⚡ Implement force caching of instances by the daemon

README.md

@@ -86,6 +86,14 @@ Here's annotation for every paramater of the default config:
 # You can use modifier keys `shift` and `control`.
 # To identify some complex keybind use `xbindkeys` tool.
 keybind: mod4-q
+# How often should projektor daemon run an instance in the background with
+# '-dry' flag?
+# The dry instances are run to force the kernel to cache all the data needed
+# by projektor to run. By forcing the caching we can enable projektor instances
+# to startup faster.
+# The interval is specified in seconds. Set to 0 if you want to disable
+# the force caching completely.
+forcecacheinterval: 60
 # Searching categories, enabled for use.
 # Disable a category by settings its flag to `false` and projektor will no longer
 # offer you entries of that category.

config.go

@@ -1,15 +1,17 @@
 package main
 
 import (
-	"gopkg.in/yaml.v2"
 	"io/ioutil"
 	"os"
 	"path"
+
+	"gopkg.in/yaml.v2"
 )
 
 type ProjektorConfig struct {
-	KeyBind           string
-	EnabledCategories struct {
+	KeyBind            string
+	ForceCacheInterval int64
+	EnabledCategories  struct {
 		Calc      bool
 		History   bool
 		Apps      bool
@@ -39,6 +41,7 @@ func DefaultConfig() *ProjektorConfig {
 	c := &ProjektorConfig{}
 
 	c.KeyBind = "mod4-q"
+	c.ForceCacheInterval = 60
 
 	c.EnabledCategories.Calc = true
 	c.EnabledCategories.History = true

kill_running.go

@@ -21,6 +21,10 @@ func KillIfOtherInstance(p ps.Process) bool {
 		return false
 	}
 
+	if strings.Contains(p.Cmdline(), "-dry") {
+		return false
+	}
+
 	osproc, err := os.FindProcess(p.Pid())
 	if err != nil {
 		return false

main.go

@@ -9,6 +9,7 @@ import (
 	"os"
 	"os/exec"
 	"runtime/pprof"
+	"time"
 
 	"github.com/BurntSushi/xgbutil"
 	"github.com/BurntSushi/xgbutil/keybind"
@@ -51,6 +52,22 @@ func RunInstance(dry bool) {
 func RunDaemon() {
 	logf("Running key binding daemon of projektor\n")
 
+	fci := Config.ForceCacheInterval
+	if fci > 0 {
+		go func() {
+			for {
+				logf("Running dry instance...\n")
+				cmd := exec.Command(os.Args[0], "-"+SIFlag, "-dry")
+				err := cmd.Start()
+				if err != nil {
+					errduring("dry instance creation", err, "")
+				}
+				go cmd.Wait()
+				time.Sleep(time.Duration(fci) * time.Second)
+			}
+		}()
+	}
+
 	xu, err := xgbutil.NewConn()
 	if err != nil {
 		log.Fatal(err)