+#!/usr/bin/ruby
+
+# Copyright (c) 2004, 2005, 2006, 2007 Peter Palfrader <peter@palfrader.org>
+
+require "yaml"
+
+ORG="relativity"
+SHORTORG="rela"
+CONTACTGROUP="weaselgroup"
+GENERATED_PREFIX="/etc/NOREPLY/generated/nagios/"
+
+nagios_filename = {};
+%w(hosts hostgroups services dependencies hostextinfo serviceextinfo).each{
+ |x| nagios_filename[x] = GENERATED_PREFIX+"auto-#{x}.cfg"
+}
+nagios_filename['nrpe'] = GENERATED_PREFIX+"nrpe_#{ ORG }.cfg"
+
+
+MAX_CHECK_ATTEMPTS_DEFAULT=6
+
+NRPE_CHECKNAME="#{ ORG }_check_nrpe" # check that takes one argument: service name to be checked
+NRPE_CHECKNAME_HOST="#{ ORG }_check_nrpe_host" # check that takes two arguments: relay host on which to run check, service name to be checked
+
+HOST_TEMPLATE_NAME='generic-host' # host templates that all our host definitions use
+SERVICE_TEMPLATE_NAME='generic-service' # host templates that all our host definitions use
+HOST_ALIVE_CHECK='check-host-alive' # host alive check if server is pingable
+NRPE_PROCESS_SERVICE='process - nrpe' # nrpe checks will depend on this one
+
+
+def warn (msg)
+ STDERR.puts msg
+end
+def set_if_unset(hash, key, value)
+ hash[key] = value unless hash.has_key?(key)
+end
+def set_complain_if_set(hash, key, value, type, name)
+ throw "#{type} definition '#{name}' has '#{key}' already defined" if hash.has_key?(key)
+ hash[key] = value
+end
+
+# Make an array out of something. If there is nothing, create an empty array
+# if it is just a string, make a list with just that element, if it already is
+# an array keep it.
+def ensure_array(something)
+ if (something == nil)
+ result = []
+ elsif something.kind_of?(String)
+ result = [ something ]
+ elsif something.kind_of?(Array)
+ result = something
+ else
+ throw "Do now know how to make an array out of #{something}: " + something.to_yaml
+ end
+ return result
+end
+
+
+# This class keeps track of the checks done via NRPE and makes sure
+# each gets a unique name.
+#
+# Unforutunately NRPE limits check names to some 30 characters, so
+# we need to mangle service names near the end.
+class Nrpe
+ def initialize
+ @checks = {}
+ end
+
+ def make_name( name, check )
+ name = name.tr_s("^a-zA-Z", "_").gsub("process", "ps")
+
+ result = "#{ SHORTORG }_" + name[0,19]
+
+ hash = ''
+ skew = ''
+ while (@checks.has_key?(result + hash))
+ # hash it, so that we don't lose uniqeness by cutting it off
+ hash = (check+skew).crypt("$1$")
+ hash = hash[-5,5] # 5 chars are enough
+ hash.tr!("/", "_")
+ skew += ' ' # change it a bit so the hash changes
+ end
+ result += hash
+ return result # max of 32 or so chars
+ end
+
+ def add( name, check )
+ if @checks.has_value? check
+ @checks.each_pair{ |key, value|
+ return key if value == check
+ }
+ end
+ key = make_name(name, check)
+ @checks[ key ] = check
+ return key
+ end
+
+ def checks
+ return @checks
+ end
+end
+$nrpe = Nrpe.new()
+
+
+# Prints the keys and values of hash to a file
+# This is the function that prints the bodies of most our
+# host/service/etc definitions
+#
+# It skips over such keys as are listed in exclude_keys
+# and also skips private keys (those starting with an underscre)
+def print_block(fd, kind, hash, exclude_keys)
+ fd.puts "define #{kind} {"
+ hash.each_pair{ |key, value|
+ next if key[0,1] == '_'
+ next if exclude_keys.include? key
+ fd.puts " #{key} #{value}"
+ }
+ fd.puts "}"
+ fd.puts
+end
+
+
+# Add the service definition service to hosts
+# f is the file for service definitions, deps the file for dependencies
+def addService(hosts, service, files)
+
+ set_if_unset service, 'use' , SERVICE_TEMPLATE_NAME
