[logstash-input-http] 插件使用详解

http {}

http{
    host => "0.0.0.0"
    port => 8080
    additional_codecs => {"application/json"=>"json"}
    codec => "plain"
    threads => 4
    ssl => false
}

public
  def register
    # register方法相当于初始化的构造方法
  end # def register

  # 主要的核心业务方法都在run中
  def run(queue)
    Stud.interval(@interval) do
      # 创建事件
      event = LogStash::Event.new("message" => @message, "host" => @host)
      # 装饰event对象
      decorate(event)
      # 放入队列中
      queue << event
    end # loop
  end # def run

 def register
    require "logstash/util/http_compressed_requests"
    # 创建Puma服务器
    @server = ::Puma::Server.new(nil) # we'll set the rack handler later
    # 下面的都是跟认证相关的....
    if @user && @password then
      token = Base64.strict_encode64("#{@user}:#{@password.value}")
      @auth_token = "Basic #{token}"
    end
    if @ssl
      if @keystore.nil? || @keystore_password.nil?
        raise(LogStash::ConfigurationError, "Settings :keystore and :keystore_password are required because :ssl is enabled.")
      end
      ctx = Puma::MiniSSL::Context.new
      ctx.keystore = @keystore
      ctx.keystore_pass = @keystore_password.value
      ctx.verify_mode = case @verify_mode
                        when 'peer'
                          Puma::MiniSSL::VERIFY_PEER
                        when 'force_peer'
                          Puma::MiniSSL::VERIFY_PEER | Puma::MiniSSL::VERIFY_FAIL_IF_NO_PEER_CERT
                        when 'none'
                          Puma::MiniSSL::VERIFY_NONE
                        end
      @server.add_ssl_listener(@host, @port, ctx)
    else
      @server.add_tcp_listener(@host, @port)
    end
    # 设置线程的数量
    @server.min_threads = 0
    @server.max_threads = @threads
    @codecs = Hash.new
    # 创建文本类型对应的codecs映射
    @additional_codecs.each do |content_type, codec|
      @codecs[content_type] = LogStash::Plugin.lookup("codec", codec).new
    end
  end # def register

def run(queue)
    p = Proc.new do |req|
      begin
        remote_host = req['puma.socket'].peeraddr[3]
        REJECTED_HEADERS.each {|k| req.delete(k) }
        req = lowercase_keys(req)
        body = req.delete("rack.input")
        # 这里使用相应的codec解析对应的Body信息
        @codecs.fetch(req["content_type"], @codec).decode(body.read) do |event|
          # 这里遍历每个事件，然后添加host和headers信息
          event["host"] = remote_host
          event["headers"] = req
          decorate(event)
          queue << event
        end
        # 如果正常处理，则返回ok
        ['200', @response_headers, ['ok']]
      rescue => e
        @logger.error("unable to process event #{req.inspect}. exception => #{e.inspect}")
        ['500', @response_headers, ['internal error']]
      end
    end

    auth = Proc.new do |username, password|
      username == @user && password == @password.value
    end if (@user && @password)

    @server.app = Rack::Builder.new do
      use(Rack::Auth::Basic, &auth) if auth
      use CompressedRequests
      run(p)
    end
    @server.run.join
  end

  private
  def lowercase_keys(hash)
    new_hash = {}
    hash.each_pair do |k,v|
      new_hash[k.downcase] = v
    end
    new_hash
  end