newrelic_wikipedia_agent

#!/usr/bin/env ruby
require "rubygems"
require "bundler/setup"
require "newrelic_plugin"
require "net/http"

#
#
# The entire agent should be enclosed in a "WikipediaAgent" module
#
#
module WikipediaAgent

  #
  # Agent, Metric and PollCycle classes
  #
  # Each agent module must have an Agent, Metric and PollCycle class that inherits from their
  # Component counterparts as you can see below.
  #
  class Agent < NewRelic::Plugin::Agent::Base

    agent_guid   "com.newrelic.examples.wikipedia"
    agent_version "1.0.4"

    #
    # Each agent class must also include agent_human_labels. agent_human_labels requires:
    # A friendly name of your component to appear in graphs.
    # A block that returns a friendly name for this instance of your component.
    #
    # The block runs in the context of the agent instance.
    #
    agent_human_labels("Wikipedia") { "Wikipedia #{hostname}" }


    #
    # agent_config is a list of variables that the component will need
    # from its instances. The Wikipedia agent is asking for the
    # hostname to get the information from which it uses when it asks for the data.
    #
    agent_config_options :hostname

    def setup_metrics
      @WIKIPEDIA_STAT_URL = URI.parse("http://#{hostname}/w/api.php?action=query&format=json&meta=siteinfo&siprop=statistics")
      @article_creation_rate = NewRelic::Processor::EpochCounter.new
    end


    def poll_cycle
      num_articles = get_num_articles
      if num_articles
        report_metric("Articles/Created", "articles/sec", @article_creation_rate.process(num_articles))
        report_metric("Articles/Count", "articles", num_articles)
      end
    end

    private

    def get_num_articles
      begin
        resp = ::Net::HTTP.get_response(@WIKIPEDIA_STAT_URL)
      rescue
        return nil
      end
      data = resp.body

      begin
        result = JSON.parse(data)  # if server unavailable, then data may be html, not json
      rescue
        return nil
      end
      puts "returning #{result['query']['statistics']['articles']} total articles"
      result['query']['statistics']['articles']
    end
  end


  NewRelic::Plugin::Setup.install_agent :wikipedia,WikipediaAgent


  #
  # Launch the agent (never returns)
  #
  NewRelic::Plugin::Run.setup_and_run

end