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  1. ZABBIX BUGS AND ISSUES
  2. ZBX-15178

If "output template" references captured groups which do not exist in regexp then item value can be unpredictable

    Details

    • Team:
      Team A
    • Sprint:
      Sprint 46, Nov 2018, Sprint 47, Dec 2018
    • Story Points:
      3

      Description

      Steps to reproduce:
      1. Create item with 9 captured groups in regexp and all 10 possible groups in "output template":

       log[/home/zabbix/test.log,(ABC)(DEF)(GHI)(JKL)(MNO)(PQR)(STU)(VWX)(YZ),,,,g1:\1 g2:\2 g3:\3 g4:\4 g5:\5 g6:\6 g7:\7 g8:\8 g9:\9 g0:\0]
      

      2. Append to logfile a string: ABCDEFGHIJKLMNOPQRSTUVWXYZ
      Result is correct:

      g1:ABC g2:DEF g3:GHI g4:JKL g5:MNO g6:PQR g7:STU g8:VWX g9:YZ g0:ABCDEFGHIJKLMNOPQRSTUVWXYZ
      

      3. Reduce number of captured groups in regexp to 3, but leave all 10 groups in "output template" (do not restart agent):

      log[/home/zabbix/test.log,(ABC)(DEF)(GHI),,,,g1:\1 g2:\2 g3:\3 g4:\4 g5:\5 g6:\6 g7:\7 g8:\8 g9:\9 g0:\0]
      

      4. Append to logfile a string: ABCDEFGHIJKLMNOPQRSTUVWXYZ
      Result is incorrect:

      g1:ABC g2:DEF g3:GHI g4:JKL g5:MNO g6:PQR g7:STU g8:VWX g9:YZ g0:ABCDEFGHI
      

      Not-captured groups happen to contain their old values, although documentation https://www.zabbix.com/documentation/current/manual/config/items/itemtypes/zabbix_agent#supported_item_keys says that not-captured group is "an empty string if the N exceeds the number of captured groups".

      This bug is not limited to log[] and logrt[] items. Similar results can be demonstrated with item preprocessing if output template references capture groups which do not exist in the regexp.

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              • Assignee:
                Kalimulin Alex Kalimulin
                Reporter:
                andris Andris Mednis
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                • Created:
                  Updated:
                  Resolved: