fix missing ipaddr require

[colinsurprenant]

The IPAddr class is used but the ipaddr library is never required. If no other plugins does a require "ipaddr" then the udp input will crash on startup with:

[WARN ][logstash.inputs.udp ] UDP listener died {:exception=>#<NameError: uninitialized constant LogStash::Inputs::Udp::IPAddr>, :backtrace=>["org/jruby/RubyModule.java:2746:in const_missing'", "/usr/share/logstash/vendor/bundle/jruby/1.9/gems/logstash-input-udp-3.3.1/lib/logstash/inputs/udp.rb:87:inudp_listener'", "/usr/share/logstash/vendor/bundle/jruby/1.9/gems/logstash-input-udp-3.3.1/lib/logstash/inputs/udp.rb:57:in run'", "/usr/share/logstash/logstash-core/lib/logstash/pipeline.rb:470:ininputworker'", "/usr/share/logstash/logstash-core/lib/logstash/pipeline.rb:463:in `start_input'"]}

This fix is simply to require that library.

[jsvd]

I suggest removing any other require of ipaddr like https://github.com/logstash-plugins/logstash-input-udp/blob/master/spec/support/client.rb#L3

[colinsurprenant]

meh - if you insist I canl do it but OTOH it's totally ok to require a lib that is used in the file. For example, if udp.rb stops using it but it's still in use in client.rb then it won't break. In fact I'd argue that this is preferable actually.

[colinsurprenant]

actually ... doing that risks reproducing the exact same problem we are solving here :P

[jsvd]

I guess my argument comes from ipaddr now being a runtime dependency in the gemspec so it must be required in the "lib/" files not the "spec"

That said I'm not blocking this PR b/c of this, up to you.
LGTM

[colinsurprenant]

« ipaddr now being a runtime dependency in the gemspec so it must be required in the "lib/" files not the "spec"» not following what you mean!?

[jsvd]

ipaddr now being a runtime dependency in the gemspec

I forgot ipaddr is stdlib, but my argument was that any runtime dependency should be included in the lib/logstash/inputs/udp.rb, which means we'd never need to include in the specs.

I'm still LGTM on this.

[colinsurprenant]

I personally think that not having an explicit require "somelib" in a file that explicitly uses Someclass is an anti-pattern. In this case the IPAddr class in client.rb is used independently for its usage in udp.rb and if one day IPAddr is not used anymore in udp.rb for whatever reason, that does not mean that IPAddr will not be used in client.rb and following your suggestion of removing require "ipaddr" from client.rb it would result in a bug when running specs.

[jsvd]

Makes sense, agreed.

[jsvd]

I guess my argument comes from ipaddr now being a runtime dependency in the gemspec so it must be required in the "lib/" files not the "spec"

That said I'm not blocking this PR b/c of this, up to you.
LGTM

[colinsurprenant]

merged and published as v3.3.2.