Grep

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The Grep Filter plugin allows to match or exclude specific records based in regular expression patterns.

Configuration Parameters

The plugin supports the following configuration parameters:

Key

Value Format

Description

Regex

FIELD REGEX

Keep records which field matches the regular expression.

Exclude

FIELD REGEX

Exclude records which field matches the regular expression.

Getting Started

In order to start filtering records, you can run the filter from the command line or through the configuration file. The following example assumes that you have a file called lines.txt with the following content

aaa
aab
bbb
ccc
ddd
eee
fff
ggg

Command Line

Note: using the command line mode need special attention to quote the regular expressions properly. It's suggested to use a configuration file.

The following command will load the tail plugin and read the content of lines.txt file. Then the grep filter will apply a regular expression rule over the log field (created by tail plugin) and only pass the records which field value starts with aa:

$ bin/fluent-bit -i tail -p 'path=lines.txt' -F grep -p 'regex=log aa' -m '*' -o stdout

Configuration File

[INPUT]
Name tail
Path lines.txt
[FILTER]
Name grep
Match *
Regex log aa
[OUTPUT]
Name stdout
Match *

The filter allows to use multiple rules which are applied in order, you can have many Regex and Exclude entries as required.