Wait for daemon to come up; exit daemon gracefully.

daemon/daemon.go

@@ -72,7 +72,7 @@ func (d *Daemon) Main(serve func(string, string)) int {
 			})
 	case 2:
 		serve(d.SockPath, d.DbPath)
-		panic("unreachable")
+		return 0
 	default:
 		return 2
 	}

daemon/service/service.go

@@ -39,13 +39,20 @@ func Serve(sockpath, dbpath string) {
 	signal.Notify(quitSignals, syscall.SIGTERM, syscall.SIGINT)
 	go func() {
 		sig := <-quitSignals
-		logger.Printf("received signal %s, shutting down", sig)
+		logger.Printf("received signal %s", sig)
 		err := os.Remove(sockpath)
 		if err != nil {
-			logger.Println("failed to remove socket %s: %v", sockpath, err)
+			logger.Printf("failed to remove socket %s: %v", sockpath, err)
 		}
-		logger.Println("exiting")
-		os.Exit(0)
+		err = st.Close()
+		if err != nil {
+			logger.Printf("failed to close storage: %v", err)
+		}
+		err = listener.Close()
+		if err != nil {
+			logger.Printf("failed to close listener: %v", err)
+		}
+		logger.Println("listener closed, waiting to exit")
 	}()
 
 	service := &Service{st}
@@ -53,7 +60,8 @@ func Serve(sockpath, dbpath string) {
 
 	logger.Println("starting to serve RPC calls")
 	rpc.Accept(listener)
-	os.Exit(0)
+
+	logger.Println("exiting")
 }
 
 // Service provides the daemon RPC service.

edit/history.go

@@ -43,6 +43,10 @@ func (h *hist) ModeLine() renderer {
 }
 
 func historyStart(ed *Editor) {
+	if ed.historyFuser == nil {
+		ed.Notify("history offline")
+		return
+	}
 	prefix := ed.line[:ed.dot]
 	walker := ed.historyFuser.Walker(prefix)
 	ed.hist = hist{walker}
@@ -85,7 +89,7 @@ func historyDefault(ed *Editor) {
 // Implementation.
 
 func (ed *Editor) appendHistory(line string) {
-	if ed.daemon != nil {
+	if ed.daemon != nil && ed.historyFuser != nil {
 		ed.historyMutex.Lock()
 		ed.daemon.Waits().Add(1)
 		go func() {

main.go

@@ -16,6 +16,7 @@ import (
 	"runtime/pprof"
 	"strconv"
 	"syscall"
+	"time"
 
 	"github.com/elves/elvish/daemon"
 	"github.com/elves/elvish/daemon/api"
@@ -143,6 +144,12 @@ func main() {
 	}
 }
 
+const (
+	daemonWaitOneLoop = 10 * time.Millisecond
+	daemonWaitLoops   = 100
+	daemonWaitTotal   = daemonWaitOneLoop * daemonWaitLoops
+)
+
 func initRuntime() (*eval.Evaler, *api.Client) {
 	var dataDir string
 	var err error
@@ -199,7 +206,7 @@ func initRuntime() (*eval.Evaler, *api.Client) {
 					fmt.Fprintln(os.Stderr, "warning: failed to kill outdated daemon process:", err)
 					goto spawnDaemonEnd
 				}
-				fmt.Fprintln(os.Stderr, "killed outdated daemon")
+				logger.Println("killed outdated daemon")
 				killed = true
 			}
 		}
@@ -209,7 +216,19 @@ func initRuntime() (*eval.Evaler, *api.Client) {
 			if err != nil {
 				fmt.Fprintln(os.Stderr, "warning: cannot start daemon:", err)
 			} else {
-				fmt.Fprintln(os.Stderr, "started daemon")
+				logger.Println("started daemon")
+			}
+			for i := 0; i < daemonWaitLoops; i++ {
+				_, err := cl.Version()
+				if err == nil {
+					logger.Println("daemon online")
+					goto spawnDaemonEnd
+				} else if i == daemonWaitLoops-1 {
+					fmt.Fprintf(os.Stderr, "cannot connect to daemon after %v: %v\n", daemonWaitTotal, err)
+					cl = nil
+					goto spawnDaemonEnd
+				}
+				time.Sleep(daemonWaitOneLoop)
 			}
 		}
 	}