+ set_complain_if_set service, 'host_name' , hosts.join(',') , 'Service', service['service_description']
+ set_if_unset service, 'max_check_attempts', MAX_CHECK_ATTEMPTS_DEFAULT
+
+ service['max_check_attempts'] = MAX_CHECK_ATTEMPTS_DEFAULT + service['max_check_attempts'] if service['max_check_attempts'] < 0
+
+ if service['nrpe']
+ throw "We already have a check_command (#{service['check_command']}) but we are in the NRPE block (nrpe: #{service['nrpe']})."+
+ " This should have been caught much earlier" if service.has_key?('check_command');
+
+ check = $nrpe.add(service['service_description'], service['nrpe'])
+ service['check_command'] = "#{ NRPE_CHECKNAME }!#{ check }"
+
+ service['depends'] = ensure_array( service['depends'] )
+ service['depends'] << NRPE_PROCESS_SERVICE unless service['service_description'] == NRPE_PROCESS_SERVICE # Depend on NRPE unless we are it
+ end
+
+ print_block files['services'], 'service', service, %w(nrpe runfrom remotecheck
+ depends
+ hosts hostgroups excludehosts excludehostgroups)
+
+ if service['depends']
+ service['depends'].each{ |prerequisite|
+ hosts.each{ |host|
+ prerequisite_host = host
+ pre = prerequisite
+ # split off a hostname if there's one
+ bananasplit = prerequisite.split(':')
+ if bananasplit.size == 2
+ prerequisite_host = bananasplit[0]
+ pre = bananasplit[1]
+ elsif bananasplit.size > 2
+ throw "Cannot prase prerequisite #{prerequisite} for service #{service['service_description']} into host:service"
+ end
+ dependency = {
+ 'host_name' => prerequisite_host,
+ 'service_description' => pre,
+ 'dependent_host_name' => host,
+ 'dependent_service_description' => service['service_description'],
+ 'execution_failure_criteria' => 'n',
+ 'notification_failure_criteria' => 'w,u,c'
+ };
+ print_block files['dependencies'], 'servicedependency', dependency, %w()
+ }
+ }
+ end
+
+
+ set_complain_if_set service['_extinfo'], 'service_description' , service['service_description'], 'serviceextinfo', service['service_description']
+ set_complain_if_set service['_extinfo'], 'host_name' , hosts.join(',') , 'serviceextinfo', service['service_description']
+
+ print_block files['serviceextinfo'], 'serviceextinfo', service['_extinfo'], %w()
+end
+
+# hostlists in services can be given as both, single hosts and hostgroups
+# This functinn merges hostgroups and a simple list of hosts
+#
+# it also takes a prefix so that it can be used for excludelists as well
+def merge_hosts_and_hostgroups(service, servers, hostgroups, prefix)
+ hosts = []
+ hosts = service[prefix+'hosts'].split(/,/).map{ |x| x.strip } if service[prefix+'hosts']
+ hosts.each{ |host|
+ throw "host #{host} does not exist - used in service #{service['service_description']}" unless servers[host]
+ };
+ if service[prefix+'hostgroups']
+ service[prefix+'hostgroups'].split(/,/).map{ |x| x.strip }.each{ |hg|
+ throw "hostgroup #{hg} does not exist - used in service #{service['service_description']}" unless hostgroups[hg]
+ hosts = hosts.concat hostgroups[hg]['_memberlist']
+ }
+ end
+
+ return hosts
+end
+
+# Figure out the hosts a given service applies to
+#
+# For a given service find the list of hosts minus excluded hosts that this service runs on
+def find_hosts(service, servers, hostgroups)
+ hosts = merge_hosts_and_hostgroups service, servers, hostgroups, ''
+ excludehosts = merge_hosts_and_hostgroups service, servers, hostgroups, 'exclude'
+
+ excludehosts.each{ |host|
+ if hosts.delete(host) == nil
+ throw "Cannot remove host #{host} from service #{service['service_description']}: it's not included anyway or excluded twice."
