compare host using lowercase

[shantanugadgil]

use lowercase comparison for host lookup #542

[CLAassistant]

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[aaronhurt]

Moving conversation from #542 over here. Looking a bit deeper into the code it seems a bit inconsistent. When adding a route via a service tag the host is always forced lowercase as you have observed via parseURLPrefixTag (https://github.com/fabiolb/fabio/blob/master/registry/consul/parse.go#L48)

Furthermore, incoming hosts are not always forced lower-case before searching the table. To be consistent we may want to modify the underlying addRoute (https://github.com/fabiolb/fabio/blob/master/route/table.go#L137) function to also force lowercase the host in addition to forcing a lowercase lookup.

[shantanugadgil]

@leprechau my Go skills are pretty basic and I had suggested this change as it worked for me.
(I have tested the binary for my use case)

I am perfectly fine with any other changes as well.
Should I resubmit with the other changes?

[aaronhurt]

I think we can make all lookups and adds lowercase by making two simple changes in route/table.go like this ...

diff --git a/route/table.go b/route/table.go
index bb689dc..1646e74 100644
--- a/route/table.go
+++ b/route/table.go
@@ -136,6 +136,7 @@ func NewTable(s string) (t Table, err error) {
 // addRoute adds a new route prefix -> target for the given service.
 func (t Table) addRoute(d *RouteDef) error {
        host, path := hostpath(d.Src)
+       host = strings.ToLower(host) // maintain compatibility with parseURLPrefixTag
 
        if d.Src == "" {
                return errInvalidPrefix
@@ -383,6 +384,7 @@ func (t Table) LookupHost(host string, pick picker) *Target {
 }
 
 func (t Table) lookup(host, path, trace string, pick picker, match matcher) *Target {
+       host = strings.ToLower(host) // routes are always added lowercase
        for _, r := range t[host] {
                if match(path, r) {
                        n := len(r.Targets)

This wouldn't require any changes to the lookupHostFn in main.go as that function calls Lookup which in turn calls the lookup function in table.go

[aaronhurt]

Running a make test those two changes to table.go don't appear to break existing tests.

[aaronhurt]

@shantanugadgil Thank you!

[shantanugadgil]

hehe @leprechau thank you !!! 👍