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74 lines
2.0 KiB
74 lines
2.0 KiB
package main
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import (
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"os"
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"os/signal"
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"syscall"
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"time"
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"github.com/Scalingo/go-graceful-restart-example/logger"
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"github.com/Scalingo/go-graceful-restart-example/server"
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)
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func main() {
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log := logger.New("Server")
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var s *server.Server
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var err error
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if os.Getenv("_GRACEFUL_RESTART") == "true" {
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s, err = server.NewFromFD(log, 4)
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} else {
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s, err = server.New(log, 12345)
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}
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if err != nil {
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log.Fatalln("fail to init server:", err)
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}
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log.Println("Listen on", s.Addr())
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go s.StartAcceptLoop()
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signals := make(chan os.Signal)
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signal.Notify(signals, syscall.SIGHUP, syscall.SIGTERM)
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for sig := range signals {
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if sig == syscall.SIGTERM {
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// Stop accepting new connections
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s.Stop()
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// Wait a maximum of 10 seconds for existing connections to finish
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err := s.WaitWithTimeout(10 * time.Second)
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if err == server.WaitTimeoutError {
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log.Printf("Timeout when stopping server, %d active connections will be cut.\n", s.ConnectionsCounter())
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os.Exit(-127)
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}
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// Then the program exists
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log.Println("Server shutdown successful")
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os.Exit(0)
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} else if sig == syscall.SIGHUP {
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// Stop accepting requests
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s.Stop()
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// Get socket file descriptor to pass it to fork
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listenerFD, err := s.ListenerFD()
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if err != nil {
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log.Fatalln("Fail to get socket file descriptor:", err)
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}
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// Set a flag for the new process start process
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os.Setenv("_GRACEFUL_RESTART", "true")
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execSpec := &syscall.ProcAttr{
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Env: os.Environ(),
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Files: []uintptr{os.Stdin.Fd(), os.Stdout.Fd(), os.Stderr.Fd(), listenerFD},
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}
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// Fork exec the new version of your server
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fork, err := syscall.ForkExec(os.Args[0], os.Args, execSpec)
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if err != nil {
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log.Fatalln("Fail to fork1", err)
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}
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log.Println("SIGHUP received: fork-exec to", fork)
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// Wait for all conections to be finished
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s.Wait()
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log.Println(os.Getpid(), "Server gracefully shutdown")
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// Stop the old server, all the connections have been closed and the new one is running
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os.Exit(0)
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}
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}
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}
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