+ end
+ }
+
+ return hosts
+end
+
+# Move all elements that have a key that starts with "extinfo-"
+# into the _extinfo subhash
+def split_away_extinfo(hash)
+ hash['_extinfo'] = {}
+ hash.keys.each{ |key|
+ if key[0, 8] == 'extinfo-'
+ hash['_extinfo'][ key[8, key.length-8] ] = hash[key]
+ hash.delete(key);
+ end
+ }
+end
+
+
+#############################################################################################
+#############################################################################################
+#############################################################################################
+
+# Load the config
+config = YAML::load( File.open( 'nagios-master.cfg' ) )
+
+files = {}
+# Remove old created files
+nagios_filename.each_pair{ |name, filename|
+ files[name] = File.new(filename, "w")
+}
+
+#################################
+# create a few hostgroups
+#################################
+# create the "all" and "pingable" hostgroups
+config['hostgroups']['all'] = {}
+config['hostgroups']['all']['alias'] = "all servers"
+config['hostgroups']['pingable'] = {}
+config['hostgroups']['pingable']['alias'] = "pingable servers"
+
+config['hostgroups'].each_pair{ |name, hg|
+ throw "Empty hostgroup or hostgroup #{name} not a hash" unless hg.kind_of?(Hash)
+ split_away_extinfo hg
+
+ hg['_memberlist'] = []
+}
+
+config['servers'].each_pair{ |name, server|
+ throw "Empty server or server #{name} not a hash" unless server.kind_of?(Hash)
+
+ split_away_extinfo server
+
+ throw "No hostgroups defined for #{name}" unless server['hostgroups']
+ server['_hostgroups'] = server['hostgroups'].split(/,/).map{ |x| x.strip };
+ server['_hostgroups'] << 'all'
+ server['_hostgroups'] << 'pingable' unless server['pingable'] == false
+
+ server['_hostgroups'].each{ |hg|
+ throw "Hostgroup #{hg} is not defined" unless config['hostgroups'].has_key?(hg)
+ config['hostgroups'][hg]['_memberlist'] << name
+ };
+}
+
+##############
+# HOSTS
+##############
+config['servers'].each_pair{ |name, server|
+ # Formerly we used 'ip' instead of 'address' in our source file
+ # Handle this change but warn XXX
+ if server.has_key?('ip')
+ STDERR.puts("Host definition for #{name} has an 'ip' field. Please use 'address' instead");
+ server['address'] = server['ip'];
+ server.delete('ip');
+ end
+
+ set_complain_if_set server, 'host_name' , name, 'Host', name
+ set_if_unset server, 'alias' , name
+ set_if_unset server, 'use' , HOST_TEMPLATE_NAME
+ set_if_unset server, 'check_command', HOST_ALIVE_CHECK unless server['pingable'] == false
+
+ print_block files['hosts'] , 'host' , server , %w(hostgroups pingable)
+
+
+
+ # Handle hostextinfo
+ config['hostgroups'][ server['_hostgroups'].first ]['_extinfo'].each_pair{ |k, v|
+ # substitute hostname into the notes_url
+ v = sprintf(v,name) if k == 'notes_url'
+
+ set_if_unset server['_extinfo'], k ,v
+ }
+
+ set_complain_if_set server['_extinfo'], 'host_name' , name, 'hostextinfo', name
+ set_if_unset server['_extinfo'], 'vrml_image' , server['_extinfo']['icon_image'] if server['_extinfo'].has_key?('icon_image')
+ set_if_unset server['_extinfo'], 'statusmap_image' , server['_extinfo']['icon_image'] if server['_extinfo'].has_key?('icon_image')
+
+ print_block files['hostextinfo'], 'hostextinfo', server['_extinfo'], %w()
+}
+
+
+
+##############
+# HOSTGROUPS
+##############
+config['hostgroups'].each_pair{ |name, hg|
+ next if hg['private']
+
+ set_complain_if_set hg, 'hostgroup_name', name , 'Hostgroup', name
