installing service under systemd draft

.vscode/launch.json

@@ -7,7 +7,7 @@
             "type": "go",
             "request": "launch",
             "program": "main.go",
-            "args": ["info"]
+            "args": ["install"]
         }
     ]
 }

app/global.go

@@ -2,6 +2,7 @@
 package app
 
 import (
+	_ "embed"
 	"runtime"
 )
 
@@ -10,6 +11,9 @@ var BuildCommit = "DEV"
 
 const DefaultSettingsFilename = ".bot.yml"
 
+//go:embed mt-tgadmin.service.template
+var ServiceUnitFileTemplate string
+
 var Global struct {
 	AppName   string
 	Version   string
@@ -21,6 +25,8 @@ var Global struct {
 
 	BotInfo  string
 	ChatInfo string
+
+	ServiceAutostart bool
 }
 
 func init() {
@@ -36,6 +42,10 @@ func init() {
 	Global.Settings.GuiHostname = "localhost"
 	Global.Settings.GuiPort = 15080
 
+	Global.Settings.ServiceName = Global.AppName
+	Global.Settings.ServiceUser = "www-data"
+	Global.Settings.ServiceGroup = "www-data"
+
 	Global.BotInfo = "[undefined]"
 	Global.ChatInfo = "[undefined]"
 }

app/mt-tgadmin.service.template

@@ -0,0 +1,17 @@
+[Unit]
+Description={{ .Name }}
+After=network.target
+StartLimitIntervalSec=60
+StartLimitBurst=5
+
+[Service]
+RestartSec=2s
+Type=simple
+User={{ .User }}
+Group={{ .Group }}
+WorkingDirectory={{ .WorkingDir }}
+ExecStart={{ .Executable }} run
+Restart=always
+
+[Install]
+WantedBy=multi-user.target

app/settings.go

@@ -9,4 +9,8 @@ type Settings struct {
 	GuiPassword        string `yaml:"gui_password" yaml_comment:"GUI access password"`
 	GuiHostname        string `yaml:"gui_hostname" yaml_comment:"Web GUI hostname"`
 	GuiPort            uint16 `yaml:"gui_port" yaml_comment:"Web GUI port number"`
+
+	ServiceName  string `yaml:"service_name" yaml_comment:"Service name for 'install' command"`
+	ServiceUser  string `yaml:"service_user" yaml_comment:"User for 'install' command"`
+	ServiceGroup string `yaml:"service_group" yaml_comment:"Group for 'install' command"`
 }

cmd/install.go

@@ -0,0 +1,102 @@
+package cmd
+
+import (
+	"log"
+	"os"
+	"path"
+	"text/template"
+
+	"github.com/mitoteam/mt-tgadmin/app"
+	"github.com/mitoteam/mt-tgadmin/mttools"
+
+	"github.com/spf13/cobra"
+)
+
+const systemdServiceDirPath = "/usr/lib/systemd"
+
+func init() {
+	cmd := &cobra.Command{
+		Use:   "install",
+		Short: "Creates system service to run " + app.Global.AppName,
+
+		RunE: func(cmd *cobra.Command, args []string) error {
+			//log.Printf("Autostart %t\n", app.Global.ServiceAutostart)
+
+			if mttools.IsDirExists(systemdServiceDirPath) {
+				systemdServiceInstall()
+			} else {
+				log.Fatalf(
+					"Directory %s does not exists. Only systemd based services supported for now.\n",
+					systemdServiceDirPath,
+				)
+			}
+
+			return nil
+		},
+	}
+
+	cmd.PersistentFlags().BoolVar(
+		&app.Global.ServiceAutostart,
+		"autostart",
+		false,
+		"Set service to be auto started after boot. Please note this does not auto starts service after installation.",
+	)
+
+	rootCmd.AddCommand(cmd)
+}
+
+type serviceUnitData struct {
+	Name       string
+	User       string
+	Group      string
+	Executable string
+	WorkingDir string
+}
+
+func systemdServiceInstall() {
+	filename := path.Join(systemdServiceDirPath, app.Global.Settings.ServiceName+".service")
+
+	if mttools.IsFileExists(filename) {
+		log.Fatalf("File %s already exists. Use 'uninstall' command or remove file manually.\n", filename)
+	}
+
+	t := template.New("service")
+	if _, err := t.Parse(app.ServiceUnitFileTemplate); err != nil {
+		log.Fatalln(err)
+	}
+
+	executable, err := os.Executable()
+
+	if err != nil {
+		log.Fatalln(err)
+	}
+
+	workingDir, err := os.Getwd()
+
+	if err != nil {
+		log.Println(err)
+	}
+
+	data := &serviceUnitData{
+		Name:       app.Global.Settings.ServiceName,
+		User:       app.Global.Settings.ServiceUser,
+		Group:      app.Global.Settings.ServiceGroup,
+		Executable: executable,
+		WorkingDir: workingDir,
+	}
+
+	file, err := os.Create(filename)
+	if err != nil {
+		log.Fatalln(err)
+	}
+
+	if err := t.Execute(file, data); err != nil {
+		log.Fatalln(err)
+	}
+
+	file.Close()
+
+	if err := file.Chmod(0644); err != nil {
+		log.Fatal(err)
+	}
+}