Flaky Test

Unix input tests are flaky at least in OSX in Travis.

• Test Name: filebeat/tests/system/test_unix.py
• Branch: master
• Notes:
  • Error is about Too many open files.
  • I couldn't reproduce it locally on Linux.
  • I could reproduce a similar trace reducing with ulimit the limit of open files to 16 (but I don't think the problem is that open files limit is too low in Travis OSX workers).
  • When running the tests locally, I see that there is at least one error trying to use a closed connection, I think that from here. Once I saw many errors there, like if there was some race condition between the channel is done and the connection is closed. Long shot, but I wonder if this loop can somehow create many file descriptors under some circumstances.

Stack Trace

Can be found for example here: https://travis-ci.org/github/elastic/beats/jobs/723425803#L2473