func ContextInjector(componentName string, handler http.Handler) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
reqID := req.Header.Get("X-Request-ID")
if reqID == "" {
reqID = random.UUID()
}
ctx := ctxhelper.NewContextRequestID(context.Background(), reqID)
ctx = ctxhelper.NewContextComponentName(ctx, componentName)
rw := NewResponseWriter(w, ctx)
handler.ServeHTTP(rw, req)
})
}
func ExampleWithTimeout() {
// Pass a context with a timeout to tell a blocking function that it
// should abandon its work after the timeout elapses.
ctx, _ := context.WithTimeout(context.Background(), 100*time.Millisecond)
select {
case <-time.After(200 * time.Millisecond):
fmt.Println("overslept")
case <-ctx.Done():
fmt.Println(ctx.Err()) // prints "context deadline exceeded"
}
// Output:
// context deadline exceeded
}