mailer-handler.rb - TCP Mailer handler for Sensu

gistfile1.txt

#!/opt/sensu/embedded/bin/ruby

# A TCP Mailer handler for Sensu, based on https://github.com/sensu/sensu-community-plugins/blob/master/handlers/notification/mailer.rb.
#
# This expects the email address to be defined with an 'mail_to' attribute in the check,
# so different checks can send to different addresses.
#
# Requires sensu-generichandler.rb (https://gist.github.com/b-boyd/d52abc1c3baf6ea9e33d)
# and expects it in "../lib/". This mailer-handler.rb can be copied to
# /opt/sensu/handler/bin/.
#
# Example handler configuration, mailer.json:
# {
#   "mailer": {
#     "smtp_domain": "mydomain.com",
#     "mail_from": "sensu@mydomain.com",
#     "smtp_port": 25,
#     "smtp_address": "smtp.mydomain.com"
#   },
#   "handlers": {
#     "mailer": {
#       "severities": [
#         "ok",
#         "warning",
#         "critical",
#         "unknown"
#       ],
#       "type": "tcp",
#       "socket": {
#         "port": 2035,
#         "host": "127.0.0.1"
#       }
#     }
#   }
# }
#
# Don't forget an init script (https://gist.github.com/b-boyd/821433dd903fd45d998e)
# and to rotate/purge the /var/log/sensu/sensu-mailer-handler.log file.
#
# Add a sensu check to ensure the process is running and/or the port is listening
# and use the remediator handler to automatically restart.

$LOAD_PATH.unshift(File.dirname(__FILE__) + '/../lib')

require 'rubygems'
require 'sensu/cli'
require 'sensu/base'
require 'sensu-generichandler'
gem 'mail', '~> 2.5.4'
require 'mail'
require 'timeout'


class MailerServer

  $STOP_SIGNALS = %w[INT TERM]

  def self.run(options={})
    server = self.new(options)
    EM.run do
      server.start
      server.trap_signals
    end
  end

  def initialize(options={})
    base = Sensu::Base.new(options)
    base.setup_process
    @logger = base.logger
    @settings = base.settings
  end

  def start
    begin
      host = @settings['handlers']['mailer']['socket']['host']
    rescue
      @logger.error("@settings['handlers']['mailer']['socket']['host'] not defined")
      return
    end

    begin
      port = @settings['handlers']['mailer']['socket']['port'].to_i
    rescue
      @logger.error("@settings['handlers']['mailer']['socket']['port'] not defined")
      return
    end

    mailer_client = MailerClient.new

    EM.start_server(host, port, MailerReceiver) do |conn|
      conn.handler = mailer_client
      conn.logger = @logger
    end
  end

  def trap_signals
    @signals = Array.new
    $STOP_SIGNALS.each do |signal|
      Signal.trap(signal) do
        @signals << signal
      end
    end
    EM::PeriodicTimer.new(1) do
      signal = @signals.shift
      if $STOP_SIGNALS.include?(signal)
        @logger.warn('received signal', {
          :signal => signal
        })
        EM.stop
      end
    end
  end
end

# Receive data over a socket that should go to Mail
class MailerReceiver < EM::Connection
  attr_accessor :handler
  attr_accessor :logger

  def receive_data(data)
    begin
      handler.handle(data, logger)
    rescue Exception => e
      logger.info(e.message)
    end

    close_connection
  end
end

class MailerClient < Sensu::GenericHandler
  @event
  @logger

  def handle(data, logger)
    @logger = logger

    if ! is_json?(data)
      @logger.error("Invalid JSON data - #{data}")
      return
    end

    @event = JSON.parse(data)
    self.filter

    client = @event['client']['name']
    output = @event['check']['output']

    send_email(client, output)
  end

  def send_email(client, output)
    # If a 'mail_to' isn't defined for this check
    if ! @event['check']['mail_to']
      @logger.info("No mail_to defined")
      return
    end

    mail_to = @event['check']['mail_to']
    mail_from =  settings['mailer']['mail_from']

    smtp_address = settings['mailer']['smtp_address'] || 'localhost'
    smtp_port = settings['mailer']['smtp_port'] || '25'
    smtp_domain = settings['mailer']['smtp_domain'] || 'localhost.localdomain'

    smtp_username = settings['mailer']['smtp_username'] || nil
    smtp_password = settings['mailer']['smtp_password'] || nil
    smtp_authentication = settings['mailer']['smtp_authentication'] || :plain

    if @event['check']['status'] == 0
      status = "RESOLVED"
    elsif @event['check']['status'] == 1
      status = "WARNING"
    elsif @event['check']['status'] == 2
      status = "CRITICAL"
    else
      status = "UNKNOWN"
    end

    subject = "#{status} - " + @event['check']['name'] + " on #{client}"

    text_body = "#{output}\n\n"
    text_body += <<-BODY
Host: #{@event['client']['name']}
Check Name:  #{@event['check']['name']}
Timestamp: #{Time.at(@event['check']['issued'])}
Command:  #{@event['check']['command']}
Occurrences:  #{@event['occurrences']}
BODY

    html_body = "<b>#{output}</b><br><br>"
    html_body += <<-BODY
Host: #{@event['client']['name']}<br>
Timestamp: #{Time.at(@event['check']['issued'])}<br>
Check Name:  #{@event['check']['name']}<br>
Command:  #{@event['check']['command']}<br>
Occurrences:  #{@event['occurrences']}<br>
BODY

    Mail.defaults do
      delivery_options = {
        :address    => smtp_address,
        :port       => smtp_port,
        :domain     => smtp_domain,
        :openssl_verify_mode => 'none',
        :enable_starttls_auto => true
      }

      unless smtp_username.nil?
        auth_options = {
          :user_name        => smtp_username,
          :password         => smtp_password,
          :authentication   => smtp_authentication
        }
        delivery_options.merge! auth_options
      end

      delivery_method :smtp, delivery_options
    end

    begin
      timeout 10 do
        Mail.deliver do
          to      mail_to
          from    mail_from
          subject subject

          text_part do
            body text_body
          end

          html_part do
            content_type 'text/html; charset=UTF-8'
            body html_body
          end
        end

        @logger.info('mail -- sent alert for ' + short_name + ' to ' + mail_to.to_s)
      end
    rescue Timeout::Error
      @logger.error('mail -- timed out while attempting to ' + @event['action'] + ' an incident -- ' + short_name)
    end
  end

  def short_name
    @event['client']['name'] + '/' + @event['check']['name']
  end

  def bail(msg)
    raise msg + ': ' + @event['client']['name'] + '/' + @event['check']['name']
  end

  def is_json?(str)
    begin
      !!JSON.parse(str)
    rescue
      false
    end
  end
end


begin
  options = Sensu::CLI.read
  MailerServer.run(options)
rescue exit
rescue Exception => e
  @logger.error("#{e}. #{e.backtrace}")
end