elastic/logstash

Grok custom pattern problem (Can't start with a number) - Logstash 1.5

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#3,353 opened on Jun 1, 2015

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Description

Hi,

it was previously OK with Logstash 1.4.2 it now BUG with Logstash 1.5

My pattern file contain a grok pattern with a name starting with a number

Step to reproduce :

1 - Add this pattern to grok patterns :

  • 123_DATE %{YEAR:123_date}
  • YEAR_DATE %{YEAR:year_date}

2 - Start Logstash with the following commands :

  • ./logstash agent -e 'filter { grok { match => ["message","%{123_DATE:year}"] } }'
  • ./logstash agent -e 'filter { grok { match => ["message","%{YEAR_DATE:year}"] } }'

3 - RESULTS

  • Logstash 1.4.2
    • Logstash 1.5

Please correct this or just write it somewhere in red inside the documentation.

EDIT : Please note that a name like this : DATE_123_CUSTOM is ok because the name is not starting with a number. (I've just made the test)

M0dM

Contributor guide

Research direction
Investigate the Logstash grok filter code, likely in the Logstash Ruby source (e.g., lib/logstash/filters/grok.rb). The error 'invalid group name' suggests the regex generation rejects pattern names starting with a digit. A fix could involve allowing such names or adding a note in documentation. Check the changelog between 1.4.2 and 1.5 to identify the change that introduced this limitation.
Tech stack
ruby
Domain
backend
Issue type
Bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
familiarity with Logstash grok filterunderstanding of Ruby regex named groups
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
70