From ea34ee6ce64436b41ddb5a9bf71ef311fdf8b92b Mon Sep 17 00:00:00 2001 From: James Turnbull Date: Mon, 3 Aug 2009 23:12:13 +1000 Subject: Added R.I.Pienaar's extlookup.rb to the ext directory --- ext/extlookup.rb | 183 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 183 insertions(+) create mode 100644 ext/extlookup.rb (limited to 'ext') diff --git a/ext/extlookup.rb b/ext/extlookup.rb new file mode 100644 index 000000000..b0978ef12 --- /dev/null +++ b/ext/extlookup.rb @@ -0,0 +1,183 @@ +# Puppet External Data Sources +# +# This is a parser function to read data from external files, this version +# uses CSV files but the concept can easily be adjust for databases, yaml +# or any other queryable data source. +# +# The object of this is to make it obvious when it's being used, rather than +# magically loading data in when an module is loaded I prefer to look at the code +# and see statements like: +# +# $snmp_contact = extlookup("snmp_contact") +# +# The above snippet will load the snmp_contact value from CSV files, this in its +# own is useful but a common construct in puppet manifests is something like this: +# +# case $domain { +# "myclient.com": { $snmp_contact = "John Doe " } +# default: { $snmp_contact = "My Support " } +# } +# +# Over time there will be a lot of this kind of thing spread all over your manifests +# and adding an additional client involves grepping through manifests to find all the +# places where you have constructs like this. +# +# This is a data problem and shouldn't be handled in code, a using this function you +# can do just that. +# +# First you configure it in site.pp: +# $extlookup_datadir = "/etc/puppet/manifests/extdata" +# $extlookup_precedence = ["%{fqdn}", "domain_%{domain}", "common"] +# +# The array tells the code how to resolve values, first it will try to find it in +# web1.myclient.com.csv then in domain_myclient.com.csv and finally in common.csv +# +# Now create the following data files in /etc/puppet/manifests/extdata +# +# domain_myclient.com.csv: +# snmp_contact,John Doe +# root_contact,support@%{domain} +# client_trusted_ips,192.168.1.130,192.168.10.0/24 +# +# common.csv: +# snmp_contact,My Support +# root_contact,support@my.com +# +# Now you can replace the case statement with the simple single line to achieve +# the exact same outcome: +# +# $snmp_contact = extlookup("snmp_contact") +# +# The obove code shows some other features, you can use any fact or variable that +# is in scope by simply using %{varname} in your data files, you can return arrays +# by just having multiple values in the csv after the initial variable name. +# +# In the event that a variable is nowhere to be found a critical error will be raised +# that will prevent your manifest from compiling, this is to avoid accidentally putting +# in empty values etc. You can however specify a default value: +# +# $ntp_servers = extlookup("ntp_servers", "1.${country}.pool.ntp.org") +# +# In this case it will default to "1.${country}.pool.ntp.org" if nothing is defined in +# any data file. +# +# You can also specify an additional data file to search first before any others at use +# time, for example: +# +# $version = extlookup("rsyslog_version", "present", "packages") +# +# package{"rsyslog": ensure => $version } +# +# This will look for a version configured in packages.csv and then in the rest as configured +# by $extlookup_precedence if it's not found anywhere it will default to "present", this kind +# of use case makes puppet a lot nicer for managing large amounts of packages since you do not +# need to edit a load of manifests to do simple things like adjust a desired version number. +# +# For more information on installing and writing your own custom functions see: +# http://reductivelabs.com/trac/puppet/wiki/WritingYourOwnFunctions +# +# For further help contact Volcane on #puppet +require 'csv' + +module Puppet::Parser::Functions + newfunction(:extlookup, :type => :rvalue) do |args| + key = args[0] + default = "_ExtUNSET_" + datafile = "_ExtUNSET_" + + default = args[1] if args[1] + datafile = args[2] if args[2] + + extlookup_datadir = lookupvar('extlookup_datadir') + extlookup_precedence = Array.new + + # precedence values can have variables embedded in them + # in the form %{fqdn}, you could for example do + # + # $extlookup_precedence = ["hosts/%{fqdn}", "common"] + # + # this will result in /path/to/extdata/hosts/your.box.com.csv + # being searched. + # + # we parse the precedence here because the best place to specify + # it would be in site.pp but site.pp is only evaluated at startup + # so $fqdn etc would have no meaning there, this way it gets evaluated + # each run and has access to the right variables for that run + lookupvar('extlookup_precedence').each do |prec| + while prec =~ /%\{(.+?)\}/ + prec.gsub!(/%\{#{$1}\}/, lookupvar($1)) + end + + extlookup_precedence << prec + end + + + datafiles = Array.new + + # if we got a custom data file, put it first in the array of search files + if datafile != "" + if File.exists?(extlookup_datadir + "/#{datafile}.csv") + datafiles << extlookup_datadir + "/#{datafile}.csv" + end + end + + extlookup_precedence.each do |d| + datafiles << extlookup_datadir + "/#{d}.csv" + end + + desired = "_ExtUNSET_" + + datafiles.each do |file| + parser.watch_file(file) if File.exists?(file) + + if desired == "_ExtUNSET_" + if File.exists?(file) + result = CSV.read(file).find_all do |r| + r[0] == key + end + + + # return just the single result if theres just one, + # else take all the fields in the csv and build an array + if result.length > 0 + if result[0].length == 2 + val = result[0][1].to_s + + # parse %{}'s in the CSV into local variables using lookupvar() + while val =~ /%\{(.+?)\}/ + val.gsub!(/%\{#{$1}\}/, lookupvar($1)) + end + + desired = val + elsif result[0].length > 1 + length = result[0].length + cells = result[0][1,length] + + # Individual cells in a CSV result are a weird data type and throws + # puppets yaml parsing, so just map it all to plain old strings + desired = cells.map do |c| + # parse %{}'s in the CSV into local variables using lookupvar() + while c =~ /%\{(.+?)\}/ + c.gsub!(/%\{#{$1}\}/, lookupvar($1)) + end + + c.to_s + end + end + end + end + end + end + + # don't accidently return nil's and such rather throw a parse error + if desired == "_ExtUNSET_" && default == "_ExtUNSET_" + raise Puppet::ParseError, "No match found for '#{key}' in any data file during extlookup()" + else + desired = default if desired == "_ExtUNSET_" + end + + desired + end +end + +# vi:tabstop=4:expandtab:ai -- cgit