CheckList

The CheckList plugin (introduced in version 1.8.4) looks up a value in a specified list to see if it exists. The plugin then allows the addition of a record to indicate if the value was found.

Configuration parameters

The plugin supports the following configuration parameters

Key	Description	Default
file	The single value file that Fluent Bit will use as a lookup table to determine if the specified lookup_key exists.	none
lookup_key	The specific key to look up and determine if it exists. Supports record accessor.	none
record	The record to add if the lookup_key is found in the specified file. You can add multiple record parameters.	none
mode	Set the check mode. exact and partial are supported.	exact
print_query_time	Print to stdout the elapsed query time for every matched record.	false
ignore_case	Compare strings by ignoring case.	false

Example configuration

fluent-bit.yaml

pipeline:
    inputs:
        - name: tail
          tag: test1
          path: test1.log
          read_from_head: true
          parser: json
    
    filters:
        - name: checklist
          match: test1
          file: ip_list.txt
          lookup_key: $remote_addr
          record:
              - ioc abc
              - badurl null
          log_level: debug
    
    outputs:
        - name: stdout
          match: test1

fluent-bit.conf

[INPUT]
    name           tail
    tag            test1
    path           test1.log
    read_from_head true
    parser         json

[FILTER]
    name       checklist
    match      test1
    file       ip_list.txt
    lookup_key $remote_addr
    record     ioc    abc
    record     badurl null
    log_level  debug

[OUTPUT]
    name       stdout
    match      test1

The following configuration reads a file test1.log that includes the following values:

{"remote_addr": true, "ioc":"false", "url":"https://badurl.com/payload.htm","badurl":"no"}
{"remote_addr": "7.7.7.2", "ioc":"false", "url":"https://badurl.com/payload.htm","badurl":"no"}
{"remote_addr": "7.7.7.3", "ioc":"false", "url":"https://badurl.com/payload.htm","badurl":"no"}
{"remote_addr": "7.7.7.4", "ioc":"false", "url":"https://badurl.com/payload.htm","badurl":"no"}
{"remote_addr": "7.7.7.5", "ioc":"false", "url":"https://badurl.com/payload.htm","badurl":"no"}
{"remote_addr": "7.7.7.6", "ioc":"false", "url":"https://badurl.com/payload.htm","badurl":"no"}
{"remote_addr": "7.7.7.7", "ioc":"false", "url":"https://badurl.com/payload.htm","badurl":"no"}

Additionally, it uses the following lookup file which contains a list of malicious IP addresses (ip_list.txt).

1.2.3.4
6.6.4.232
7.7.7.7

The configuration uses $remote_addr as the lookup key, and 7.7.7.7 is malicious. The record output for the last record would look like the following:

{"remote_addr": "7.7.7.7", "ioc":"abc", "url":"https://badurl.com/payload.htm","badurl":"null"}