Class: LogStash::Filters::ZeroMQ

Inherits:
Base show all
Defined in:
lib/logstash/filters/zeromq.rb

Overview

ZeroMQ filter. This is the best way to send an event externally for filtering It works much like an exec filter would by sending the event “offsite” for processing and waiting for a response

The protocol here is:

* REQ sent with JSON-serialized logstash event
* REP read expected to be the full JSON 'filtered' event
* - if reply read is an empty string, it will cancel the event.

Note that this is a limited subset of the zeromq functionality in inputs and outputs. The only topology that makes sense here is: REQ/REP.

Constant Summary

Constants inherited from Base

Base::RESERVED

Constants included from Config::Mixin

Config::Mixin::CONFIGSORT

Instance Attribute Summary

Attributes included from Config::Mixin

#config, #original_params

Attributes inherited from Plugin

#logger, #params

Instance Method Summary collapse

Methods inherited from Base

#execute, #threadsafe?

Methods included from Config::Mixin

#config_init, included

Methods inherited from Plugin

#eql?, #finished, #finished?, #hash, #inspect, lookup, #reload, #running?, #shutdown, #teardown, #terminating?, #to_s

Constructor Details

#initialize(params) ⇒ ZeroMQ

Returns a new instance of ZeroMQ.



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# File 'lib/logstash/filters/zeromq.rb', line 55

def initialize(params)
  super(params)

  @threadsafe = false
end

Instance Method Details

#filter(event) ⇒ Object 



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# File 'lib/logstash/filters/zeromq.rb', line 80

def filter(event)
  return unless filter?(event)

  # TODO (lusis)
  # Need to set a timeout on the socket
  # If it never gets a reply, filtering stops cold
  begin
    if @field
      @logger.debug("0mq: sending", :request => event[@field])
      error_check(@zsocket.send_string(event[@field]), "in send_string")
    else
      @logger.debug("0mq: sending", :request => event.to_json)
      error_check(@zsocket.send_string(event.to_json), "in send_string")
    end
    reply = ''
    rc = @zsocket.recv_string(reply)
    error_check(rc, "in recv_string")

    # If we receive an empty reply, this is an indication that the filter
    # wishes to cancel this event.
    if reply.empty?
      event.cancel
      return
    end
    @logger.debug("0mq: receiving", :reply => reply)
    if @field
      event[@field] = event.sprintf(reply)
      filter_matched(event)
    else
      reply = JSON.parse(reply)
      event.overwrite(reply)
    end
    filter_matched(event)
  rescue => e
    @logger.warn("0mq filter exception", :address => @address, :exception => e, :backtrace => e.backtrace)
  end
end

#register ⇒ Object 



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# File 'lib/logstash/filters/zeromq.rb', line 62

def register
  require "ffi-rzmq"
  require "logstash/util/zeromq"
  self.class.send(:include, LogStash::Util::ZeroMQ)

  @zsocket = context.socket(ZMQ::REQ)

  error_check(@zsocket.setsockopt(ZMQ::LINGER, 1),
              "while setting ZMQ::LINGER == 1)")

  if @sockopt
    setopts(@zsocket, @sockopt)
  end

  setup(@zsocket, @address)
end