Add new & improved glob matcher

[sharbov]

I've added a new matcher using gobwas/glob side-by-side to the existing glob matcher

This might hinder performance due to the fact that the matcher is compiling the pattern each time.

I was thinking of using a cache for the compiled matchers (something like patrickmn/go-cache).

@magiconair what do you think?

#452

[CLAassistant]

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[magiconair]

You can cache the compiled pattern in the Route object and update the addRoute method in the Table

https://github.com/fabiolb/fabio/blob/master/route/table.go#L137-L173

Also, If this glob library is backwards-compatible with https://github.com/ryanuber/go-glob then I would suggest to just replace it instead of adding another one. Can you check?

[sharbov]

Hey @magiconair,

I've implemented the fixes you've requested.
As far as I can tell the two glob packages are compatible,
I used the same test to validate it (and extended it to test the new capabilities).

[magiconair]

I'd prefer if you compile the glob matcher in the test since this keeps the changeset smaller, e.g.

for _, tt := range tests {
    t.Run(tt.uri, func(t *testing.T) {
        tt.route.Matcher = glob.MustCompile(tt.route.path)
        ...
    })
}

[magiconair]

I think Glob is a better name than Matcher.

[magiconair]

Please name this glob and also remove the github.com/ryanuber/go-glob library in a separate commit.

[magiconair]

What happens if this is an invalid pattern? Does it panic? You probably need to catch the error and return it.

[sharbov]

I'm not sure why you used the glob matcher here in the first place, can a host contain wildcards ?

[magiconair]

Good question. I'll check.

[magiconair]

Yes, you can have a route for *.example.com/foo

[magiconair]

I wrote a small benchmark to verify performance. gobwas is fast but only when the expression is pre-compiled. It is only 1.4 ms but this sits in the hot-path. However, there is no easy way to refactor this since Table is just a map[string]Routes. Might be a good time to finally change this to a struct. I'll have a look.

$ go test -bench .
goos: darwin
goarch: amd64
pkg: globbench
BenchmarkGlob/ryanuber-8         	20000000	        91.4 ns/op
BenchmarkGlob/gobwas-8           	 1000000	      1385 ns/op
BenchmarkGlob/gobwas-precompile-8         	200000000	         7.29 ns/op
PASS
ok  	globbench	5.537s

package main

import "testing"
import ryanuber "github.com/ryanuber/go-glob"
import gobwas "github.com/gobwas/glob"

var n int

func BenchmarkGlob(b *testing.B) {
	b.Run("ryanuber", func(b *testing.B) {
		for i := 0; i < b.N; i++ {
			if ryanuber.Glob("*.example.com", "foo.example.com") {
				n++
			}
		}
	})
	b.Run("gobwas", func(b *testing.B) {
		for i := 0; i < b.N; i++ {
			m := gobwas.MustCompile("*.example.com")
			if m.Match("foo.example.com") {
				n++
			}
		}
	})
	b.Run("gobwas-precompile", func(b *testing.B) {
		m := gobwas.MustCompile("*.example.com")
		for i := 0; i < b.N; i++ {
			if m.Match("foo.example.com") {
				n++
			}
		}
	})
	b.Log(n)
}