fluentd の plugin ごとの buffer_total_queued_size と buffer 使用率を出力する

fluentd_buffer_stats.rb

#!/usr/bin/env ruby

require "net/http"
require "uri"
require "json"
require "optparse"

@args = {}
OptionParser.new do |opt|
  opt.on("-p PORT", "--port PORT", "Port"){|v| @args[:port] = v }
  opt.on("--plugin-id ID", "Plugin ID"){|v| @args[:plugin_id] = v }
  opt.on("--chunk-limit CHUNK_LIMIT", "Default buffer chunk limit (bytes)"){|v| @args[:chunk_limit] = v }
  opt.on("--queue-limit QUEUE_LIMIT", "Default buffer queue limit"){|v| @args[:queue_limit] = v }
  opt.on("--retry-limit", "Default retry limit"){|v| @args[:retry_limit] = v }
  opt.parse!(ARGV)
end

if @args[:plugin_id].nil?
  puts "--plugin-id is required"
  exit 1
end

@args[:port] ||= 24220
@args[:chunk_limit] ||= 8 * (1024 ** 2)
@args[:queue_limit] ||= 256
@args[:retry_limit] ||= 17

def chunk_limit(bytes_str)
  return @args[:chunk_limit] if bytes_str.nil?

  case
  when bytes_str.include?("k")
    bytes_str.delete("k").to_i * 1024
  when bytes_str.include?("m")
    bytes_str.delete("m").to_i * (1024 ** 2)
  when bytes_str.include?("g")
    bytes_str.delete("g").to_i * (1024 ** 3)
  end
end

uri = URI.parse("http://localhost:#{@args[:port]}/api/plugins.json")
body = Net::HTTP.get(uri)
plugins = JSON.parse(body)

plugins["plugins"].each do |plugin|
  next unless plugin["plugin_category"] == "output"
  next unless plugin["config"]["@id"] == @args[:plugin_id]
  queued_size = plugin["buffer_total_queued_size"].to_i
  chunk_limit = chunk_limit(plugin["config"]["buffer_chunk_limit"])
  queue_limit = plugin["config"]["buffer_queue_limit"].to_i || @args[:queue_limit]
  retry_limit = plugin["config"]["retry_limit"].to_i || @args[:retry_limit]
  retry_count = plugin["retry_count"].to_i
  puts "#{queued_size} #{(queued_size / (chunk_limit * queue_limit)) * 100} #{(retry_count / retry_limit) * 100}"
end

usage.md

$ fluentd_buffer_stats.rb --help
Usage: fluentd_buffer_stats [options]
    -p, --port PORT                  Port
        --plugin-id ID               Plugin ID
        --chunk-limit CHUNK_LIMIT    Default buffer chunk limit (bytes)
        --queue-limit QUEUE_LIMIT    Default buffer queue limit
        --retry-limit                Default retry limit