Parameterize Logstash home directory

[joshuaspence]

Define $logstash::home_dir = '/usr/share/logstash' to avoid needless repetition.

[ninaspitfire]

This is really just declaring a constant rather than a parameter, isn't it?

The same amount of repetition is present, but it's slightly harder to read, because now the reader has to do a "variable lookup" in their head.

[ahharu]

I would rather have it added as a parameter on the "logstash" class at init.pp so we can install it wherever we want

[joshuaspence]

@jarpy, correct. But defining it as a constant means that it can then be used externally. For example, we have Puppet install development dependencies with /use/share/Logstash/bin/logstash-plugin install --development (see #292) and would prefer not to have to hardcode the path here.

[joshuaspence]

@ahharu, this setting doesn't actually change where Logstash is installed because it is installed from a package, so it would be misleading to allow this path to be configurable.

[joshuaspence]

This change would also make it easier for the Puppet module to support the installation of Puppet on Windows, if we care about that.

[ninaspitfire]

defining it as a constant means that it can then be used externally

Good point, thanks for helping me get it.

I think I instinctively ignored that possibility, because it feels "wrong" to reference variables across domains like that. That's a feeling about programming in general though. Obviously, in Puppet, this is a pretty normal and common thing to do.