Update spawner to have a timeout on service call

[gennartan]

In some cases, the service call might never return. As a consequence, the call to spin_until_future_complete will loop infinitely.

When the error happens:

• The spawner is blocked
• The controller manager shows the following error: [controller_manager.rclcpp]: failed to send response to /controller_manager/list_controllers (timeout): client will not receive response, at ./src/rmw_response.cpp:154, at ./src/rcl/service.c:402

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[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 86.64%. Comparing base (af4b48f) to head (e25efe8).

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1566      +/-   ##
==========================================
- Coverage   86.67%   86.64%   -0.03%     
==========================================
  Files         115      115              
  Lines       10528    10529       +1     
  Branches      967      967              
==========================================
- Hits         9125     9123       -2     
- Misses       1056     1058       +2     
- Partials      347      348       +1     

Flag	Coverage Δ
unittests	86.64% <100.00%> (-0.03%)	:arrow_down:

Flags with carried forward coverage won't be shown. Click here to find out more.

Files	Coverage Δ
.../controller_manager/controller_manager_services.py	67.74% <100.00%> (ø)

... and 1 file with indirect coverage changes

[fmauch]

Related: #1501

[gennartan]

Related: #1501

Yes, PR #1501 seems to add the usage of timeout_sec of spin_until_future_complete as I did here. With two main differences:

• PR #1501 uses the same service_timeout variable to wait that the service is ready and to call the actual service.
• PR #1501 automatically retries to call the failed service

I don't know what would be the expected behavior from the maintainers. It is up to them to decide which behavior is prefered.

That said, I think merging one of those PR could be a priority since it is a bug in ros2_control that can prevent a robot to start. In my case, I am starting the spawner in a launchfile and in about 30% of the cases, I must manually restart the spawner because the node didn't start correctly. Other projects in my company had the same issues.

[destogl]

Closing in favor of #1501 (decided on WG Meeting Aug. 14th)