Puppet users - Jun 2007 - lookup in CSV recipe

I await Luke''s node settings implementation with interest.  At the
moment however, I have this sort of ugliness:

 $site = $hostname ? {
    fred => "opsera",
    barney => "bedrock",
    default => "unknown site",
    ...
 }
		       
So I''ve knocked up this little function to use CSV files instead.  Now
I can just do:

$site = lookup_csv("sites.csv",$hostname,"site")

where sites.csv is:
hostname,site,ip
fred,opsera,192.168.1.1
barney,bedrock,10.0.0.1

This is much nicer IMO - in particular I only need to change a .csv
file.  That file is likely to be exported from a spreadsheet which
makes life even easier (later versions could just read the spreadsheet).

Beware: this is _definitely_ v0.1 - I''ve only done a couple of days of
Ruby so it''s more proof of concept than a final version - it''s
also
only been tested for 5mins.  Even so I thought it might be useful.

I thought about adding it to the wiki, but thought I should check here
first.


# lookup items from a CSV file

# v0.1 - 2007/06/06
# Adrian Bridgett, Opsera Ltd.

# file in the format of:
# colname1, colname2, colname3,...  (must be first line)
# key1, value2, value3,...
# key2, value4, value5
#
# lookup_csv(filename,key1,colname3) will then return value3
#
# TODO:
# proper CSV parsing (e.g. quoting)
# regexp on the value?
# return a supplied default if row not found?
# add Excel and Openoffice support

module Puppet::Parser::Functions
  newfunction(:lookup_csv, :type => :rvalue) do |args|
    filename = args[0]
    key = args[1]
    column = args[2]
    File.open(filename) do |file|
      # find which column we are after 
      colnum = file.gets.chomp.split(/,/).index(column)
      return nil if colnum == nil
      # find row
      file.each_line { |line| 
        row = line.chomp.split(/,/)
        if (row[0] == key)
          return row[colnum]
        end
      }
    end
    # no match found
    return nil
  end
end


Adrian

On Wed, Jun  6, 2007 at 10:02:05 +0100 (+0100),  wrote:
> Beware: this is _definitely_ v0.1 - I''ve only done a couple of
days of
> Ruby so it''s more proof of concept than a final version -
it''s also
> only been tested for 5mins.  Even so I thought it might be useful.
And obviously not very well.  v0.2 actually works (no guarantee, the
quality of coding can go down as well as up, yada yada) ...

# lookup items from a CSV file

# v0.2 - 2007/06/06
# Adrian Bridgett, Opsera Ltd.

# file in the format of:
# colname1, colname2, colname3,...  (must be first line)
# key1, value2, value3,...
# key2, value4, value5
#
# lookup_csv(filename,key1,colname3) will then return value3
#
# TODO:
# proper CSV parsing (e.g. quoting)
# regexp on the value?
# return a supplied default if row not found?
# add Excel and Openoffice support

module Puppet::Parser::Functions
  newfunction(:lookup_csv, :type => :rvalue) do |args|
    filename = args[0]
    key = args[1]
    column = args[2]
    rc = nil
    File.open(filename) do |file|
      # find which column we are after 
      colnum = file.gets.chomp.split(/,/).index(column)
      break if colnum == nil
      # find row
      file.each_line { |line| 
        row = line.chomp.split(/,/)
        if (row[0] == key)
          rc = row[colnum]
          break
        end
      }
    end
    return rc
  end
end


Adrian

v0.3 (probably last one for a little while)

This uses FasterCSV to do parsing and supports arrays in the CSV when
they are specified like this: "[foo,bar]".

# lookup items from a CSV file

# v0.3 - 2007/06/06
# Adrian Bridgett, Opsera Ltd.

# file in the format of:
# colname1, colname2, colname3,...  (must be first line)
# key1, value2, value3,...
# key2, value4, value5
#
# lookup_csv(filename,key1,colname3) will then return value3
#
# TODO:
# regexp on the key?
# return a supplied default if row not found?
# add Excel and Openoffice support

# Changelog
# v0.3 - use FasterCSV, arrays supported
# v0.2 - bugfixed (return in middle of loop)
# v0.1 - initial version

require "faster_csv"

module Puppet::Parser::Functions
  newfunction(:lookup_csv, :type => :rvalue) do |args|
    filename = args[0]
    key = args[1]
    column = args[2]
    rc = nil
    FasterCSV::open(filename) do |csv_file|
      # find which column we are after 
      colnum = csv_file.readline.index(column)
      break if colnum == nil
      # find matching line
      csv_file.each { |line| 
        if (line[0] == key)
          rc = line[colnum]
          if (rc =~ /^\[(.*)\]$/)
            rc = $1.split(/,/)
          end
          break
        end
      }
    end
    return rc
  end
end


Adrian