Do not fail es-cleaner if there are no jaeger indices

[pavolloffay]

Resolves #1468

The original stacktrace

Traceback (most recent call last):
  File "plugin/storage/es/esCleaner.py", line 89, in <module>
    main()
  File "plugin/storage/es/esCleaner.py", line 49, in main
    filter_main_indices(ilo, prefix)
  File "plugin/storage/es/esCleaner.py", line 65, in filter_main_indices
    ilo.filter_by_age(source='name', direction='older', timestring='%Y-%m-%d', unit='days', unit_count=int(sys.argv[1]))
  File "/usr/local/lib/python3.6/site-packages/curator/indexlist.py", line 495, in filter_by_age
    stats_result=stats_result
  File "/usr/local/lib/python3.6/site-packages/curator/indexlist.py", line 356, in _calculate_ages
    self._get_name_based_ages(timestring)
  File "/usr/local/lib/python3.6/site-packages/curator/indexlist.py", line 279, in _get_name_based_ages
    self.empty_list_check()
  File "/usr/local/lib/python3.6/site-packages/curator/indexlist.py", line 226, in empty_list_check
    raise exceptions.NoIndices('index_list object is empty.')
curator.exceptions.NoIndices: index_list object is empty.

I have tested this with ES 5.x and 6.x. Archive storage works also fine.

[codecov]

Codecov Report

Merging #1569 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #1569   +/-   ##
=======================================
  Coverage   98.79%   98.79%           
=======================================
  Files         190      190           
  Lines        9063     9063           
=======================================
  Hits         8954     8954           
  Misses         85       85           
  Partials       24       24

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[yurishkuro]

empty_list function seems to kill the process if the list is empty (better name would be panic_if_list_empty)

so how does this achieve "do not fail" objective?

[pavolloffay]

empty_list ends the process with 0 which indicates success. This is exactly what we want. Without this fix the process is not ended and an exception is thrown.

[objectiser]

@pavolloffay Just checking - you say archive storage works fine, but shouldn't filter_archive_indices also have the same empty_list check?

[pavolloffay]

Yes the archive storage wors well. The methods invoked in ilo does not fail if the list is empty.