92 lines
		
	
	
		
			2.1 KiB
		
	
	
	
		
			Go
		
	
	
	
	
	
			
		
		
	
	
			92 lines
		
	
	
		
			2.1 KiB
		
	
	
	
		
			Go
		
	
	
	
	
	
| package main
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| 
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| import (
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| 	"fmt"
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| 	"time"
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| 
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| 	"github.com/micro/go-micro/client"
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| 	"github.com/micro/go-micro/cmd"
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| 	example "github.com/micro/go-micro/examples/server/proto/example"
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| 	"github.com/micro/go-micro/metadata"
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| 	"golang.org/x/net/context"
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| )
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| 
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| // wrapper example code
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| 
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| // log wrapper logs every time a request is made
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| type logWrapper struct {
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| 	client.Client
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| }
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| 
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| func (l *logWrapper) Call(ctx context.Context, req client.Request, rsp interface{}, opts ...client.CallOption) error {
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| 	md, _ := metadata.FromContext(ctx)
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| 	fmt.Printf("[Log Wrapper] ctx: %v service: %s method: %s\n", md, req.Service(), req.Method())
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| 	return l.Client.Call(ctx, req, rsp)
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| }
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| 
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| // trace wrapper attaches a unique trace ID - timestamp
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| type traceWrapper struct {
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| 	client.Client
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| }
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| 
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| func (t *traceWrapper) Call(ctx context.Context, req client.Request, rsp interface{}, opts ...client.CallOption) error {
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| 	ctx = metadata.NewContext(ctx, map[string]string{
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| 		"X-Trace-Id": fmt.Sprintf("%d", time.Now().Unix()),
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| 	})
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| 	return t.Client.Call(ctx, req, rsp)
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| }
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| 
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| // Implements client.Wrapper as logWrapper
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| func logWrap(c client.Client) client.Client {
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| 	return &logWrapper{c}
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| }
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| 
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| // Implements client.Wrapper as traceWrapper
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| func traceWrap(c client.Client) client.Client {
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| 	return &traceWrapper{c}
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| }
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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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| 
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| 	// create context with metadata
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| 	ctx := metadata.NewContext(context.Background(), map[string]string{
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| 		"X-User-Id": "john",
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| 		"X-From-Id": "script",
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| 	})
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| 
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| 	rsp := &example.Response{}
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| 
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| 	// Call service
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| 	if err := client.Call(ctx, 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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| 
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| 	fmt.Println("Call:", i, "rsp:", rsp.Msg)
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| }
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| 
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| func main() {
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| 	cmd.Init()
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| 
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| 	fmt.Println("\n--- Log Wrapper example ---\n")
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| 
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| 	// Wrap the default client
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| 	client.DefaultClient = logWrap(client.DefaultClient)
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| 
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| 	call(0)
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| 
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| 	fmt.Println("\n--- Log+Trace Wrapper example ---\n")
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| 
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| 	// Wrap using client.Wrap option
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| 	client.DefaultClient = client.NewClient(
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| 		client.Wrap(traceWrap),
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| 		client.Wrap(logWrap),
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| 	)
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| 
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| 	call(1)
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| }
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