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import "code.pfad.fr/risefront"
package risefront enables gracefully upgrading the server behing a tcp connection with zero-downtime (without disturbing running transfers or dropping incoming requests).
Code:
package main
import (
"context"
"errors"
"net"
"net/http"
"os"
"strconv"
"time"
"code.pfad.fr/risefront"
)
func newServer() *http.Server {
// This is an example server, which shows the PID of its process.
// Start processes in parallel to show the forwarding of the
// incoming connection to the latest process.
return &http.Server{
Handler: http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
w.Write([]byte("hello world " + strconv.Itoa(os.Getpid()) + "\n"))
if r.URL.Path == "/hang" {
time.Sleep(10 * time.Second)
}
w.Write([]byte("bye " + strconv.Itoa(os.Getpid())))
}),
}
}
func main() {
// In production, use signal.NotifyContext to interrupt on Ctrl+C:
// ctx, cancel := signal.NotifyContext(context.Background(), os.Interrupt)
ctx, cancel := context.WithTimeout(context.Background(), time.Second)
defer cancel()
err := risefront.New(ctx, risefront.Config{
Addresses: []string{":8080"},
Run: func(l []net.Listener) error {
// Example http.Server
s := newServer()
// defer Shutdown to wait for ongoing requests to be served before returning
defer s.Shutdown(context.Background())
return s.Serve(l[0]) // serve on the given listener
},
})
if !errors.Is(err, context.DeadlineExceeded) {
panic(err)
}
}
func New(ctx context.Context, cfg Config) error
New calls cfg.Run with opened listeners.
The parent will live as long as the context lives. The child will live as long as the parent is alive and no other child has been started.
type Config struct {
Addresses []string // Addresses to listen to.
Run func([]net.Listener) error // Handle the connections. All open connections should be properly closed before returning (srv.Shutdown for http.Server for instance).
Dialer Dialer // Dialer for child-parent communication. Let empty for default dialer (PrefixDialer{}).
Network string // "tcp" (default if empty), "tcp4", "tcp6", "unix" or "unixpacket"
ErrorHandler func(kind string, err error) // Where errors should be logged (print to stderr by default)
// contains filtered or unexported fields
}
type Dialer interface {
Listen(name string) (net.Listener, error)
Dial(name string) (net.Conn, error)
}
Dialer is used for the child-parent communication.
type PrefixDialer struct {
Prefix string
}
PrefixDialer uses github.com/Microsoft/go-winio.{DialPipe,ListenPipe} on windows and net.{Dial,Listen} on other platforms.
func (pd PrefixDialer) Dial(name string) (net.Conn, error)
func (pd PrefixDialer) Listen(name string) (net.Listener, error)