package main import ( "fmt" "math/rand" "time" "github.com/micro/go-micro/client" "github.com/micro/go-micro/cmd" example "github.com/micro/go-micro/examples/server/proto/example" "github.com/micro/go-micro/registry" "github.com/micro/go-micro/selector" "golang.org/x/net/context" ) func init() { rand.Seed(time.Now().Unix()) } // Built in random hashed node selector type firstNodeSelector struct { opts selector.Options } func (n *firstNodeSelector) Select(service string, opts ...selector.SelectOption) (selector.Next, error) { services, err := n.opts.Registry.GetService(service) if err != nil { return nil, err } if len(services) == 0 { return nil, selector.ErrNotFound } var sopts selector.SelectOptions for _, opt := range opts { opt(&sopts) } for _, filter := range sopts.Filters { services = filter(services) } if len(services) == 0 { return nil, selector.ErrNotFound } if len(services[0].Nodes) == 0 { return nil, selector.ErrNotFound } return func() (*registry.Node, error) { return services[0].Nodes[0], nil }, nil } func (n *firstNodeSelector) Mark(service string, node *registry.Node, err error) { return } func (n *firstNodeSelector) Reset(service string) { return } func (n *firstNodeSelector) Close() error { return nil } func (n *firstNodeSelector) String() string { return "first" } // Return a new first node selector func FirstNodeSelector(opts ...selector.Option) selector.Selector { var sopts selector.Options for _, opt := range opts { opt(&sopts) } if sopts.Registry == nil { sopts.Registry = registry.DefaultRegistry } return &firstNodeSelector{sopts} } func call(i int) { // Create new request to service go.micro.srv.example, method Example.Call req := client.NewRequest("go.micro.srv.example", "Example.Call", &example.Request{ Name: "John", }) rsp := &example.Response{} // Call service if err := client.Call(context.Background(), req, rsp); err != nil { fmt.Println("call err: ", err, rsp) return } fmt.Println("Call:", i, "rsp:", rsp.Msg) } func main() { cmd.Init() client.DefaultClient = client.NewClient( client.Selector(FirstNodeSelector()), ) fmt.Println("\n--- Call example ---\n") for i := 0; i < 10; i++ { call(i) } }