initial import

concurrency/graceful-shutdown/.vscode/settings.json

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+{
+    "go.formatTool": "goimports"
+}

concurrency/graceful-shutdown/go.mod

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+module graceful-shutdown
+
+go 1.12

concurrency/graceful-shutdown/main.go

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+package main
+
+import (
+	"context"
+	"fmt"
+	"log"
+	"net/http"
+	"os"
+	"os/signal"
+	"time"
+)
+
+func handle(w http.ResponseWriter, r *http.Request) {
+
+	select {
+	case <-time.After(60 * time.Second):
+		// If we receive a message after 2 seconds
+		// that means the request has been processed
+		// We then write this as the response
+		w.Write([]byte("request processed"))
+	case <-r.Context().Done():
+		// If the request gets cancelled, log it
+		// to STDERR
+		fmt.Fprint(os.Stderr, "request cancelled\n")
+	}
+
+}
+
+func main() {
+
+	srv := http.Server{Addr: ":8081"}
+
+	idleConnsClosed := make(chan struct{})
+
+	ctx, cancel := context.WithTimeout(context.Background(), 100*time.Second)
+	defer cancel()
+
+	go func() {
+		sigint := make(chan os.Signal, 1)
+		signal.Notify(sigint, os.Interrupt)
+		<-sigint
+		// We received an interrupt signal, shut down.
+		if err := srv.Shutdown(ctx); err != nil {
+			// Error from closing listeners, or context timeout:
+			log.Printf("HTTP server Shutdown: %v", err)
+		}
+		log.Print("HTTP server Shutdown successful")
+		close(idleConnsClosed)
+	}()
+
+	http.HandleFunc("/", handle)
+
+	if err := srv.ListenAndServe(); err != http.ErrServerClosed {
+		// Error starting or closing listener:
+		log.Printf("HTTP server ListenAndServe: %v", err)
+	}
+
+	<-idleConnsClosed
+
+}