Respect sort-backends flag

[gjtempleton]

Resolves the issue discussed in #240

• Adds a new field to HAProxyBackendSlots struct called FullSlotIndices of type []string - this is used purely to track the order of processing of endpoint targets

• Appends new targets to FullSlotIndices as each upstream is processed and added to the backend

• Updates the template to range over FullSlotIndices for each backend rather than range $target, $slot := $BackendSlots.FullSlots as this causes the map to become ordered alphabetically

• Tested in a local fork and build with both the default behaviour of sort-backends=false and explicitly setting sort-backends=true

• Existing configs should continue to work as before as no changes made to the structure of existing data structures used in the template

[jcmoraisjr]

Hi, sorry about the delay and thanks for supporting this ingress controller!

The current implementation isn't working with dynamic updates - servers aren't being added to the backend farm. There are other places on dynconfig that FullSlots was updated but FullSlotIndices wasn't.

Besides that I'd also suggest you to convert the FullSlots itself from a map to a slice instead of using another slice (FullSlotIndices) to save the correct order.

[gjtempleton]

Hi, no worries, and thanks for the feedback.

That's my bad, I didn't test it with dynamic backends as we don't make use of that internally, I'll grab some time today to have another look.

Thanks again for the feedback!

[jcmoraisjr]

I've just merged #247 which "unsort" backend in a backward compatible way. I'll shortly notify in #240 as soon as a new tag is pushed and a new image is built. Closing. Please update the issue if you have any problem.