graceful

graceful

Graceful is a Go 1.3+ package enabling graceful shutdown of http.Handler servers.

Usage

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

import (
  "github.com/stretchr/graceful"
  "net/http"
  "fmt"
)

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

  graceful.Run(":3001",10*time.Second,mux)
}

Another example, using Negroni, functions in much the same manner:

package main

import (
  "github.com/codegangsta/negroni"
  "github.com/stretchr/graceful"
  "net/http"
  "fmt"
)

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

  n := negroni.Classic()
  n.UseHandler(mux)
  //n.Run(":3000")
  graceful.Run(":3001",10*time.Second,n)
}

In addition to Run there are the http.Server counterparts ListenAndServe, ListenAndServeTLS and Serve, these allow to configure https, custom timeouts and error handling.

When Graceful is sent a SIGINT (ctrl+c), it:

1. Disables keepalive 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. When timeout expires, closes all active connections.
5. Returns from the function, allowing the server to terminate.

Notes

If the timeout argument to Run is 0, the server never times out, allowing all active requests to complete.