External check pleases me greatly, but sending emails for me seems to be overkill, there are well established ways to do this in unified manner (logparsers, snmp traps etc).
Half way trough to fullfill Zawinski's Law.
I guess part of my concern with Lua was the example on the linked article. It seems to be able to interface with most of the system and not just as a content source, which makes more sense.
> Since 1.6, HAProxy can forge SSL certificate on the fly! Yes, you can use HAProxy with your company’s CA to inspect content.
> Device Identification
(Considering it seems you need a proprietary lib)
> mailers
> lua
> Processing of HTTP request body
All seem to be be moving away from what HAProxy is/was. It's not an application server. It's not a webserver. It's not a mail server.