add support for overriding service templates at runtime

service.go

@@ -81,6 +81,11 @@ const (
 	optionRunWait      = "RunWait"
 	optionReloadSignal = "ReloadSignal"
 	optionPIDFile      = "PIDFile"
+
+	optionSystemdScript = "SystemdScript"
+	optionSysvScript    = "SysvScript"
+	optionUpstartScript = "UpstartScript"
+	optionLaunchdConfig = "LaunchdConfig"
 )
 
 // Config provides the setup for a Service. The Name field is required.
@@ -105,15 +110,19 @@ type Config struct {
 
 	// System specific options.
 	//  * OS X
-	//    - KeepAlive     bool (true)
-	//    - RunAtLoad     bool (false)
-	//    - UserService   bool (false) - Install as a current user service.
-	//    - SessionCreate bool (false) - Create a full user session.
+	//    - LaunchdConfig string ()      - Use custom launchd config
+	//    - KeepAlive     bool   (true)
+	//    - RunAtLoad     bool   (false)
+	//    - UserService   bool   (false) - Install as a current user service.
+	//    - SessionCreate bool   (false) - Create a full user session.
 	//  * POSIX
-	//    - RunWait       func() (wait for SIGNAL) - Do not install signal but wait for this function to return.
-	//    - ReloadSignal  string () [USR1, ...] - Signal to send on reaload.
+	//    - SystemdScript string ()                 - Use custom systemd script
+	//    - UpstartScript string ()                 - Use custom upstart script
+	//    - SysvScript    string ()                 - Use custom sysv script
+	//    - RunWait       func() (wait for SIGNAL)  - Do not install signal but wait for this function to return.
+	//    - ReloadSignal  string () [USR1, ...]     - Signal to send on reaload.
 	//    - PIDFile       string () [/run/prog.pid] - Location of the PID file.
-	//    - LogOutput     bool   (false) - Redirect StdErr & StdOut to files.
+	//    - LogOutput     bool   (false)            - Redirect StdErr & StdOut to files.
 	Option KeyValue
 }
 

service_darwin.go

@@ -100,6 +100,25 @@ func (s *darwinLaunchdService) getServiceFilePath() (string, error) {
 	return "/Library/LaunchDaemons/" + s.Name + ".plist", nil
 }
 
+func (s *darwinLaunchdService) template() *template.Template {
+	functions := template.FuncMap{
+		"bool": func(v bool) string {
+			if v {
+				return "true"
+			}
+			return "false"
+		},
+	}
+
+	customConfig := s.Option.string(optionLaunchdConfig, "")
+
+	if customConfig != "" {
+		return template.Must(template.New("").Funcs(functions).Parse(customConfig))
+	} else {
+		return template.Must(template.New("").Funcs(functions).Parse(launchdConfig))
+	}
+}
+
 func (s *darwinLaunchdService) Install() error {
 	confPath, err := s.getServiceFilePath()
 	if err != nil {
@@ -143,16 +162,7 @@ func (s *darwinLaunchdService) Install() error {
 		SessionCreate: s.Option.bool(optionSessionCreate, optionSessionCreateDefault),
 	}
 
-	functions := template.FuncMap{
-		"bool": func(v bool) string {
-			if v {
-				return "true"
-			}
-			return "false"
-		},
-	}
-	t := template.Must(template.New("launchdConfig").Funcs(functions).Parse(launchdConfig))
-	return t.Execute(f, to)
+	return s.template().Execute(f, to)
 }
 
 func (s *darwinLaunchdService) Uninstall() error {

service_systemd_linux.go

@@ -52,8 +52,15 @@ func (s *systemd) configPath() (cp string, err error) {
 	cp = "/etc/systemd/system/" + s.Config.Name + ".service"
 	return
 }
+
 func (s *systemd) template() *template.Template {
-	return template.Must(template.New("").Funcs(tf).Parse(systemdScript))
+	customScript := s.Option.string(optionSystemdScript, "")
+
+	if customScript != "" {
+		return template.Must(template.New("").Funcs(tf).Parse(customScript))
+	} else {
+		return template.Must(template.New("").Funcs(tf).Parse(systemdScript))
+	}
 }
 
 func (s *systemd) Install() error {

service_sysv_linux.go

@@ -45,8 +45,15 @@ func (s *sysv) configPath() (cp string, err error) {
 	cp = "/etc/init.d/" + s.Config.Name
 	return
 }
+
 func (s *sysv) template() *template.Template {
-	return template.Must(template.New("").Funcs(tf).Parse(sysvScript))
+	customScript := s.Option.string(optionSysvScript, "")
+
+	if customScript != "" {
+		return template.Must(template.New("").Funcs(tf).Parse(customScript))
+	} else {
+		return template.Must(template.New("").Funcs(tf).Parse(sysvScript))
+	}
 }
 
 func (s *sysv) Install() error {

service_upstart_linux.go

@@ -111,7 +111,13 @@ func (s *upstart) getUpstartVersion() []int {
 }
 
 func (s *upstart) template() *template.Template {
-	return template.Must(template.New("").Funcs(tf).Parse(upstartScript))
+	customScript := s.Option.string(optionUpstartScript, "")
+
+	if customScript != "" {
+		return template.Must(template.New("").Funcs(tf).Parse(customScript))
+	} else {
+		return template.Must(template.New("").Funcs(tf).Parse(upstartScript))
+	}
 }
 
 func (s *upstart) Install() error {