graceful

This is a fork of Stretchr, Inc.'s graceful, a Go 1.3+ package enabling graceful shutdown of http.Handler servers. This fork allows more fine-grained control over when the server is shutdown.

Usage

Usage of Graceful is simple. Create your http.Handler and pass it to the Run function:

import (
	"fmt"
	"net/http"

	"github.com/andrew-d/graceful"
)

func main() {
	mux := http.NewServeMux()
	mux.HandleFunc("/", func(w http.ResponseWriter, req *http.Request) {
		fmt.Fprintf(w, "Welcome to the home page!")
	})

	// This will return when the server has shut down.
	graceful.Run(":3001", mux)
}

Or, create an instance of graceful.GracefulServer, configure the timeout, and have more control over when your server shuts down:

import (
	"fmt"
	"net/http"
	"time"

	"github.com/andrew-d/graceful"
)

func main() {
	mux := http.NewServeMux()
	mux.HandleFunc("/", func(w http.ResponseWriter, req *http.Request) {
		fmt.Fprintf(w, "Welcome to the home page!")
	})

	srv := graceful.NewServer()
	srv.Timeout = 60 * time.Second

	go func() {
		// ... catch signals, or otherwise wait to signal shutdown
		srv.Shutdown <- struct{}{}
	}()

	// This will return when the server has shut down.
	srv.Run(":3001", mux)
}

In addition to Run there are the http.Server counterparts ListenAndServe, ListenAndServeTLS and Serve, which allow additional configuration. See the examples for some fully-working demonstrations, or the documentation for the full API.

How It Works

When Graceful is asked to shutdown, it:

1. Disables Keep-Alive connections.
2. Closes the listening socket, allowing another process to listen on that port immediately.
3. Starts a timer of timeout duration to give active requests a chance to finish.
4. If the timeout expires, forcefully closes all active connections.
5. Returns from the function, allowing the server to terminate.

Notes

• If the timeout value is 0, the server never times out, allowing all active requests to complete.
• Sending to the 'Shutdown' channel a second time will forcefully close all open connections.