Editing INI style files with puppetlabs-inifile

INI files are used throughout many systems, Puppet uses INI syntax for the puppet.conf file. The puppetlabs-inifile module creates two types, ini_setting and ini_subsetting, which can be used to edit INI style files.

Getting ready

Install the module from the forge as follows:

t@mylaptop ~ $ puppet module install puppetlabs-inifile
Notice: Preparing to install into /home/tuphill/.puppet/modules ...
Notice: Downloading from https://forgeapi.puppetlabs.com ...
Notice: Installing -- do not interrupt ...
/home/tuphill/.puppet/modules
└── puppetlabs-inifile (v1.1.3)

How to do it...

In this example, we will create a /tmp/server.conf file and ensure that the server_true setting is set in that file:

1. Create an initest.pp manifest with the following contents:

     ini_setting {'server_true':
       path    => '/tmp/server.conf',
       section => 'main',
       setting => 'server',
       value   => 'true',
     }

2. Apply the manifest:

   t@mylaptop ~/.puppet/manifests $ puppet apply initest.pp 
   Notice: Compiled catalog for burnaby in environment production in 0.14 seconds
   Notice: /Stage[main]/Main/Ini_setting[server_true]/ensure: created
   Notice: Finished catalog run in 0.02 seconds
   

3. Verify the contents of the /tmp/server.conf file:

   t@mylaptop ~/.puppet/manifests $ cat /tmp/server.conf 
   
   [main]
   server = true
   

How it works...

The inifile module defines two types, ini_setting and ini_subsetting. Our manifest defines an ini_setting resource that creates a server = true setting within the main section of the ini file. In our case, the file didn't exist, so Puppet created the file, then created the main section, and finally added the setting to the main section.

There's more...

Using ini_subsetting, you can have several resources added to a setting. For instance, our server.conf file has a server's line, we could have each node append its own hostname to a server's line. Add the following to the end of the initest.pp file:

  ini_subsetting {'server_name':
    path    => '/tmp/server.conf',
    section => 'main',
    setting => 'server_host',
    subsetting => "$hostname",
  }

Apply the manifest:

t@mylaptop ~/.puppet/manifests $ puppet apply initest.pp 
Notice: Compiled catalog for mylaptop in environment production in 0.34 seconds
Notice: /Stage[main]/Main/Ini_subsetting[server_name]/ensure: created
Notice: Finished catalog run in 0.02 seconds
t@mylaptop ~/.puppet/manifests $ cat /tmp/server.conf 
[main]
server = true
server_host = mylaptop

Now temporarily change your hostname and rerun Puppet:

t@mylaptop ~/.puppet/manifests $ sudo hostname inihost
t@mylaptop ~/.puppet/manifests $ puppet apply initest.pp 
Notice: Compiled catalog for inihost in environment production in 0.43 seconds
Notice: /Stage[main]/Main/Ini_subsetting[server_name]/ensure: created
Notice: Finished catalog run in 0.02 seconds
t@mylaptop ~/.puppet/manifests $ cat /tmp/server.conf 
[main]
server = true
server_host = mylaptop inihost

Tip

When working with INI syntax files, using the inifile module is an excellent choice.

If your configuration files are not in INI syntax, another tool, Augeas, can be used. In the following section, we will use augeas to modify files.