func (r *Label) Search(ctx context.Context, req *proto.SearchRequest, rsp *proto.SearchResponse) error {
if req.Limit <= 0 {
req.Limit = 10
}
if req.Offset <= 0 {
req.Offset = 0
}
labels, err := label.Search(req.Service, req.Key, req.Limit, req.Offset)
if err != nil {
return errors.InternalServerError("go.micro.srv.router.Label.Search", err.Error())
}
rsp.Labels = labels
return nil
}
func (r *router) Select(service string) ([]*proto.Service, error) {
if len(service) == 0 {
return nil, errors.New("invalid service")
}
// TODO: cache records or watch for updates
services, err := r.r.GetService(service)
if err != nil {
return nil, err
}
srvLen := len(services)
if srvLen == 0 {
return nil, selector.ErrNotFound
}
// grab dynamic runtime labels
// argh all the labels
// bad bad bad, don't use 1000
// TODO: fix. also cache
labels, err := label.Search(service, "", 1000, 0)
if err != nil {
return nil, err
}
// grab manually defined rules
// these are overrides to load balancing
// TODO: cache. also fix
rules, err := rule.Search(service, "", 1000, 0)
if err != nil {
return nil, err
}
// TODO: use stats to assign weights to nodes
// rather than just arbitrary pointer selection
// get the pointer and increment it
r.mtx.Lock()
pointer := r.pointers[service]
pointer++
r.pointers[service] = pointer
r.mtx.Unlock()
servs := make([]*proto.Service, srvLen)
// create starting point based on pointer and length of services
i := pointer % srvLen
// iterate through the length of the services
for j := 0; j < srvLen; j++ {
// if the pointer has dropped past length rotate back through
if i >= srvLen {
i = 0
}
// apply the label
label.Apply(labels, services[i])
// save the service, pass pointer toProto so it can rotate too
servs[j] = toProto(services[i], pointer)
i++
}
// we've load balanced the nodes
// now lets strip based on manual overrides
// TODO: accept label overrides
// Rules:
// service A version latest weight 0 priority 0
// service A version latest weight 100 priority 0 key=foo value=bar
// if a Select provides the label foo=bar then we'll return it
// even where previously the weight was set to 0
var final []*proto.Service
// TODO: should be provided as params to this method
userSelectLabels := map[string]string{}
for _, service := range servs {
if s := rule.Apply(rules, service, userSelectLabels); s != nil {
final = append(final, s)
}
}
return final, nil
}