A nagios plugin ruby script to monitor solr cloud cluster

solr_monitor.rb

####
#  Description:a nagios plugin script to monitor solr cloud cluster
#  Requirements: zookeeper
#                sudo gem install zookeeper
#                sudo gem install rsolr
#
#####
require 'rubygems'
require 'zookeeper'
require 'rsolr'

class SolrCloudMonitor

  def initialize(zk_servers, query_path , expect_nodes_count)
    @zk = Zookeeper.new(zk_servers)
    @query_path = query_path || "select"
    @expect_nodes_count = expect_nodes_count
  end

  def run
    #check if live nodes number is right.
    live_nodes = safe_zk_get_children("/live_nodes")[:children]
    return "Expect #{@expect_nodes_count} live nodes,actual #{live_nodes.size}.",2 if live_nodes.size != @expect_nodes_count
    #try query some text using rsolr
    errors = []
    live_nodes.each do |node|
      if node =~ /(.*)_solr$/
        server = $1
        solr = RSolr.connect :url => "http://#{server}/solr" , :read_timeout => 5, :open_timeout => 5
        response = solr.get @query_path, :params => {:q => '*:*', :start=>0, :rows=>10}
        errors << "Query solr server:#{server} failed" if response["response"]["docs"].nil? or response["response"]["docs"].size == 0
      end
    end
    if errors.size > 0
      return errors.join("\r\n"),2
    else
      return nil,0
    end
  end

  def close
    safe_zk_close
  end

  private
  def safe_zk_close()
    begin
      @zk.close() if @zk
    rescue
      #ignore
    end
  end

  def safe_zk_get_children(path, watcher=nil, count=0)
    begin
      return @zk.get_children({:path => path, :watcher => watcher })
    rescue Exception => e
      if count >= 3
        raise e
      else
        safe_zk_close()
        @zk = Zookeeper.new(@zk_servers)
        return safe_zk_get_children(path, watcher, count.succ)
      end
    end
  end
end

if __FILE__ == $0
  begin
    #We expect six live nodes and use /select for querying.
    monitor = SolrCloudMonitor.new("zk1:2181,zk2:2181,zk3:2181", "select" , 6)
    error, code = monitor.run
    monitor.close
    puts error if error
    exit code
  rescue =>e
    puts e.backtrace
    puts e.message
    exit 3
  end
end