106 lines
2.3 KiB
Go
106 lines
2.3 KiB
Go
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//
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// Limits
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// ======
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// This example demonstrates the use of Timeout, CloseNotify, and
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// Throttle middlewares.
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//
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// Timeout:
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// cancel a request if processing takes longer than 2.5 seconds,
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// server will respond with a http.StatusGatewayTimeout.
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//
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// CloseNotify:
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// cancel a request if the client disconnects.
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//
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// Throttle:
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// limit the number of in-flight requests along a particular
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// routing path and backlog the others.
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//
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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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"math/rand"
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"net/http"
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"time"
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"github.com/go-chi/chi"
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"github.com/go-chi/chi/middleware"
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)
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func main() {
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r := chi.NewRouter()
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r.Use(middleware.RequestID)
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r.Use(middleware.Logger)
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r.Use(middleware.Recoverer)
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r.Get("/", func(w http.ResponseWriter, r *http.Request) {
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w.Write([]byte("root."))
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})
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r.Get("/ping", func(w http.ResponseWriter, r *http.Request) {
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w.Write([]byte("pong"))
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})
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r.Get("/panic", func(w http.ResponseWriter, r *http.Request) {
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panic("test")
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})
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// Slow handlers/operations.
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r.Group(func(r chi.Router) {
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// Stop processing when client disconnects.
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r.Use(middleware.CloseNotify)
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// Stop processing after 2.5 seconds.
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r.Use(middleware.Timeout(2500 * time.Millisecond))
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r.Get("/slow", func(w http.ResponseWriter, r *http.Request) {
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rand.Seed(time.Now().Unix())
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// Processing will take 1-5 seconds.
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processTime := time.Duration(rand.Intn(4)+1) * time.Second
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select {
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case <-r.Context().Done():
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return
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case <-time.After(processTime):
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// The above channel simulates some hard work.
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}
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w.Write([]byte(fmt.Sprintf("Processed in %v seconds\n", processTime)))
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})
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})
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// Throttle very expensive handlers/operations.
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r.Group(func(r chi.Router) {
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// Stop processing after 30 seconds.
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r.Use(middleware.Timeout(30 * time.Second))
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// Only one request will be processed at a time.
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r.Use(middleware.Throttle(1))
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r.Get("/throttled", func(w http.ResponseWriter, r *http.Request) {
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select {
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case <-r.Context().Done():
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switch r.Context().Err() {
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case context.DeadlineExceeded:
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w.WriteHeader(504)
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w.Write([]byte("Processing too slow\n"))
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default:
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w.Write([]byte("Canceled\n"))
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}
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return
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case <-time.After(5 * time.Second):
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// The above channel simulates some hard work.
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}
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w.Write([]byte("Processed\n"))
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})
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})
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http.ListenAndServe(":3333", r)
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}
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