####Table of Contents

1. Overview
2. Setup - The basics of getting started with extlib
3. Usage - Configuration options and additional functionality
4. Limitations - OS compatibility, etc.
5. Development - Guide for contributing to the module

##Overview

This module provides functions that are out of scope for stdlib. Some of them are even intristically tied to stdlib.

##Setup

 % puppet module install puppet-extlib

##Usage

###resources_deep_merge

• Type: rvalue

Returns a deep-merged resource hash (hash of hashes).

Examples:

    $tcresource_defaults = {
      ensure     => 'present',
      attributes => {
        driverClassName => 'org.postgresql.Driver',
      }
    }

    $tcresources = {
      'app1:jdbc/db1' => {
        attributes => {
          url      => 'jdbc:postgresql://localhost:5432/db1',
          userpass => 'user1:pass1',
        },
      },
      'app2:jdbc/db2' => {
        attributes => {
          url      => 'jdbc:postgresql://localhost:5432/db2',
          userpass => 'user2:pass2',
        },
      }
    }

When called as:

    $result = resources_deep_merge($tcresources, $tcresource_defaults)

will return:

    {
     'app1:jdbc/db1' => {
       ensure     => 'present',
       attributes => {
         url      => 'jdbc:postgresql://localhost:5432/db1',
         userpass => 'user1:pass1',
         driverClassName => 'org.postgresql.Driver',
       },
     },
     'app2:jdbc/db2' => {
       ensure     => 'present',
       attributes => {
         url      => 'jdbc:postgresql://localhost:5432/db2',
         userpass => 'user2:pass2',
         driverClassName => 'org.postgresql.Driver',
       },
     }
    }

###echo

This function outputs the variable content and its type to the debug log. It's similiar to the "notice" function but provides a better output format useful to trace variable types and values in the manifests.

# examples:
$v1 = 'test'
$v2 = ["1", "2", "3"]
$v3 = {"a"=>"1", "b"=>"2"}
$v4 = true
# $v5 is not defined
$v6 = { "b" => ["1","2","3"] }
$v7 = 12345

echo($v1, 'My string')
echo($v2, 'My array')
echo($v3, 'My hash')
echo($v4, 'My boolean')
echo($v5, 'My undef')
echo($v6, 'My structure')
echo($v7) # no comment here

# debug log output:
# My string (String) "test"
# My array (Array) ["1", "2", "3"]
# My hash (Hash) {"a"=>"1", "b"=>"2"}
# My boolean (TrueClass) true
# My undef (String) ""
# My structure (Hash) {"b"=>["1", "2", "3"]}
# (String) "12345"

###cache_data

Retrieves data from a cache file, or creates it with supplied data if the file doesn't exist. Useful for having data that's randomly generated once on the master side (e.g. a password), but then stays the same on subsequent runs. The cache_data takes three parameters:

• namespace: the folder under Puppet's vardir that the data is placed (e.g. mysql becomes /var/lib/puppet/mysql)
• data_name: the filename to store the data as (e.g. mysql_password becomes /var/lib/puppet/mysql/mysql_password)
• initial_data: the data to store and cache in the data_name file

Examples:

class mymodule::params {

  $password = cache_data('mysql', 'mysql_password', 'this_is_my_password')

}

###random_password

Returns a string of arbitrary length that contains randomly selected characters.

Examples:

Prototype:

    random_password(n)

Where n is a non-negative numeric value that denotes length of the desired password.

Given the following statements:

  $a = 4
  $b = 8
  $c = 16

  notice random_password($a)
  notice random_password($b)
  notice random_password($c)

The result will be as follows:

  notice: Scope(Class[main]): fNDC
  notice: Scope(Class[main]): KcKDLrjR
  notice: Scope(Class[main]): FtvfvkS9j9wXLsd6

##Limitations

This module requires puppetlabs-stdlib >=3.2.1, which is when deep_merge() was introduced.

##Development

We highly welcome new contributions to this module, especially those that include documentation, and rspec tests ;) but will happily guide you through the process, so, yes, please submit that pull request!

This module uses blacksmith for releasing and rspec for tests.

To release a new version please make sure tests pass! Then,

% rake travis_release

This will tag the current state under the version number described in metadata.json, and then bump the version there so we're ready for the next iteration. Finally it will git push --tags so travis can pick it up and release it to the forge!