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