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package testing_test
import (
"context"
"errors"
"flag"
"fmt"
"log"
"net"
"net/http"
"os"
"os/signal"
"syscall"
"time"
"github.com/cloudflare/tableflip"
"github.com/cloudflare/tableflip/testing"
)
type upgrader interface {
Listen(network, addr string) (net.Listener, error)
Stop()
Upgrade() error
Ready() error
Exit() <-chan struct{}
}
// This shows how to use the upgrader
// with the graceful shutdown facilities of net/http
// and using the stub implementation if on an unsupported platform.
func Example_httpShutdown() {
var (
listenAddr = flag.String("listen", "localhost:8080", "`Address` to listen on")
pidFile = flag.String("pid-file", "", "`Path` to pid file")
)
flag.Parse()
log.SetPrefix(fmt.Sprintf("%d ", os.Getpid()))
var upg upgrader
upg, err := tableflip.New(tableflip.Options{
PIDFile: *pidFile,
})
if errors.Is(err, tableflip.ErrNotSupported) {
upg, _ = testing.New()
} else if err != nil {
panic(err)
}
defer upg.Stop()
// Do an upgrade on SIGHUP
// NOTE: With `testing.Upgrader` this goroutine is useless
// You may choose to enclose it inside an `if` statement block.
go func() {
sig := make(chan os.Signal, 1)
signal.Notify(sig, syscall.SIGHUP)
for range sig {
err := upg.Upgrade()
if err != nil {
log.Println("Upgrade failed:", err)
}
}
}()
// Listen must be called before Ready
ln, err := upg.Listen("tcp", *listenAddr)
if err != nil {
log.Fatalln("Can't listen:", err)
}
server := http.Server{
// Set timeouts, etc.
}
go func() {
err := server.Serve(ln)
if err != http.ErrServerClosed {
log.Println("HTTP server:", err)
}
}()
log.Printf("ready")
if err := upg.Ready(); err != nil {
panic(err)
}
<-upg.Exit()
// Make sure to set a deadline on exiting the process
// after upg.Exit() is closed. No new upgrades can be
// performed if the parent doesn't exit.
time.AfterFunc(30*time.Second, func() {
log.Println("Graceful shutdown timed out")
os.Exit(1)
})
// Wait for connections to drain.
server.Shutdown(context.Background())
}
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