Buffer section does not accept arguments

[MaxAnderson95]

I just extended the logging-operator project to support this plugin for Logicmonitor (See this PR). However I've discovered, that the fluent config that logging-operator generates is incompatible with this plugin. Specifically as it relates to the buffer section.

The logging-operator generates a config similar to this:

<match **>
    @type lm
    @id flow:quickstart:log-generator:output:quickstart:lm
    access_id REDACTED
    access_key REDACTED
    company_domain logicmonitor.com
    company_name REDACTED
    flush_interval 30s
    include_metadata true
    <buffer tag,time>
      @type file
      path /buffers/flow:quickstart:log-generator:output:quickstart:lm.*.buffer
      retry_forever true
      timekey 10m
      timekey_wait 1m
    </buffer>
</match>

Notice the arguments of tag and time being passed to buffer. This causes the following error on config validation:

2025-06-06 15:49:24 +0000 [error]: config error file="/fluentd/etc/fluent.conf" error_class=Fluent::ConfigError error="this plugin 'Fluent::LmOutput' cannot handle arguments for <buffer ...> section"

I believe this is caused by the use of the old 0.12 fluentd plugin syntax still in use here:

module Fluent
  class LmOutput < BufferedOutput

According to the documentation for developing an output plugin in fluentd 1.0, you're supposed to extend the Fluent::Plugin::Output Class, and then implement the def write(chunk) method to handle buffering.

The gemspec already requires fluentd 1.0, so I think this change is safe to make.

Can the plugin be updated to support this new syntax?

[MaxAnderson95]

@vishaalcharpe @choudharypooja