompatibility that causes rmw_get_node_names to have errors when fastrtps/connext are requesting status of opensplice participants, and it looks like opensplice can't detect the others either

[dirk-thomas]

I don't think that this is related to the daemon at all.

You can try the following to reproduce:

• make sure no other processes are running
• start any node using OpenSplice (without ros2 run but invoking the executable directly)
• call ros2 node list using FastRTPS (which will start a daemon using FastRTPS)

which leads to the same result: the node list containing empty lines.

[dirk-thomas]

The reason for the problem as well as a possible solution to fix this is described in ros2/ros2#438.

[dirk-thomas]

Addressed by #76.