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server_routes.go
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/
server_routes.go
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package copper
import (
"fmt"
"reflect"
)
type serverRouteCase struct {
sub *serverSubscription
weight uint32
}
type serverRoute struct {
owner *server
name string
routes []Route
cases []serverRouteCase
subscriptions map[*serverSubscription]struct{}
}
var _ endpointReference = &serverRoute{}
func (r *serverRoute) getEndpointsRLocked() []Endpoint {
var result []Endpoint
for _, c := range r.cases {
if c.weight > 0 && c.sub.isActiveRLocked() {
result = append(result, c.sub.getEndpointsRLocked()...)
}
}
return result
}
func (r *serverRoute) handleRequestRLocked(callback handleRequestCallback, cancel <-chan struct{}) handleRequestStatus {
sum := int64(0)
for _, c := range r.cases {
if c.weight > 0 && c.sub.isActiveRLocked() {
sum += int64(c.weight)
}
}
if sum == 0 {
// There are no routes
return handleRequestStatusNoRoute
}
bin := globalRandom.Int63n(sum)
for _, c := range r.cases {
if c.weight > 0 && c.sub.isActiveRLocked() {
if bin < int64(c.weight) {
return c.sub.handleRequestRLocked(callback, cancel)
}
bin -= int64(c.weight)
}
}
// this should never happen!
panic(fmt.Errorf("random number %d didn't match the sum %d", bin, sum))
}
func (s *server) setRouteLocked(name string, routes []Route) error {
r := s.routeByName[name]
if r == nil {
if len(routes) == 0 {
// Don't do anything if this call is trying to drop the route
return nil
}
r = &serverRoute{
owner: s,
name: name,
routes: routes,
subscriptions: make(map[*serverSubscription]struct{}),
}
s.routeByName[name] = r
if subs := s.subsByName[name]; subs != nil {
for sub := range subs {
sub.addRouteLocked(r)
}
}
} else if len(routes) == 0 {
for sub := range r.subscriptions {
sub.removeRouteLocked(r)
}
r.subscriptions = nil
for _, c := range r.cases {
c.sub.unsubscribeLocked()
}
r.cases = nil
r.routes = nil
delete(s.routeByName, name)
if log := DebugLog(); log != nil {
log.Printf("Route %s: removed", name)
}
return nil
} else {
if reflect.DeepEqual(r.routes, routes) {
// Don't do anything if routes didn't actually change
return nil
}
for _, c := range r.cases {
c.sub.unsubscribeLocked()
}
r.cases = nil
r.routes = routes
}
// we need to build our cases
r.cases = make([]serverRouteCase, len(r.routes))
for index, route := range r.routes {
sub, err := s.subscribeLocked(SubscribeSettings{
Options: route.Options,
DisableRoutes: true,
})
if err != nil {
panic(fmt.Errorf("unexpected subscribe error: %s", err))
}
r.cases[index].sub = sub
r.cases[index].weight = route.Weight
}
if log := DebugLog(); log != nil {
log.Printf("Route %s: setting to %v", name, routes)
}
return nil
}