Polish the routing source code

[mathetake]

I added the very naive implementation in #50

ai-gateway/internal/extproc/router/router.go

Lines 30 to 69 in a77bfc2

	// Calculate implements [Router.Calculate].
	func (r *router) Calculate(headers map[string]string) (backendName string, outputSchema extprocconfig.VersionedAPISchema, err error) {
	var rule *extprocconfig.RouteRule
	for i := range r.rules {
	_rule := &r.rules[i]
	for _, hdr := range _rule.Headers {
	v, ok := headers[string(hdr.Name)]
	// Currently, we only do the exact matching.
	if ok && v == hdr.Value {
	rule = _rule
	break
	}
	}
	}
	if rule == nil {
	return "", extprocconfig.VersionedAPISchema{}, errors.New("no matching rule found")
	}
	backendName, outputSchema = r.selectBackendFromRule(rule)
	return
	}
	func (r *router) selectBackendFromRule(rule *extprocconfig.RouteRule) (backendName string, outputSchema extprocconfig.VersionedAPISchema) {
	// Each backend has a weight, so we randomly select depending on the weight.
	// This is a pretty naive implementation and can be buggy, so fix it later.
	totalWeight := 0
	for _, b := range rule.Backends {
	totalWeight += b.Weight
	}
	if totalWeight == 0 {
	return rule.Backends[0].Name, rule.Backends[0].OutputSchema
	}
	selected := r.rng.Intn(totalWeight)
	for _, b := range rule.Backends {
	if selected < b.Weight {
	return b.Name, b.OutputSchema
	}
	selected -= b.Weight
	}
	return rule.Backends[0].Name, rule.Backends[0].OutputSchema
	}

which I think we should refactor before v0.1.0

[theBeginner86]

Hi @mathetake,
May I help in improving this?

[mathetake]

nah i am sorry but i would rather one of maintainers to take care of this, but thanks for the offer anyways

[liangyuanpeng]

I'm click into here because the help wanted label.

but i would rather one of maintainers to take care of this

And seems like this probably not need to add the help wanted label (:

[mathetake]

fair enough - removed the label

[wengyao04]

@mathetake does any maintainer takes care of this issue ? If not, I can help on it

[mathetake]

Yeah go for it

[mathetake]

ping @wengyao04 any updates?

[wengyao04]

ping @wengyao04 any updates?

I am testing out the ai-gateway within BB for all the integration, since there are lots of change after we switch to open source version, we have to fix our components to fit this change. Sorry I don't have time this week, and pick it up next week.