snapshot of https://github.com/go-chi/chi.git (master, 2026-09-15; blobs > 131072B omitted)

_examples/limits/main.go

@@ -0,0 +1,92 @@
+// This example demonstrates the use of Timeout, and Throttle middlewares.
+//
+// Timeout: cancel a request if processing takes longer than 2.5 seconds,
+// server will respond with a http.StatusGatewayTimeout.
+//
+// Throttle: limit the number of in-flight requests along a particular
+// routing path and backlog the others.
+package main
+
+import (
+	"context"
+	"fmt"
+	"math/rand"
+	"net/http"
+	"time"
+
+	"github.com/go-chi/chi/v5"
+	"github.com/go-chi/chi/v5/middleware"
+)
+
+func main() {
+	r := chi.NewRouter()
+
+	r.Use(middleware.RequestID)
+	r.Use(middleware.Logger)
+	r.Use(middleware.Recoverer)
+
+	r.Get("/", func(w http.ResponseWriter, r *http.Request) {
+		w.Write([]byte("root."))
+	})
+
+	r.Get("/ping", func(w http.ResponseWriter, r *http.Request) {
+		w.Write([]byte("pong"))
+	})
+
+	r.Get("/panic", func(w http.ResponseWriter, r *http.Request) {
+		panic("test")
+	})
+
+	// Slow handlers/operations.
+	r.Group(func(r chi.Router) {
+		// Stop processing after 2.5 seconds.
+		r.Use(middleware.Timeout(2500 * time.Millisecond))
+
+		r.Get("/slow", func(w http.ResponseWriter, r *http.Request) {
+			rand.Seed(time.Now().Unix())
+
+			// Processing will take 1-5 seconds.
+			processTime := time.Duration(rand.Intn(4)+1) * time.Second
+
+			select {
+			case <-r.Context().Done():
+				return
+
+			case <-time.After(processTime):
+				// The above channel simulates some hard work.
+			}
+
+			w.Write([]byte(fmt.Sprintf("Processed in %v seconds\n", processTime)))
+		})
+	})
+
+	// Throttle very expensive handlers/operations.
+	r.Group(func(r chi.Router) {
+		// Stop processing after 30 seconds.
+		r.Use(middleware.Timeout(30 * time.Second))
+
+		// Only one request will be processed at a time.
+		r.Use(middleware.Throttle(1))
+
+		r.Get("/throttled", func(w http.ResponseWriter, r *http.Request) {
+			select {
+			case <-r.Context().Done():
+				switch r.Context().Err() {
+				case context.DeadlineExceeded:
+					w.WriteHeader(504)
+					w.Write([]byte("Processing too slow\n"))
+				default:
+					w.Write([]byte("Canceled\n"))
+				}
+				return
+
+			case <-time.After(5 * time.Second):
+				// The above channel simulates some hard work.
+			}
+
+			w.Write([]byte("Processed\n"))
+		})
+	})
+
+	http.ListenAndServe(":3333", r)
+}