CouchDB replication

monitor_replication.rb

#!/usr/bin/env ruby

#Start CouchDB replication with
#curl -X POST -d '{"source":"https://user:passwd@src_ip:6984/source_db", "target":"https://user:passwd@dst_ip:6984/dst_db", continuous:true}' -H 'Content-Type: application/json' https://host:6984/_replicator


# This script checks a list of databases that should be replicating and their last replication time. 
# If the replication hasn't been updated in an hour, an email is sent to 'email@example.com' 
# with the subject 'CouchDB replication problem'.


#'/etc/couchdb/monitoring-config.json'
#{
#  "protocol": "http",
#  "host":"myhost.com",
#  "port":5984,
#  "user":"db_user",
#  "password":"XXXXX",
#
#
#  "smtp_host":"smtp.example.com",
#  "smtp_port":587,
#  "smtp_user_name":"email@example.com",
#  "smtp_password":"xxxxxx"
#}



require "rubygems"
require "json"
require "mail"

LAST_UPDATE_LIMIT_IN_SECONDS=3600
REPLICATED_DB=["mydb", "yourdb", "ourdb"]


def check_replication(task)
  source = task['source']
  target = task['target']
  updated_on = task['updated_on']

  return false unless target.include? source

  return false unless (Time.now.to_i - updated_on) > LAST_UPDATE_LIMIT_IN_SECONDS

  true
end

def send_email(config, msg)
  options = {
            :address              => config['smtp_host'],
            :port                 => config['smtp_port'],
            :domain               => 'example.com',
            :user_name            => config['smtp_user_name'],
            :password             => config['smtp_password'],
            :authentication       => 'plain',
            :enable_starttls_auto => true  }

  Mail.defaults do
    delivery_method :smtp, options
  end
  Mail.deliver do
    to 'email@example.com'
    from 'DBA@example.com'
    subject 'CouchDB replication problem'
    body "#{msg}"
  end
end


config = JSON.parse(File.read('/etc/couchdb/monitoring-config.json'))

url="#{config['protocol']}://#{config['user']}:#{config['password']}@#{config['host']}:#{config['port']}/_active_tasks"
string = `curl -s #{url}`
tasks = JSON.parse(string)
databases = REPLICATED_DB.dup

message = ""
tasks.each { |t|
  next unless t['type'] == 'replication'

  databases.delete(t['source'])

  next unless check_replication(t)
  message << sprintf("Replication task [%s] doesn't look right:\n", t['replication_id'])
  message << sprintf(" source:'%s' target:'%s'\n", t['source'], t['target'])
  message << sprintf(" last update %d s ago\n", Time.now.to_i - t['updated_on'])
  message << sprintf(" %s\n\n",t)
}

message << "Couldn't find replication for #{databases}" unless databases.empty?

if !message.empty?
  #`logger -s "CouchDB replication: #{message}"`
  send_email(config, message)
end