From 066c169845d48194761e8db9f3884d367eb64f15 Mon Sep 17 00:00:00 2001
From: Asim <asim@chuhnk.me>
Date: Wed, 9 Dec 2015 15:06:31 +0000
Subject: [PATCH] Add example dc filter
---
examples/client/dc_filter/dc_filter.go | 84 ++++++++++++++++++++++++++
examples/server/main.go | 4 ++
2 files changed, 88 insertions(+)
create mode 100644 examples/client/dc_filter/dc_filter.go
diff --git a/examples/client/dc_filter/dc_filter.go b/examples/client/dc_filter/dc_filter.go
new file mode 100644
index 00000000..1795edc5
--- /dev/null
+++ b/examples/client/dc_filter/dc_filter.go
@@ -0,0 +1,84 @@
+package main
+
+import (
+ "fmt"
+ "math/rand"
+ "time"
+
+ "github.com/micro/go-micro/client"
+ "github.com/micro/go-micro/cmd"
+ c "github.com/micro/go-micro/context"
+ example "github.com/micro/go-micro/examples/server/proto/example"
+ "github.com/micro/go-micro/registry"
+ "golang.org/x/net/context"
+)
+
+func init() {
+ rand.Seed(time.Now().Unix())
+}
+
+// A Wrapper that creates a Datacenter Selector Option
+type dcWrapper struct {
+ client.Client
+}
+
+func (dc *dcWrapper) Call(ctx context.Context, req client.Request, rsp interface{}, opts ...client.CallOption) error {
+ md, _ := c.GetMetadata(ctx)
+
+ filter := func(services []*registry.Service) []*registry.Service {
+ for _, service := range services {
+ var nodes []*registry.Node
+ for _, node := range service.Nodes {
+ if node.Metadata["datacenter"] == md["datacenter"] {
+ nodes = append(nodes, node)
+ }
+ }
+ service.Nodes = nodes
+ }
+ return services
+ }
+
+ callOptions := append(opts, client.WithSelectOption(registry.SelectFilter(filter)))
+
+ fmt.Printf("[DC Wrapper] filtering for datacenter %s\n", md["datacenter"])
+ return dc.Client.Call(ctx, req, rsp, callOptions...)
+}
+
+func NewDCWrapper(c client.Client) client.Client {
+ return &dcWrapper{c}
+}
+
+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",
+ })
+
+ // create context with metadata
+ ctx := c.WithMetadata(context.Background(), map[string]string{
+ "datacenter": "local",
+ })
+
+ rsp := &example.Response{}
+
+ // Call service
+ if err := client.Call(ctx, 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.Wrap(NewDCWrapper),
+ )
+
+ fmt.Println("\n--- Call example ---\n")
+ for i := 0; i < 10; i++ {
+ call(i)
+ }
+}
diff --git a/examples/server/main.go b/examples/server/main.go
index 0f5e8329..193fd499 100644
--- a/examples/server/main.go
+++ b/examples/server/main.go
@@ -31,9 +31,13 @@ func main() {
// optionally setup command line usage
cmd.Init()
+ md := server.Config().Metadata()
+ md["datacenter"] = "local"
+
server.DefaultServer = server.NewServer(
server.WrapHandler(logWrapper),
server.WrapSubscriber(logSubWrapper),
+ server.Metadata(md),
)
// Initialise Server