package roundrobin import ( "sync" "github.com/micro/go-micro/cmd" "github.com/micro/go-micro/registry" "github.com/micro/go-micro/selector" ) type roundRobinSelector struct { so selector.Options } func init() { cmd.DefaultSelectors["roundrobin"] = NewSelector } func (r *roundRobinSelector) Select(service string, opts ...selector.SelectOption) (selector.Next, error) { var sopts selector.SelectOptions for _, opt := range opts { opt(&sopts) } // get the service services, err := r.so.Registry.GetService(service) if err != nil { return nil, err } // apply the filters for _, filter := range sopts.Filters { services = filter(services) } // if there's nothing left, return if len(services) == 0 { return nil, selector.ErrNotFound } var nodes []*registry.Node for _, service := range services { for _, node := range service.Nodes { nodes = append(nodes, node) } } if len(nodes) == 0 { return nil, selector.ErrNotFound } var i int var mtx sync.Mutex return func() (*registry.Node, error) { mtx.Lock() defer mtx.Unlock() i++ return nodes[i%len(nodes)], nil }, nil } func (r *roundRobinSelector) Mark(service string, node *registry.Node, err error) { return } func (r *roundRobinSelector) Reset(service string) { return } func (r *roundRobinSelector) Close() error { return nil } func (r *roundRobinSelector) String() string { return "roundrobin" } func NewSelector(opts ...selector.Option) selector.Selector { var sopts selector.Options for _, opt := range opts { opt(&sopts) } if sopts.Registry == nil { sopts.Registry = registry.DefaultRegistry } return &roundRobinSelector{sopts} }