Puppet Asp.net web.config - web-config

Question

We are looking for using hierra data configuration for Application configuration management. Asp.net uses Web.config and App.config files which have the configuration values as key , value pairs
Example:
<appSettings>
<add key="key1" value="Web"/>
<add key="key2" value="16.2"/>
</appSettings>
Currently we are using EPP templates with place holders for the values and generate the file on the fly.
<add key="key1" value="<%= $class_name::value1%>"/>
Just wanted to check whats the best practice for managing configuration files like web.config, app.config using Puppet. Suggestions are welcome.

Answer 1

Templates
The recommendation is nearly always templates when you can control the entire file. There is fairly comprehensive documentation on templating.
Use EPP for Puppet 4.x+.
Use ERB for Puppet 3.x+.
XML Fragments
If you cannot or do not want to control the whole file, another alternative is xml_fragment available on the forge (https://forge.puppet.com/ianoberst/xml_fragment).
You can see that it's a bit more verbose than templating, but has granularity for purging and ensuring elements for a file.
xml_fragment { "appsetting key1":
path => "C:/sites/site/web.config",
ensure => 'present',
xpath => "/configuration/appSettings/add[#key='key1']",
content => {
attributes {
"value" => "web"
}
}
}
xml_fragment { "appsetting key2":
path => "C:/sites/site/web.config",
ensure => 'present',
xpath => "/configuration/appSettings/add[#key='key2']",
content => {
attributes {
"value" => "16.2"
}
}
}