# common/manifests/defines/line.pp -- a trivial mechanism to ensure a line exists in a file
# Copyright (C) 2007 David Schmitt <david@schmitt.edv-bus.at>
# See LICENSE for the full license granted to you.

# Ensures that a specific line is present or absent in a file. This can
# be very brittle, since even small changes can throw this off.
#
# If the line is not present yet, it will be appended to the file.
# 
# The name of the define is not used. Just keep it (globally) unique and
# descriptive.
#
# Use this only for very trivial stuff. Usually replacing the whole file
# is a more stable solution with less maintenance headaches afterwards.
#
# Usage:
# line {
#   description:
#     file => "filename",
#     line => "content",
#     ensure => {absent,*present*}
# }
#
# Example:
# The following ensures that the line "allow ^$munin_host$" exists in
# /etc/munin/munin-node.conf, and if there are any changes notify the
# service for a restart
#
#  line {
#  	allow_munin_host:
#  		file => "/etc/munin/munin-node.conf",
#  		line => "allow ^$munin_host$",
#  		ensure => present,
#  		notify => Service[munin-node],
#  		require => Package[munin-node];
#  }
#
# Code with fixes gathered at
# http://reductivelabs.com/trac/puppet/wiki/Recipes/SimpleText
define line($file, $line, $ensure = 'present') {
  case $ensure {
    default: { err ( "unknown ensure value ${ensure}" ) }
    present: {
      exec { "/bin/echo '${line}' >> '${file}'":
        unless  => "/bin/grep -qFx '${line}' '${file}'",
        require => File["${file}"],
      }
    }
    absent: {
      exec { "/usr/bin/perl -ni -e 'print unless /^\\Q${line}\\E\$/' '${file}'":
        onlyif => "/bin/grep -qFx '${line}' '${file}'",
      }
    }
    uncomment: {
      exec { "/bin/sed -i -e'/${line}/s/^#\+//' '${file}'":
        onlyif => "/bin/grep '${line}' '${file}' | /bin/grep '^#' | /usr/bin/wc -l"
      }
    }
    comment: {
      exec { "/bin/sed -i -e'/${line}/s/^\(.\+\)$/#\1/' '${file}'":
        onlyif  => "/usr/bin/test `/bin/grep '${line}' '${file}' | /bin/grep -v '^#' | /usr/bin/wc -l` -ne 0",
        require => File["${file}"],
      }
    }
  }
}