elastic/logstash

Create 'exec' filter

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#2,528 opened on Feb 6, 2015

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 (1 comment) (1 reaction) (0 assignees)Ruby (3,496 forks)batch import
help wantednew plugin

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Description

Migrated from https://logstash.jira.com/browse/LOGSTASH-119:

Would be useful to pipe arbitrary fields through a command to modify them.

Here's an example that would anonymize hostnames or something.

filter {
  exec {
    command => "sed -re 's/\S+\.loggly\.com/anonymizedhost.example.com/'"
    fields => [ "@message", "hostname", "@source_host" ]
  }
}

The default would use only the message to parse

The protocol between logstash and the exec filter must be strict. Something like: for every line emitted, one line must be emitted as the 'new' line. If no changes are made, simply print it unmodified.

deleting the field can be done by printing a blank line

we exec the process once and use stdin for sending data, stdout for reading responses; if it dies, some retries should occur

Contributor guide

Research direction
Study existing Logstash filter plugins (e.g., mutate, grok) to understand the plugin structure and lifecycle. Implement a new filter that spawns a child process, sends event field values via stdin line by line, reads stdout line by line, and replaces the field with the output. Handle process failures with retries. Ensure the config syntax (command, fields) is parsed correctly.
Tech stack
ruby
Domain
backend
Issue type
Feature
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.
Half day
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
RubyCommand line
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
65