Add basic fleuntd management

app/controllers/fluentd_controller.rb

@@ -0,0 +1,34 @@
+class FluentdController < ApplicationController
+  before_filter :fluentd
+
+  def index
+  end
+
+  def status
+  end
+
+  def start
+    fluentd.start
+    render :status
+  end
+
+  def stop
+    fluentd.stop
+    render :status
+  end
+
+  def reload
+    fluentd.reload
+    render :status
+  end
+
+  def log
+    render text: fluentd.log, content_type: "text/plain"
+  end
+
+  private
+
+  def fluentd
+    @fluentd ||= Fluentd.new(Rails.root + "tmp" + "fluentd")
+  end
+end

app/models/fluentd.rb

@@ -0,0 +1,109 @@
+Bundler.require(:default, :development)
+
+require 'fluent/log'
+require 'fluent/env'
+require 'fluent/version'
+require 'fluent/supervisor'
+
+class Fluentd
+  attr_reader :root_dir
+
+  def initialize(root_dir)
+    @root_dir = root_dir
+    FileUtils.mkdir_p @root_dir
+  end
+
+  def pid_file
+    File.join(root_dir, "fluentd.pid")
+  end
+
+  def pid
+    return unless File.exists?(pid_file)
+    File.read(pid_file)
+  end
+
+  def log_file
+    File.join(root_dir, "fluentd.log")
+  end
+
+  def config_file
+    file = File.join(root_dir, "fluentd.conf")
+    unless File.exists?(file)
+      File.open(file, "w") {|f| f.write "<source>\ntype forward\n</source>" } # TODO
+    end
+    file
+  end
+
+  def plugin_dir
+    dir = File.join(root_dir, "fluentd", "plugins")
+    unless Dir.exist?(dir)
+      FileUtils.mkdir_p(dir)
+    end
+    dir
+  end
+
+  def options
+    # TODO: https://github.com/fluent/fluentd/pull/315
+    {
+      :config_path => Fluent::DEFAULT_CONFIG_PATH,
+      :plugin_dirs => [Fluent::DEFAULT_PLUGIN_DIR],
+      :log_level => Fluent::Log::LEVEL_INFO,
+      :log_path => nil,
+      :daemonize => false,
+      :libs => [],
+      :setup_path => nil,
+      :chuser => nil,
+      :chgroup => nil,
+      :suppress_interval => 0,
+      :suppress_repeated_stacktrace => false,
+      :use_v1_config => false,
+    }.merge({
+      :use_v1_config => true,
+      :plugin_dirs => [plugin_dir],
+      :config_path => config_file,
+      :daemonize => pid_file,
+      :log_path => log_file,
+      :log_level => Fluent::Log::LEVEL_INFO,
+    })
+  end
+
+  def running?
+    pid && system("/bin/kill -0 #{pid}", :out => File::NULL, :err => File::NULL)
+  end
+
+  def start
+    return if running?
+    spawn("bundle exec fluentd #{options_to_argv(options)}") # TODO
+  end
+
+  def stop
+    return unless running?
+    system("/bin/kill -TERM #{pid}")
+    File.unlink(pid_file)
+  end
+
+  def reload
+    return unless running?
+    system("/bin/kill -HUP #{pid}")
+  end
+
+  def log
+    File.read log_file # TODO: large log file
+  end
+
+  def config
+    File.read config_file # TODO: Use Fluent::Engine or Fluent::V1Config
+  end
+
+  private
+
+  def options_to_argv(options)
+    argv = ""
+    argv << " --use-v1-config" if options[:use_v1_config]
+    argv << " -c #{options[:config_path]}" if options[:config_path].present?
+    argv << " -p #{options[:plugin_dir].first}" if options[:plugin_dir].present?
+    argv << " -d #{options[:daemonize]}" if options[:daemonize].present?
+    argv << " -o #{options[:log_path]}" if options[:log_path].present?
+    argv
+  end
+end

app/views/fluentd/index.html.haml

@@ -0,0 +1,7 @@
+%h1
+  = @fluentd.running? ? "running" : "stopped"
+
+  = link_to "start", start_fluentd_path(id: 1), method: :put, remote: true
+  = link_to "stop", stop_fluentd_path(id: 1), method: :put
+  = link_to "reload", reload_fluentd_path(id: 1), method: :put
+  = link_to "log", log_fluentd_path(id: 1)

app/views/fluentd/status.html.haml

@@ -0,0 +1,8 @@
+
+%h1
+  = @fluentd.running? ? "running" : "stopped"
+
+  = link_to "start", start_fluentd_path(id: 1), method: :put, remote: true
+  = link_to "stop", stop_fluentd_path(id: 1), method: :put
+  = link_to "reload", reload_fluentd_path(id: 1), method: :put
+  = link_to "log", log_fluentd_path(id: 1)

config/routes.rb

@@ -1,4 +1,20 @@
 Rails.application.routes.draw do
+  resources :fluentd, only: [:index] do
+    member do
+      get "status"
+      put "start"
+      put "stop"
+      put "reload"
+      get "log"
+      resource :config do
+      end
+    end
+  end
+  resources :plugins do
+  end
+
+  resources :misc, only: [] do
+  end
   # The priority is based upon order of creation: first created -> highest priority.
   # See how all your routes lay out with "rake routes".