35 lines
717 B
Go
35 lines
717 B
Go
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package main
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import (
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"context"
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"fmt"
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"net/http"
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)
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func main() {
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helloWorldHandler := http.HandlerFunc(handle)
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http.Handle("/welcome", injectTraceID(helloWorldHandler))
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_ = http.ListenAndServe(":8080", nil)
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}
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func handle(_ http.ResponseWriter, r *http.Request) {
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value, ok := r.Context().Value("trace_id").(string)
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if ok {
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fmt.Println(value)
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}
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makeRequest(r.Context())
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}
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func makeRequest(_ context.Context) {
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// requesting to database with context
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}
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func injectTraceID(next http.Handler) http.Handler {
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return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
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ctx := context.WithValue(r.Context(), "trace_id", "12-21-33")
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req := r.WithContext(ctx)
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next.ServeHTTP(w, req)
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})
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}
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