92 lines
		
	
	
		
			2.1 KiB
		
	
	
	
		
			Go
		
	
	
	
	
	
			
		
		
	
	
			92 lines
		
	
	
		
			2.1 KiB
		
	
	
	
		
			Go
		
	
	
	
	
	
package main
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import (
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	"fmt"
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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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	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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// wrapper example code
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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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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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// 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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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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// 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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// 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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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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	// 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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	rsp := &example.Response{}
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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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	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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	fmt.Println("\n--- Log Wrapper example ---\n")
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	// Wrap the default client
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	client.DefaultClient = logWrap(client.DefaultClient)
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	call(0)
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	fmt.Println("\n--- Log+Trace Wrapper example ---\n")
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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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	call(1)
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}
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