+ set_complain_if_set hg, 'members' , hg['_memberlist'].join(","), 'Hostgroup', name
+ set_if_unset hg, 'contact_groups', CONTACTGROUP
+
+ print_block files['hostgroups'], 'hostgroup', hg, %w()
+}
+
+
+##############
+# SERVICES and DEPENDENCIES
+##############
+config['services'].each{ |service|
+ throw "Empty service or service not a hash" unless service.kind_of?(Hash)
+
+ split_away_extinfo service
+
+
+ # Both 'name' and 'service_description' are valid for a service's name
+ # Internally we only use service_description as that's nagios' official term
+ if service.has_key?('name')
+ throw "Service definition has both a name (#{service['name']})" +
+ "and a service_description (#{service['service_description']})" if service.has_key?('service_description')
+ #STDERR.puts("Service definition #{service['name']} has a 'name' field. Please use 'service_description' instead");
+ service['service_description'] = service['name'];
+ service.delete('name');
+ end
+ # Both 'check' and 'check_command' are valid for a service's check command
+ # Internally we only use check_command as that's nagios' official term
+ if service.has_key?('check')
+ throw "Service definition has both a check (#{service['check']})" +
+ "and a check_command (#{service['check_command']})" if service.has_key?('check_command')
+ #STDERR.puts("Service definition #{service['service_description']} has a 'check' field. Please use 'check_command' instead");
+ service['check_command'] = service['check'];
+ service.delete('check');
+ end
+
+
+ hosts = find_hosts service, config['servers'], config['hostgroups']
+ throw "no hosts for service #{service['service_description']}" if hosts.empty?
+
+ throw "nrpe, check, and remotecheck are mutually exclusive in service #{service['service_description']}" if
+ (service['nrpe'] ? 1 : 0) +
+ (service['check_command'] ? 1 : 0) +
+ (service['remotecheck'] ? 1 : 0) >= 2
+
+ if service['runfrom'] && service['remotecheck']
+ # If the service check is to be run from a remote monitor server ("relay")
+ # add that as an NRPE check to be run on the relay and make this
+ # service also depend on NRPE on the relay
+ relay = service['runfrom']
+
+ hosts.each{ |host|
+ # how to recursively copy this thing?
+ hostservice = YAML::load( service.to_yaml )
+ host_ip = config['servers'][host]['address']
+ throw "For some reason I do not have an address for #{host}. This shouldn't be." unless host_ip
+
+ check = $nrpe.add("#{host}_#{hostservice['service_description']}", hostservice['remotecheck'].gsub(/\$HOSTADDRESS\$/, host_ip))
+ hostservice['check_command'] = "#{NRPE_CHECKNAME_HOST}!#{ config['servers'][ relay ]['address'] }!#{ check }"
+
+ # Make sure dependencies are an array. If there are none, create an empty array
+ # if depends is just a string, make a list with just that element
+ hostservice['depends'] = ensure_array( hostservice['depends'] )
+ # And append this new dependency
+ hostservice['depends'] << "#{ relay }:#{ NRPE_PROCESS_SERVICE }";
+
+ addService( [ host ], hostservice, files)
+ }
+ elsif service['runfrom'] || service['remotecheck']
+ throw "runfrom and remotecheck must either appear both or not at all in service #{service['service_description']}"
+ throw "must not remotecheck without runfrom" if service['remotecheck']
+ else
+ addService(hosts, service, files)
+ end
+}
+
+
+##############
+# NRPE config file
+##############
+$nrpe.checks.each_pair{ |name, check|
+ files['nrpe'].puts "command[#{ name }]=#{ check }"
+}
+
+