88 lines
2.0 KiB
Go
88 lines
2.0 KiB
Go
/*
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An example of how to use client.Wrapper as middleware
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*/
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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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c "github.com/micro/go-micro/context"
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example "github.com/micro/go-micro/examples/server/proto/example"
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"golang.org/x/net/context"
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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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func (l *logWrapper) Call(ctx context.Context, req client.Request, rsp interface{}) error {
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md, _ := c.GetMetadata(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{}) error {
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ctx = c.WithMetadata(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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// Calls the example service
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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 := c.WithMetadata(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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}
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func main() {
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cmd.Init()
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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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// 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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