Try USER variable to retrieve the username.

[iwanders]

🦟 Bug fix

Summary

This resolves a situation where gazebo is endlessly spamming:

Error getting username: no matching password record.

In our case, this triggered because a system was configured with ldap, but at runtime the libnss_systemd library wasn't available. This meant the user name lookup through ldap failed, and the fallback by reading it from /etc/passwd didn't work as the user wasn't present there. It can probably be reproduced by making the getpwuid_r always fail.

Basically, all this complexity can be removed by just checking the $USER environment variable. That is unlikely to fail on any linux system. I left the old behaviour in place as a fallback for if USER is not set, but I can't think of a situation where that would be.

Checklist

• Signed all commits for DCO
• Added tests -> there's one that checks if the user name is empty here
• Updated documentation (as needed)
• Updated migration guide (as needed)
• codecheck passed (See contributing)
• All tests passed (See test coverage)
• While waiting for a review on your PR, please help review another open pull request to support the maintainers

Note to maintainers: Remember to use Squash-Merge and edit the commit message to match the pull request summary while retaining Signed-off-by messages.

[codecov]

Codecov Report

Merging #282 (be37fcc) into ign-transport11 (f3c8f8b) will decrease coverage by 0.01%.
The diff coverage is 66.66%.

@@                 Coverage Diff                 @@
##           ign-transport11     #282      +/-   ##
===================================================
- Coverage            89.07%   89.06%   -0.02%     
===================================================
  Files                   51       51              
  Lines                 4769     4772       +3     
===================================================
+ Hits                  4248     4250       +2     
- Misses                 521      522       +1     

Impacted Files	Coverage Δ
src/NetUtils.cc	72.56% <66.66%> (-0.17%)	⬇️

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[caguero]

It looks good to me, thanks for the patch!

[caguero]

Well, one little request. Could you rename user_variable to userVariable to be consistent with our style?

[iwanders]

@caguero, certainly, I've pushed a new commit where we use userVariable instead of user_variable. So used to the ros styleguide that I didn't even think of checking whether the variable name I used matched the style guide. Sorry about that.